text:
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Those with a knack for teaching can peruse online modules covering learning difficulties, educational outcomes and ethical considerations
Participants learn about personal training with course content covering topics such as anatomy, fitness goals and nutrition
Students can learn the ins and outs of web development, web design, or both courses over the course of online modules across devices
Customers can take a different approach to getting in shape with an up to five-year personal training membership
This course is designed to teach participants the essentials about creating, coding and publishing mobile applications
This CPD accredited course contains 90 modules that allows to get in shape fast, including what it takes to become a fitness instructor
Learn more about kids nutritional needs or the cycle of their development; those with a thirst for knowledge can opt for both courses
Learn how to create organisational structures, implement effective communication strategies and represent a brand during this online course
Featuring three interchangeable heads, this handheld massager helps to relax the muscles, relieve tension and soothe the nerves
Featuring a 500W motor and designed with travellers in mind this blender is available with two optional BPA-free bottles
Get the desired spray tan in the comfort of home with this convenient and easy-to-apply spray tan kit, ideal for beginners and professionals
AVG Internet Security protects personal devices against malware and ransomware, whilst Tuneup helps to optimise the performance of a PC
Ideal for small spaces or for table-top use, this heater features a 90° rotation function and 12-hour programmable timer
Perfect for coping with heat at home or in the office, this personal air cooler aims to cool, humidify and purify the air
This online course features over 30 modules designed to help budding fitness instructors and personal trainers up their game
This course is designed to develop skills in providing a dedicated one-to-one service for health and fitness clients
Students can learn about software development methodology with Agile Scrum or Agile Extreme Programming online course
Students of this bundle can gain skills in writing and editing HTML, CSS and JavaScript; includes three web-development online courses
Learn the process of mobile app creation, from beginning to end, during this online course including interactive webinars
Clients can work towards attaining their personal fitness goals during this online, tailor-made course
This course is designed to teach participants the essentials about personal beauty, including optimizing skincare for one's skin type
A written will ensures a fair distribution of assets gathered throughout a person's life, and constitutes the last personal statement
Those considering having a baby can get a number of tests including, anti-mullerian hormone, BMI, prolactin and follicel stimulating hormone
Beginner and intermediary players can polish their golf skills with the help of a trainer at a Toptracer driving range
Course is preparing to communicate with people who have disabling hearing loss in British Sign Language (BSL)
Participants can explore 12 online modules over the course of six months, and make use of tutor support and job placement assistance
Customers can learn about where their ancestors come from, both geographically and ethnically, all with just a swab sample of saliva
This course is sectioned into 21 modules to help learners obtain the attributes to become an efficient personal assistant and secretary
This online course allows the participant to learn about the aim of counselling, child psychology and development at their own pace
Customers can indulge in a pamper package lasting 60 minutes, with options such as facials and massages at this city centre salon
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text: You wouldn't head into the backcountry without one, so throw your Arva Guard V1 Shovel in your safety pouch and head out into the wilderness. Thanks to the lightweight aluminum construction, this shovel won't weigh you down while you're trying to crush big days in the backcountry, and the tough material is solid and durable. The handle gives you optimal leverage to dig quickly and efficiently, and the telescoping shaft snaps easily into place.

subset: commoncrawl


text:
Dion Wired has unveiled its first batch of Black Friday 2018 deals.
The retailer has published two catalogues with the first batch of deals, separated into "online" and "in-store" specials.
Dion Wired said its sale will run from 23-25 November for its in-store and online deals, and stores will open at midnight when the sale starts.
A selection of the first batch of Dion Wired Black Friday 2018 deals are shown below.
The company stated that more deals will be unveiled soon.
Online Deals
Fitbit Band – R1,999
Dell Laptop – R9,999
Canon Printer – R2,499
WD 4TB Hard Drive – R1,699
Logitech Speakers – R99
Console Games – From R399
iPhone SE – R3,799
Samsung Galaxy S9 – R11,999
In-Store Deals
iPad 6 – R4,499


text:
In this episode of the Innovation and the Digital Enterprise podcast, Randy Rivera stops by to chat with Pat & Shelli. Randy is a long time financial executive, entrepreneur and innovator in the emerging Fintech ecosystem. Randy gives his insights into the Chicago ecosystem, first as an executive then as an entrepreneur with quointec, the company he founded in 2018.
Show Notes
- [00:33] - Who is Randy Rivera?
- [06:50] - The Chicago business ecosystem
- [13:05] - What makes a founder?
- [17:52] - The first five
- [20:05] - Developing and growing a company
- [27:48] - The growing fintech space
- [33:41] - Today's Entrepreneurs
- [38:59] - What it takes to make it
- [43:43] - Tigers can't change their stripes
- [45:25] - Give and take people
- [50:43] - Failure and tools to succeed
What is Innovation and the Digital Enterprise?
The Innovation and the Digital Enterprise podcast is the ultimate resource for entrepreneurs and technology executives focused on influencing positive transformation that leads to organizational success. Join co-hosts DragonSpears' Patrick Emmons and Madison Industries' Shelli Nelson as they chat with guests from a variety of industries uncovering tips, tools, and insights gleaned from spearheading their own innovation initiatives.


text:
J. Cole's fourth album 4 Your Eyez Only drops Friday, December 9, exactly two years after his double platinum album 2014 Forest Hills Drive was released.
Cole just revealed the tracklist.
4 days #4YourEyezOnly @JColeNC @Dreamville pic.twitter.com/lyRVHoFgGr'ÄĒ Ibrahim H. (@KingOfQueenz) December 6, 2016
Neither of the two songs he dropped last week, 'Everybody Dies' and 'False Prophets', are on the 4 Your Eyes Only.
And, no, it doesn't have any features.
1. 'ÄúFor Whom the Bell Tolls'ÄĚ 2. 'ÄúImmortal'ÄĚ 3. 'ÄúDeja Vu'ÄĚ 4. 'ÄúVille Mentality'ÄĚ
5. 'ÄúShe Mine Pt. 1'Ä≥ 6. 'ÄúChange'ÄĚ 7. 'ÄúNeighbors'ÄĚ 8. 'ÄúFoldin'Äô Clothes'ÄĚ
9. 'ÄúShe Mine Pt. 2'Ä≥ 10. 'Äú4 Your Eyez Only'ÄĚ


text:
"I spent my life folded between the pages of books (…) My world is one interwoven web of words, stringing limb to limb, bone to sinew, thoughts and images all together. I am a being comprised of letters, a character created by sentences, a figment of imagination formed through fiction."
Tahereh Mafi
So, I am a girl from London who likes books. When I read, I mainly sway towards Fantasy and YA, but I do love dipping into all different kinds of genres. I share my reviews to a collective following of over five thousand followers on my Instagram, Goodreads and blog account, all of which are under the name of faerieontheshelf with the except of my Twitter, which is faeontheshelf.
My favourite authors are:
– Donna Tartt
– Angela Carter
– Madeline Miller
– Leigh Bardugo
– V.E. Schwab
– Maggie Stiefvater
– Katherine Arden
Some fun facts:
- The 'faerie' in my username doesn't refer to the cutesy Tinkerbell-like pint-sized fairy (I am not an overly cutesy person), but rather the traditional faeries from folklore, who are known as the fair folk – think of the fae from Sarah J. Maas and Holly Black books!
- I am a ENTP-T personality type, but I'm not so sure what that means either, really
- I am a Slytherin (hiss hiss)
- I own real estate in Velaris and am a happy member of the Night Court
- I'm also a morally ambiguous Grisha Heartrender
- If I lived in Westeros, I would fit right in as a Lady of House Tyrell


text:
I'm late to the party, but in the last year or so I have really got immersed into the world of podcasts.
There's a bit of a mix here from food, to fitness to health, but most have a sustainable twist!
Wellness Podcast with Liz Earle
I imagine most people with an interest in natural beauty will have heard of the Liz Earle skincare range. Little did I know she has a well being podcast amongst her many other projects. The podcast covers all sorts from organic farming, to gut health to gardening. Liz usually interviews a brand founder or public figure in the health and well being industry and asks interesting questions for an informative and enjoyable listen.
Talking Tastebuds with Venetia Falconer
This is a food based podcast by broadcaster Venetia Falconer. Venetia follows a vegan diet, so there is lots of talk on vegan eating and everything to do with food such as seasonal eating, diet trends and living consciously. I really like the guests Venetia has on. Some of my favourites include Anna Jones, author of Eating Seasonally, Dolly Alderton and The Happy Pear.
Get it on With Dawn O'Porter
This is a really great podcast that focus' all around style and fashion. Each podcast has a guest who talks about their personal style and what it means to them. It's really fascinating to see how other people view style, and the emotional effect it has on them. Clothes can have a really big affect on a person's confidence and can even affect how others perceive their personality. Dawn is a big fan of vintage clothing which I love! There's a great episode where Dawn interviews her husband Chris O'Dowd.
Plant Proof- Plant Based Nutrition & Inspiration
This is one of my newest finds. As the title suggests it is food based, talking around a plant based diet with different guests discussing their view point. Simon, the founder of the podcast has a great website with loads of information, recipes and guides. Definitely worth a check out!
Fit and Fearless
This podcast is in conjunction with Radio 5 Live and talks all about fitness, exercise, food and over all well being. Tally, Zanna and Vic – the 3 behind the Girl Gains movement, host the podcast with regular guests and discussions designed to inform and drive confidence. My favourite so far was the episode titled Easy Heath Hacks with Dr. Rangan Chatterjee.
Walking the Dog
I think I came across this podcast after I read about it in a magazine. Emily Deans, radio host and broadcaster talks to her famous pals out on a dog walk. Its light entertainment, with all manor of topics discussed from friends and families to current issues. Personally I liked finding out a bit more about David Gandy when he featured on the show!
The High Low
I listen to this podcast most weeks. Journalists Pandora Sykes and Dolly Alderton host a pop culture and current affairs. They discuss media they have consumed and talk openly and honestly about their feelings towards many topics including feminism, cultural issues and more light hearted topics such as fashion and food.
This is a brilliant podcast on environmental issues with a definite comedic twist! Topics such as population, global warming, plastic, anything really to do with helping the planet. Definitely a great way to try to understand some of the more complex issues in a lighthearted tone.
I really hope you like my recommendations. I am always on the lookout for new podcasts so please let me know if you can recommend any?


text:
@article {29730, title = {The Ventilation Problem in Schools: Literature Review}, journal = {Indoor Air}, volume = {27}, year = {2017}, month = {11/2017}, pages = {1039-1051}, abstract = {
Based on a review of literature published in refereed archival journals, ventilation rates in classrooms often fall far short of the minimum ventilation rates specified in standards. There is compelling evidence, from both cross-sectional and intervention studies, of an association of increased student performance with increased ventilation rates. There is evidence that reduced respiratory health effects and reduced student absence are associated with increased ventilation rates. Increasing ventilation rates in schools imposes energy costs and can increase heating, ventilating, and air-conditioning system capital costs. The net annual costs, ranging from a few dollars to about 10 dollars per person, are less than 0.1\% of typical public spending on elementary and secondary education in the United States. Such expenditures seem like a small price to pay given the evidence of health and performance benefits.}, keywords = {carbon dioxide, costs, health, performance, schools, ventilation}, issn = {0905-6947}, doi = {10.1111/ina.12403}, author = {William J. Fisk} } @article {61297, title = {Effects of ventilation rate per person and per floor area on perceived air quality, sick building syndrome symptoms, and decision-making}, journal = {Indoor Air}, volume = {25}, year = {2015}, month = {08/2015}, pages = {362-370}, publisher = {John Wiley \& Sons Ltd}, chapter = {362}, abstract = {
Ventilation rates (VRs) in buildings must adequately control indoor levels of pollutants; however, VRs are constrained by the energy costs. Experiments in a simulated office assessed the effects of VR per occupant on perceived air quality (PAQ), Sick Building Syndrome (SBS) symptoms, and decision-making performance. A parallel set of experiments assessed the effects of VR per unit floor area on the same outcomes. Sixteen blinded healthy young adult subjects participated in each study. Each exposure lasted four hours and each subject experienced two conditions in a within-subject study design. The order of presentation of test conditions, day of testing, and gender were balanced. Temperature, relative humidity, VRs, and concentrations of pollutants were monitored. Online surveys assessed PAQ and SBS symptoms and a validated computer-based tool measured decision-making performance. Neither changing the VR per person nor changing the VR per floor area, had consistent statistically significant effects on PAQ or SBS symptoms. However, reductions in either occupant-based VR or floor-area-based VR had a significant and independent negative impact on most decision-making measures. These results indicate that the changes in VR employed in the study influence performance of healthy young adults even when PAQ and SBS symptoms are unaffected.}, keywords = {Cognitive performance, Health symptoms, perceived air quality, ventilation}, doi = {10.1111/ina.12149}, author = {Randy L. Maddalena and Mark J. Mendell and Ekaterina Eliseeva and Wanyu R. Chan and Douglas P. Sullivan and Marion L. Russell and Usha Satish and William J. Fisk} } @article {59917, title = {Estimated effect of ventilation and filtration on chronic health risks in U.S. offices, schools, and retail stores}, year = {2015}, month = {02/2015}, abstract = {
We assessed the chronic health risks from inhalation exposure to volatile organic compounds (VOCs) and particulate matter (PM2.5) in U.S. offices, schools, grocery, and other retail stores and evaluated how chronic health risks were affected by changes in ventilation rates and air filtration efficiency. Representative concentrations of VOCs and PM2.5 were obtained from available data. Using a mass balance model, changes in exposure to VOCs and PM2.5 were predicted if ventilation rate were to increase or decrease by a factor of two, and if higher efficiency air filters were used. Indoor concentrations were compared to health guidelines to estimate percentage exceedances. The estimated chronic health risks associated with VOC and PM2.5 exposures in these buildings were low relative to the risks from exposures in homes. Chronic health risks were driven primarily by exposures to PM2.5 that were evaluated using disease incidence of mortality, chronic bronchitis, and non-fatal stroke. The leading cancer risk factor was exposure to formaldehyde. Using disability-adjusted life years (DALYs) to account for both cancer and non-cancer effects, results suggest that increasing ventilation alone is ineffective at reducing chronic health burdens. Other strategies, such as pollutant source control and the use of particle filtration, should also be considered.}, keywords = {commercial buildings, Disability-adjusted life years, Health risks, particulate matter, ventilation, volatile organic compounds}, doi = {10.1111/ina.12189}, author = {Wanyu R. Chan and Srinandini Parthasarathy and William J. Fisk and Thomas E. McKone} } @article {59666, title = {A simplified model for estimating population-scale energy impacts of building envelope air-tightening and mechanical ventilation retrofits}, journal = {Journal of Building Performance Simulation}, volume = {9}, number = {1-16}, year = {2015}, month = {01/2015}, publisher = {Journal of Building Performance Simulation}, abstract = {
Changing the air exchange rate of a home (the sum of the infiltration and mechanical ventilation airflow rates) affects the annual thermal conditioning energy. Large-scale changes to air exchange rates of the housing stock can significantly alter the residential sector{\textquoteright}s energy consumption. However, the complexity of existing residential energy models is a barrier to the accurate quantification of the impact of policy changes on a state or national level.
The Incremental Ventilation Energy (IVE) model developed in this study combines the output of simple air exchange models with a limited set of housing characteristics to estimate the associated change in energy demand of homes. The IVE model was designed specifically to enable modellers to use existing databases of housing characteristics to determine the impact of ventilation policy change on a population scale. The IVE model estimates of energy change when applied to US homes with limited parameterisation are shown to be comparable to the estimates of a well-validated, complex residential energy model.}, keywords = {air tightening, energy, policy, retrofit, ventilation, weatherization}, doi = {10.1080/19401493.2014.993710}, author = {Jennifer M. Logue and William J. N. Turner and Iain S. Walker and Brett C. Singer} } @article {59915, title = {Contaminant levels, source strengths, and ventilation rates in California retail stores}, journal = {Indoor Air}, volume = {25}, year = {2014}, month = {09/2014}, pages = {381-392}, chapter = {381}, abstract = {
This field study measured ventilation rates and indoor air quality in 21 visits to retail stores in California. Three types of stores, such as grocery, furniture/hardware stores, and apparel, were sampled. Ventilation rates measured using a tracer gas decay method exceeded the minimum requirement of California{\textquoteright}s Title 24 Standard in all but one store. Concentrations of volatile organic compounds (VOCs), ozone, and carbon dioxide measured indoors and outdoors were analyzed. Even though there was adequate ventilation according to standard, concentrations of formaldehyde and acetaldehyde exceeded the most stringent chronic health guidelines in many of the sampled stores. The whole-building emission rates of VOCs were estimated from the measured ventilation rates and the concentrations measured indoor and outdoor. Estimated formaldehyde emission rates suggest that retail stores would need to ventilate at levels far exceeding the current Title 24 requirement to lower indoor concentrations below California{\textquoteright}s stringent formaldehyde reference level. Given the high costs of providing ventilation, effective source control is an attractive alternative.}, keywords = {building energy efficiency standards, formaldehyde, ozone, ventilation, volatile organic compounds}, doi = {10.1111/ina.12152}, author = {Wanyu R. Chan and Sebastian Cohn and Meera A. Sidheswaran and Douglas P. Sullivan and William J. Fisk} } @article {56215, title = {Association of Classroom Ventilation with Reduced Illness Absence: A Prospective Study in California Elementary Schools}, journal = {Indoor Air}, volume = {23}, year = {2013}, month = {12/2013}, pages = {515-528}, chapter = {515}, abstract = {
Limited evidence associates inadequate classroom ventilation rates (VRs) with increased illness absence (IA). We investigated relationships between VRs and IA in California elementary schools over two school years in 162 3rd{\textendash}5th-grade classrooms in 28 schools in three school districts: South Coast (SC), Bay Area (BA), and Central Valley (CV). We estimated relationships between daily IA and VR (estimated from two year daily real-time carbon dioxide in each classroom) in zero-inflated negative binomial models. We also compared IA benefits and energy costs of increased VRs. All school districts had median VRs below the 7.1 l/s-person California standard. For each additional 1 l/s-person of VR, IA was reduced significantly (p\<0.05) in models for combined districts (-1.6\%) and for SC (-1.2\%), and nonsignificantly for districts providing less data: BA (-1.5\%) and CV (-1.0\%). Assuming associations were causal and generalizable, increasing classroom VRs from the California average (4 l/s-person) to the State standard would decrease IA by 3.4\%, increase attendance-linked funding to schools by $33 million annually, and increase costs by only $4 million. Further increasing VRs would provide additional benefits. These findings, while requiring confirmation, suggest that increasing classroom VRs above the State standard would substantially decrease illness absence and produce economic benefits.}, keywords = {carbon dioxide, Illness absence, indoor environmental quality, schools, ventilation}, doi = {10.1111/ina.12042}, author = {Mark J. Mendell and Ekaterina Eliseeva and Morris G. Davies and Michael Spears and Agnes B. Lobscheid and William J. Fisk and Michael G. Apte} } @article {57990, title = {Effect Of Ventilation On Chronic Health Risks In Schools And Offices}, year = {2013}, month = {01/2013}, abstract = {
This study provides a risk assessment for chronic health risks from inhalation exposure to indoor air pollutants in offices and schools with a focus how ventilation impacts exposures to, and risks from, volatile organic compounds (VOCs) and particulate matter (PM2.5). We estimate how much health risks could change with varying ventilation rates under two scenarios: (i) halving the measured ventilation rates and (ii) doubling the measured ventilation rates. For the hazard characterization we draw upon prior papers that identified pollutants potentially affecting health with indoor air concentrations responsive to changes in ventilation rates. For exposure assessment we determine representative concentrations of pollutants using data available in current literature and model changes in exposures with changes in ventilation rates. As a metric of disease burden, we use disability adjusted life years (DALYs) to address both cancer and non-cancer effects. We also compare exposures to guidelines published by regulatory agencies to assess chronic health risks. Chronic health risks are driven primarily by particulate matter exposure, with an estimated baseline disease burden of 150 DALYs per 100,000 people in offices and 140 DALYs per 100,000 people in schools. Study results show that PM2.5-related DALYs are not very sensitive to changes in ventilation rates. Filtration is more effective at controlling PM2.5 concentrations and health effects. Non-cancer health effects contribute only a small fraction of the overall chronic health burden of populations in offices and schools (\<1 DALY per 100,000 people). Cancer health effects dominate the disease burden in schools (3 DALYs per 100,000) and offices (5 DALYs per 100,000), with formaldehyde being the primary risk driver. In spite of large uncertainties in toxicological data and dose-response modeling, our results support the finding that ventilation rate changes do not have significant impacts on estimated chronic disease burdens. Median estimates of DALYs are approximately doubled when the ventilation rates are halved and there is little reduction in health risks associated with doubling ventilation rates, but the very low baseline disease burden from the indoor exposures we considered makes this unremarkable. In exploring the full range of exposure concentrations, to find the fraction exceeding the Office of Environmental Health and Hazard Assessment{\textquoteright}s (OEHHAs) chronic reference exposure levels (cRELs) and United States Environmental Protection Agency{\textquoteright}s (USEPA) chronic reference dose (RfD) we found only minor shifts in exposure safety margins when ventilation was doubled or halved. We combined our exposure estimates with cancer potency factors published by OEHHA and USEPA to determine that the annual excess cancer risk per capita are below 1 in a million under all ventilation rate scenarios for individual pollutants. The results indicate that chronic health risks (cancer and non-cancer) associated with VOC and PM2.5 exposure in offices and schools are low and thus the chronic disease burden or health benefits of ventilation changes are likely to be well below both the level of detection by health surveillance studies and the level of regulatory thresholds.}, keywords = {indoor air quality, ventilation}, author = {Srinandini Parthasarathy and William J. Fisk and Thomas E. McKone} } @article {57979, title = {Integrated Technology Air Cleaners (ITAC): Design and Evaluation}, year = {2013}, month = {09/2013}, abstract = {
The primary objective of this project was to design, build, and test an air cleaner for residential use with the potential to substantially improve indoor air quality, or maintain indoor air quality unchanged, when outdoor air ventilation rates are reduced to save energy. Two air cleaners were designed and fabricated. The design targets for airflow rate, fan power, and projected cost were met. In short term laboratory studies, both units performed as expected; however, during field studies in homes, the formaldehyde removal performance of the air cleaners was much lower than expected. In subsequent laboratory studies, incomplete decomposition of some indoor air volatile organic compounds, with formaldehyde as a product of partial decomposition of volatile organic compounds, was confirmed as the explanation for the poor formaldehyde removal performance in the field studies. The amount of formaldehyde produced per unit of decomposition of other volatile organic compounds was substantially diminished by increasing the amount of catalyst on the filter and also by decreasing the air velocity. Together, these two measures reduced formaldehyde production, per unit destruction of other volatile organic compounds, by a factor of four, while increasing the removal efficiency of volatile organic compounds by a factor of 1.4. A company with a southern California office is conducting studies in conjunction with Lawrence Berkeley National Laboratory, with the goal of incorporating the ITAC catalytic air cleaning technology in their future commercial products.}, keywords = {air cleaning, catalyst, energy efficiency, filtration, homes, ventilation}, author = {William J. Fisk and Sebastian Cohn and Hugo Destaillats and Victor Henzel and Meera A. Sidheswaran and Douglas P. Sullivan} } @article {3447, title = {Ventilation Control of Volatile Organic Compounds in New U.S. Homes: Results of a Controlled Field Study in Nine Residential Units}, year = {2013}, abstract = {
In order to optimize strategies to remove airborne contaminants in residences, it is necessary to determine how contaminant concentrations respond to changes in the air exchange rate. The impact of air exchange rate on the indoor concentrations of 39 target volatile organic compounds (VOCs) was assessed by measuring air exchange rates and VOC concentrations at three ventilation settings in nine residences. Active sampling methods were used for VOC concentration measurements, and passive perfluorocarbon tracer gas emitters with active sampling were used to determine the overall air exchange rate corresponding to the VOC measurements at each ventilation setting. The concentration levels and emission rates of the target VOCs varied by as much as two orders of magnitude across sites. Aldehyde and terpene compounds were typically the chemical classes with highest concentrations, followed by alkanes, aromatics, and siloxanes. For each home, VOC concentrations tended to decrease as the air exchange rate was increased, however, measurement uncertainty was significant. The indoor concentration was inversely proportional to air exchange rate for most compounds. For a subset of compounds including formaldehyde, however, the indoor concentration exhibited a non-linear dependence on the timescale for air exchange.}, keywords = {formaldehyde, residential, ventilation, vocs}, author = {Henry Willem and Erin L. Hult and Toshifumi Hotchi and Marion L. Russell and Randy L. Maddalena and Brett C. Singer} } @article {56218, title = {Is CO2 an Indoor Pollutant? Direct Effects of Low-to-Moderate CO2 Concentrations on Human Decision-Making Performance}, journal = {Environmental Health Perspectives}, volume = {120}, year = {2012}, month = {12/2012}, pages = {1671-1677}, chapter = {1671}, abstract = {
Associations of higher indoor carbon dioxide (CO2) concentrations with impaired work performance, increased health symptoms, and poorer perceived air quality have been attributed to correlation of indoor CO2 with concentrations of other indoor air pollutants that are also influenced by rates of outdoor-air ventilation.
We assessed direct effects of increased CO2, within the range of indoor concentrations, on decision making.
Twenty-two participants were exposed to CO2 at 600, 1,000, and 2,500 ppm in an office-like chamber, in six groups. Each group was exposed to these conditions in three 2.5-hr sessions, all on 1 day, with exposure order balanced across groups. At 600 ppm, CO2 came from outdoor air and participants{\textquoteright} respiration. Higher concentrations were achieved by injecting ultrapure CO2. Ventilation rate and temperature were constant. Under each condition, participants completed a computer-based test of decision-making performance as well as questionnaires on health symptoms and perceived air quality. Participants and the person administering the decision-making test were blinded to CO2 level. Data were analyzed with analysis of variance models.
Relative to 600 ppm, at 1,000 ppm CO2, moderate and statistically significant decrements occurred in six of nine scales of decision-making performance. At 2,500 ppm, large and statistically significant reductions occurred in seven scales of decision-making performance (raw score ratios, 0.06-0.56), but performance on the focused activity scale increased.
Direct adverse effects of CO2 on human performance may be economically important and may limit energy-saving reductions in outdoor air ventilation per person in buildings. Confirmation of these findings is needed.}, keywords = {carbon dioxide, cognition, Decision Making, human performance, indoor environmental quality, ventilation}, doi = {10.1289/ehp.1104789}, author = {Usha Satish and Mark J. Mendell and Krishnamurthy Shekhar and Toshifumi Hotchi and Douglas P. Sullivan and Siegfried Streufert and William J. Fisk} } @article {57553, title = {Demand Controlled Ventilation and Classroom Ventilation}, year = {2012}, month = {05/2012}, institution = {Lawrence Berkeley National Laboratory}, address = {Berkeley}, abstract = {
This document summarizes a research effort on demand controlled ventilation and classroom ventilation.
The research on demand controlled ventilation included field studies and building energy modeling. Major findings included:
The research on classroom ventilation collected data over two years on California elementary school classrooms to investigate associations between VRs and student illness absence (IA).
Major findings included:
This field study of 37 small and medium commercial buildings throughout California obtained information on ventilation rate, temperature, and heating, ventilating, and air-conditioning (HVAC) system characteristics. The study included seven retail establishments; five restaurants; eight offices; two each of gas stations, hair salons, healthcare facilities, grocery stores, dental offices, and fitness centers; and five other buildings. Fourteen (38\%) of the buildings either could not or did not provide outdoor air through the HVAC system. The air exchange rate averaged 1.6 (s.d. = 1.7) exchanges per hour and was similar between buildings with and without outdoor air supplied through the HVAC system, indicating that some buildings have significant leakage or ventilation through open windows and doors. Not all buildings had sufficient air exchange to meet ASHRAE 62.1 Standards, including buildings used for fitness centers, hair salons, offices, and retail establishments. The majority of the time, buildings were within the ASHRAE temperature comfort range. Offices were frequently overcooled in the summer. All of the buildings had filters, but over half the buildings had a filter with a minimum efficiency reporting value rating of 4 or lower, which are not very effective for removing fine particles. PRACTICAL IMPLICATIONS: Most U.S. commercial buildings (96\%) are small- to medium-sized, using nearly 18\% of the country{\textquoteright}s energy, and sheltering a large population daily. Little is known about the ventilation systems in these buildings. This study found a wide variety of ventilation conditions, with many buildings failing to meet relevant ventilation standards. Regulators may want to consider implementing more complete building inspections at commissioning and point of sale.}, keywords = {air exchange rate, commercial buildings, Heating, ventilating, and air-conditioning, thermal comfort, ventilation, ventilation standards}, doi = {10.1111/j.1600-0668.2012.00767.x}, author = {Deborah H. Bennett and William J. Fisk and Michael G. Apte and X. Wu and Amber L. Trout and David Faulkner and Douglas P. Sullivan} } @article {1912, title = {Measuring Outdoor Air Intake Rates into Existing Building-Final Report}, year = {2010}, month = {2010}, institution = {Lawrence Berkeley National Laboratory}, address = {Berkeley, CA}, abstract = {
Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10 percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15 percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100 percent, and were often greater than 25 percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems. The use of electronic velocity probes downstream of airflow straighteners is less promising, at least with the relatively small OA HVAC inlet systems employed in this research.}, keywords = {commercial building, control, hvac, measurement, outdoor air, ventilation}, author = {William J. Fisk and Douglas P. Sullivan and Sebastian Cohn and Hwataik Han} } @article {11492, title = {Are ventilation filters degrading indoor air quality in California classrooms?}, year = {2009}, institution = {Lawrence Berkeley National Laboratory}, address = {Berkeley, CA}, abstract = {
Heating, ventilating, and cooling classrooms in California consume substantial electrical energy. Indoor air quality (IAQ) in classrooms affects student health and performance. In addition to airborne pollutants that are emitted directly by indoor sources and those generated outdoors, secondary pollutants can be formed indoors by chemical reaction of ozone with other chemicals and materials. Filters are used in nearly all classroom heating, ventilation and air-conditioning (HVAC) systems to maintain energy-efficient HVAC performance and improve indoor air quality; however, recent evidence indicates that ozone reactions with filters may, in fact, be a source of secondary pollutants. This project quantitatively evaluated ozone deposition in HVAC filters and byproduct formation, and provided a preliminary assessment of the extent to which filter systems are degrading indoor air quality. The preliminary information obtained will contribute to the design of subsequent research efforts and the identification of energy efficient solutions that improve indoor air quality in classrooms and the health and performance of students.}, keywords = {acetaldehyde, filters, formaldehyde, hvac, ozone, secondary pollutants, ventilation, voc}, author = {Hugo Destaillats and Michael G. Apte and William J. Fisk} } @article {1871, title = {Measuring Outdoor Air Intake Rates Using Electronic Velocity Sensors at Louvers and Downstream of Airflow Straighteners}, year = {2008}, abstract = {
Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10 percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15 percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100 percent, and were often greater than 25 percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems. The use of electronic velocity probes downstream of airflow straighteners is less promising, at least with the relatively small OA HVAC inlet systems employed in this research.}, keywords = {Commercial Building Ventilation and Indoor Environmental Quality Group, commercial buildings, control, hvac, indoor environment department, measurements, outdoor air, ventilation, volatile organic compounds}, issn = {LBNL-1250E}, author = {William J. Fisk and Douglas P. Sullivan} } @article {10990, title = {CFD Investigation of Room Ventilation for Improved Operation of a Downdraft Table: Novel Concepts}, journal = {Journal of Occupational and Environmental Hygiene}, volume = {3}, number = {11}, year = {2006}, pages = {583-591}, chapter = {Chapter}, abstract = {
We report a computational fluid dynamics (CFD) study of containment of airborne hazardous materials in a ventilated room containing a downdraft table. Specifically, we investigate the containment of hazardous airborne material obtainable under a range of ventilation configurations. The desirable ventilation configuration should ensure excellent containment of the hazardous material released from the workspace above the downdraft table. However, increased airflow raises operation costs, so the airflow should be as low as feasible without compromising containment. The airflow is modeled using Reynolds Averaged Navier Stokes equations with a high Reynolds number k-epsilon turbulence model. CFD predictions are examined for several ventilation configurations. Based on this study, we find that substantial improvements in containment are possible concurrent with reduction in airflow, compared to the existing design of ventilation configuration.}, keywords = {airflow and pollutant transport group, cfd modeling, contamination control, downdraft table, indoor airflow and pollutant transport, indoor environment department, ventilation}, author = {Buvaneswari Jayaraman and Astrid H. Kristoffersen and Elizabeth U. Finlayson and Ashok J. Gadgil} } @proceedings {1772, title = {Indoor Environmental Risk Factors for Occupant Symptoms in 100 U.S. Office Buildings: Summary of Three Analyses from the EPA BASE Study}, journal = {Healthy Buildings 2006 Conference}, volume = {111}, year = {2006}, pages = {371-376}, chapter = {Chapter}, address = {Lisbon, Portugal}, abstract = {This paper summarizes three analyses of data on building-related environmental factors and occupant symptoms collected from 100 representative large U.S. office buildings. Using multivariate logistic regression models, we found increased occupant symptoms associated with a number of building-related factors, including lower ventilation rates even at the current guideline levels, lack of scheduled cleaning for air-conditioning drain pans and cooling coils, poor condition of cooling coils, poorly maintained humidification systems, and lower outdoor air intake height. Some expected relationships were not found, and several findings were opposite of expected. Although requiring replication, these findings suggest preventive actions to reduce occupant symptoms in office buildings.}, keywords = {building-related symptoms, indoor air quality, moisture, sick building syndrome, ventilation}, author = {Mark J. Mendell and Quanhong Lei-Gomez and Myrna Cozen and Howard S. Brightman and Michael G. Apte and Christine A. Erdmann and Gregory Brunner and John R. Girman} } @article {1671, title = {Some quantitative relations between Indoor environmental quality and work performance or health}, journal = {International Journal of HVAC\&R Research}, volume = {12}, number = {4}, year = {2006}, pages = {957-973}, chapter = {Chapter}, abstract = {Poor indoor environmental quality (IEQ) has been related to increases in sick building syndrome symptoms, respiratory illnesses, sick leave, and losses in productivity. Calculations indicate that the cost of poor IEQ can be higher than energy costs space conditioning and ventilation, and that many measures taken to improve indoor IEQ will be highly cost-effective when accounting for the monetary savings resulting from an improved health or productivity. To enable building professionals to make selections of building designs and operating practices that account for effects on health and productivity, we need models for quantifying the health and productivity benefits of better indoor environments. Therefore, we have reviewed the literature on the effects of indoor environment on health and performance and used existing data, when possible, to develop some initial models. Based on the best-available evidence we present quantitative relationships between ventilation rate and short term sick leave, ventilation rate and work performance, perceived air quality and performance, temperature and performance, and temperature and sick building syndrome symptoms. We show also that a relationship exists between SBS symptoms (sick building syndrome symptoms) and work performance.}, keywords = {Commercial Building Ventilation and Indoor Environmental Quality Group, cost benefit calculations, health and productivity effects, indoor environment department, modeling, perceived air quality, performance, sbs symptoms, temperature, ventilation}, author = {Olli Sepp{\"a}nen and William J. Fisk} } @proceedings {1802, title = {Estimated Ventilation Rates and Work-Related Symptoms in U.S. Office Buildings - The Base Study}, journal = {10th International Conference on Indoor Air Quality and Climate}, volume = {5(6)}, year = {2005}, month = {2005}, pages = {3758-3762}, publisher = {Tsinghua University Press}, chapter = {Chapter}, address = {Beijing, China}, abstract = {
Insufficient information has been available on measured ventilation rates and symptoms in office workers. Using U.S. EPA data from 100 large U.S. office buildings, we assessed relationships in multivariate models between ventilation/person and lower respiratory and mucous membrane symptoms. Three preliminary ventilation estimates were used, based on CO2 ratio in airstreams, peak indoor CO2 concentrations, and volumetric estimates of flow rates. Ventilation rates (VRs) from 6-17 cfm/person above the current 20 cfm/person guideline for offices were associated generally with reduced symptom prevalence, but further benefits were not evident from higher VRs. For all ventilation estimates, higher occupant density was independently associated with more symptoms. Findings suggest that VRs somewhat above current guidelines would reduce symptoms in office workers, and that occupant density may play an unrecognized role in ventilation requirements. Different findings for the various ventilation estimates were surprising. Clarification of these relationships, and validation of VR measurement methods are necessary.}, keywords = {Commercial Building Ventilation and Indoor Environmental Quality Group, health and productivity effects, indoor air quality, indoor environment department, office workers, respiratory symptoms, symptoms, ventilation, ventilation and air cleaning}, author = {Mark J. Mendell and Quanhong Lei-Gomez and Michael G. Apte and William J. Fisk}, editor = {Quanhong Lei} } @article {11390, title = {Evaluation of Ultra-Violet Photocatalytic Oxidation (UVPCO) for Indoor Air Applications: Conversion of Volatile Organic}, year = {2005}, note = {
This report was presented at\ Proceedings of Healthy Buildings 2006 Conference in Lisbon, Portugal. Volume 2. Pagination 243-248.
Abstract for conference proceedings: This paper summarizes three analyses of data on building-related environmental factors and occupant symptoms collected from 100 representative large U.S. office buildings. Using multivariate logistic regression models, we found increased occupant symptoms associated with a number of building-related factors, including lower ventilation rates even at the current guideline levels, lack of scheduled cleaning for air-conditioning drain pans and cooling coils, poor condition of cooling coils, poorly maintained humidification systems, and lower outdoor air intake height. Some expected relationships were not found, and several findings were opposite of expected. Although requiring replication, these findings suggest preventive actions to reduce occupant symptoms in office buildings.}, institution = {Lawrence Berkeley National Laboratory}, chapter = {Chapter}, abstract = {
Efficient removal of indoor generated airborne particles and volatile organic compounds (VOCs) in office buildings and other large buildings may allow for a reduction in outdoor air supply rates with concomitant energy savings while still maintaining acceptable indoor air quality in these buildings. Ultra-Violet Photocatalytic Oxidation (UVPCO) air cleaners have the potential to achieve the necessary reductions in indoor VOC concentrations at relatively low cost. In this study, laboratory experiments were conducted with a scaled, prototype UVPCO device designed for use in a duct system. The experimental UVPCO contained two 30 by 30-cm honeycomb monoliths coated with titanium dioxide and 3\% by weight tungsten oxide. The monoliths were irradiated with 12 UVC lamps arranged in four banks. The UVPCO was challenged with four mixtures of VOCs typical of mixtures encountered in indoor air. A synthetic office mixture contained 27 VOCs commonly measured in office buildings. A cleaning product mixture contained three cleaning products with high market shares. A building product mixture was created by combining sources including painted wallboard, composite wood products, carpet systems, and vinyl flooring. A fourth mixture contained formaldehyde and acetaldehyde. Steady-state concentrations were produced in a classroom laboratory or a 20-m3 environmental chamber. Air was drawn through the UVPCO, and single pass conversion efficiencies were measured from replicate air samples collected upstream and downstream of the reactor section. Concentrations of the mixtures were manipulated, with concentrations of individual VOCs mostly maintained below 10 ppb. Device flow rates were varied between 165 and 580 m3/h. Production of formaldehyde, acetaldehyde, acetone, formic acid, and acetic acid as reaction products was investigated. Conversion efficiency data were generated for 48 individual VOCs or groups of closely related compounds. Alcohols and glycol ethers were the most reactive chemical classes with conversion efficiencies often near or above 70\% at the low flow rate and near 40\% at the high flow rate. Ketones and terpene hydrocarbons were somewhat less reactive. The relative VOC conversion rates are generally favorable for treatment of indoor air since many contemporary products used in buildings employ oxygenated solvents. A commercial UVPCO device likely would be installed in the supply air stream of a building and operated to treat both outdoor and recirculated air. Assuming a recirculation rate comparable to three times the normal outdoor air supply rate, simple mass-balance modeling suggests that a device with similar characteristics to the study unit has sufficient conversion efficiencies for most VOCs to compensate for a 50\% reduction in outdoor air supply without substantially impacting indoor VOC concentrations. Formaldehyde, acetaldehyde, acetone, formic acid, and acetic acid were produced in these experiments as reaction byproducts. No other significant byproducts were observed. A coupled steady-state mass balance model is presented and applied to VOC data from a study of a single office building. For the operating assumptions described above, the model estimated a three-fold increase in indoor formaldehyde and acetaldehyde concentrations. The outcome of this limited assessment suggests that evaluation of the potential effects of the operation of a UVPCO device on indoor concentrations of these contaminants is warranted. Other suggested studies include determining VOC conversion efficiencies in actual buildings and evaluating changes in VOC conversion efficiency as monoliths age with long-term operation.}, keywords = {building-related symptoms, indoor air quality, moisture, sick building syndrome, ventilation}, author = {Alfred T. Hodgson and Douglas P. Sullivan and William J. Fisk} } @proceedings {1805, title = {Improving Relocatable Classroom HVAC For Improved IEQ And Energy Efficiency}, journal = {Indoor Air 2005 Conference - The 10th International Conference on Indoor Air Quality and Climate}, volume = {1}, year = {2005}, pages = {1121-1125}, publisher = {Tsinghua University Press}, edition = {7}, chapter = {Chapter}, address = {Beijing, China}, abstract = {
Relocatable classrooms (RCs) in California (CA) alone house about 2 million students in more than 80,000 structures. These buildings are typically under-ventilated, often due to low HVAC utilization because of excessive HVAC acoustic noise, and because when automatically operated they only ventilate during thermal conditioning. It can be predicted that such conditions affect the quality education and student health. These systems are also energy inefficient and peak-load demanding. With a manufacturer of wall-mounted HVAC systems, we are developing a new system addressing these problems. Design goals include a >=30\% increase the seasonal energy efficiency ratio (SEER) over the current SEER 10 system, noise reduction <=45 dB(A), continuous ventilation meeting CA State code requirements (e.g. ASHRAE 62.1 ventilation standard of 7 l s-1 per occupant and a pre-occupancy air purge). The prototype was operated in an RC test-bed to characterize its performance from the standpoint of ventilation, and thermal control, acoustical noise, and energy consumption. Ten of the new HVAC systems are also being monitored for one year in matched pairs with the current standard HVAC systems after being installed in identical occupied RCs in four schools in Northern and Southern CA. Continuous measurements include indoor and outdoor carbon dioxide, temperature, relative humidity, and HVAC power consumption. Additionally, acoustical noise levels; thermal comfort; and concentrations of volatile organic compounds, formaldehyde and acetaldehyde, and ozone will be measured on a regular schedule throughout the study year. Daily classroom occupancy rates will be collected from the class records. The potential IEQ and energy savings benefits of the system will be presented from preliminary data collected in the field.}, keywords = {acoustics, Commercial Building Ventilation and Indoor Environmental Quality Group, energy retrofits and diagnostics, field study, indoor environment department, indoor environmental quality, thermal conditioning, ventilation, ventilation and air cleaning}, author = {Michael G. Apte and David Faulkner and William J. Fisk and Alfred T. Hodgson and Toshifumi Hotchi and Chi-Ming Lai and Michael Spears and Douglas P. Sullivan and Duo Wang} } @proceedings {11252, title = {Investigation of Room Ventilation for Improved Operation of a Downdraft Table}, journal = {Proceedings of The 10th International Conference on Indoor Air Quality and Climate - Indoor Air 2005}, volume = {3(1)}, year = {2005}, pages = {2575-2579}, publisher = {Tsinghua University Press}, chapter = {Chapter}, address = {Beijing, China}, abstract = {
This paper reports a computational fluid dynamics (CFD) study on containment of airborne hazardous materials in a ventilated room containing a downdraft table. Specifically, we investigated the containment of hazardous airborne material under a range of ventilation configurations. The desirable ventilation configuration should ensure excellent containment of the hazardous material released from the workspace above the downdraft table. However, increased airflow raises operation costs, so the airflow should be as low as feasible without compromising containment. The airflow was modeled using Reynolds Averaged Navier Stokes equations with a high Reynolds number k-epsilon turbulence model using the commercial CFD code StarCD. CFD predictions were examined for several ventilation configurations. Based on this study, we found that substantial improvements in containment were possible with a significant reduction in airflow, compared to the existing ventilation configuration.}, keywords = {airflow and pollutant transport group, cfd modeling, contamination control, downdraft table, indoor airflow and pollutant transport, indoor environment department, ventilation}, author = {Buvaneswari Jayaraman and Astrid H. Kristoffersen and Elizabeth U. Finlayson and Ashok J. Gadgil} } @article {1670, title = {A model to estimate the cost effectiveness of indoor environment improvements in office work}, journal = {ASHRAE Transactions}, volume = {111}, number = {2}, year = {2005}, pages = {663-679}, chapter = {Chapter}, abstract = {
Deteriorated indoor climate is commonly related to increases in sick building syndrome symptoms, respiratory illnesses, sick leave, reduced comfort and losses in productivity. The cost of deteriorated indoor climate for the society is high. Some calculations show that the cost is higher than the heating energy costs of the same buildings. Also building-level calculations have shown that many measures taken to improve indoor air quality and climate are cost-effective when the potential monetary savings resulting from an improved indoor climate are included as benefits gained. As an initial step towards systemizing these building level calculations we have developed a conceptual model to estimate the cost-effectiveness of various measures. The model shows the links between the improvements in the indoor environment and the following potential financial benefits: reduced medical care cost, reduced sick leave, better performance of work, lower turn over of employees, and lower cost of building maintenance due to fewer complaints about indoor air quality and climate. The pathways to these potential benefits from changes in building technology and practices go via several human responses to the indoor environment such as infectious diseases, allergies and asthma, sick building syndrome symptoms, perceived air quality, and thermal environment. The model also includes the annual cost of investments, operation costs, and cost savings of improved indoor climate. The conceptual model illustrates how various factors are linked to each other. SBS symptoms are probably the most commonly assessed health responses in IEQ studies and have been linked to several characteristics of buildings and IEQ. While the available evidence indicates that SBS symptoms can affect these outcomes and suggests that such a linkage exists, at present we can not quantify the relationships sufficiently for cost-benefit modeling. New research and analyses of existing data to quantify the financial importance of SBS symptoms would enable more widespread consideration of the effects of IEQ in cost benefit calculations.}, keywords = {benefits, Commercial Building Ventilation and Indoor Environmental Quality Group, costs, health and productivity effects, indoor environment, indoor environment department, modeling, productivity, sbs-symptoms, sick leave, thermal environment, ventilation}, author = {Olli Sepp{\"a}nen and William J. Fisk} } @article {1879, title = {Outdoor Air Ventilation and Work-Related Symptoms in U.S. Office Buildings - Results from the Base Study}, year = {2005}, institution = {Lawrence Berkeley National Laboratory}, chapter = {Chapter}, abstract = {
Background: Recommendations for outdoor air ventilation rates in office buildings balance the need to dilute indoor pollutants for both health and comfort of the occupants against the costs of thermally conditioning the outdoor air. Although little scientific information has been available on the relationships between measured ventilation rates and health symptoms in office workers, a recently collected data set allows investigation of these relationships.
Methods: We performed analyses using data on work-related symptoms and ventilation rates collected by the U.S. EPA from a representative sample of 100 large U.S. office buildings {\textemdash} the Building Assessment and Survey Evaluation (BASE) study. Using multivariate logistic regression models for building-related lower respiratory and mucous membrane irritation symptoms, we estimated relative risks, as odds ratios, for three methods of estimating ventilation rate/person, adjusted for occupancy density and other confounders. The three ventilation rate measurement methods were based on CO2 ratio in airstreams, peak CO2 concentrations indoors, and volumetric estimates of flow rates.
Results: We found a general but irregular association of lower symptom prevalence with ventilation rates above the current recommended minimum for office space (about 20 cfm/person), but found no evidence for further increased benefits as ventilation rates continued to increase above 26, 32, or 37 cfm/person (depending on the measurement method). This relationship, however, did not hold for the volumetric method and lower respiratory symptoms. Also, for all measurement methods, even with ventilation per person held constant, medium to high occupancy density was associated with more symptoms than low occupancy density.
Discussion: These findings suggest, although not with complete consistency, that raising ventilation rates above current recommendations would reduce symptoms in office workers. The inconsistent findings for different measurement methods of ventilation were surprising. Occupancy density may play an unrecognized role in ventilation requirements. Further clarification of these relationships is necessary, as is the validation of accurate methods for measuring ventilation rates.}, keywords = {Commercial Building Ventilation and Indoor Environmental Quality Group, health and productivity effects, indoor air quality, indoor environment department, office workers, respiratory symptoms, symptoms, ventilation, ventilation and air cleaning}, author = {Mark J. Mendell and Quanhong Lei-Gomez and Michael G. Apte and William J. Fisk}, editor = {Quanhong Lei} } @article {1649, title = {Associations of Indoor Carbon Dioxide Concentrations and Environmental Susceptibilities with Mucous Membrane and Lower Respiratory Building Related Symptoms in the BASE Study: Analyses of the 100 Building Dataset}, journal = {Indoor Air}, volume = {14}, year = {2004}, month = {12/2004}, pages = {127-134}, abstract = {
Using the U.S. EPA 100 office-building BASE Study dataset, we conducted multivariate logistic regression analyses to quantify the relationship between indoor CO2 concentrations (dCO2) and mucous membrane (MM) and lower respiratory system (LResp) building related symptoms, adjusting for age, sex, smoking status, presence of carpet in workspace, thermal exposure, relative humidity, and a marker for entrained automobile exhaust. In addition, we tested the hypothesis that certain environmentally-mediated health conditions (e.g., allergies and asthma) confer increased susceptibility to building related symptoms within office buildings. Adjusted odds ratios (ORs) for statistically significant, dose-dependant associations (p \< 0.05) for dry eyes, sore throat, nose/sinus congestion, and wheeze symptoms with 100 ppm increases in dCO2 ranged from 1.1 to 1.2. These results suggest that increases in the ventilation rates per person among typical office buildings will, on average, reduce the prevalence of several building related symptoms by up to 70\%, even when these buildings meet the existing ASHRAE ventilation standards for office buildings. Building occupants with certain environmentally-mediated health conditions are more likely to experience building related symptoms than those without these conditions (statistically significant ORs ranged from 2 to 11).}, keywords = {BASE study, Building related symptoms, carbon dioxide, indoor environmental quality, sick building syndrome, ventilation}, doi = {10.1111/j.1600-0668.2004.00298.x}, author = {Christine A. Erdmann and Michael G. Apte} } @article {1704, title = {Environmental Tobacco Smoke Leakage from Smoking Rooms}, journal = {Journal of Occupational and Environmental Hygiene}, volume = {1}, year = {2004}, month = {02/2004}, pages = {110-118}, chapter = {110}, abstract = {
Twenty-seven laboratory experiments were conducted in a simulated smoking room to quantify rates of environmental tobacco smoke (ETS) leakage to a non-smoking area as a function of the physical and operational characteristics of the smoking room. Data are presented for the various types of leakage flows, the effect of these leaks on smoking room performance and non-smoker exposure, and the relative importance of each leakage mechanism. The results indicate that the first priority for an effective smoking room is to maintain it depressurized with respect to adjoining non-smoking areas. The amount of ETS pumped out by the smoking room door when it is opened and closed can be reduced significantly by substituting a sliding door for the standard swing-type door. An "open doorway" configuration used twice the ventilation flow as those with smoking room doors, but yielded less reduction in non-smoker exposure. Measured results correlated well with results modeled with mass-balance equations (R2 = 0.82-0.99). Most of these results are based on sulfur hexafluoride (SF6) tracer gas leakage. Because five measured ETS tracers showed good correlation with SF6, these conclusions should apply to ETS leakage as well. Field tests of a designated smoking room in an office building qualitatively agreed with model predictions.}, keywords = {designated smoking rooms, environmental tobacco smoke, exposure assess- ment, indoor air quality, ventilation}, issn = {1545-9624 (Print); 1545-9632 (Online)}, doi = {10.1080/15459620490275902}, author = {Jeff Wagner and Douglas P. Sullivan and David Faulkner and William J. Fisk and Leon E. Alevantis and Raymond L. Dod and Lara A. Gundel and Jed M. Waldman} } @conference {1781, title = {Energy and Indoor Environmental Quality in Relocatable Classrooms}, booktitle = {Indoor Air 2002, 9th International Conference on Indoor Air Quality and Climate}, volume = {II}, year = {2002}, pages = {62-69}, chapter = {Chapter}, address = {Monterey, CA}, abstract = {
Relocatable classrooms (RCs) are commonly utilized by school districts with changing demographics and enrollment sizes. Four energy-efficient RCs were designed and constructed for this study to demonstrate technologies that simultaneously attempt to improve energy efficiency and indoor environmental quality (IEQ). Two were installed at each of two school districts, and energy use and IEQ parameters were monitored during occupancy. Two (one per school) were finished with materials selected for reduced emissions of toxic and odorous volatile organic compounds (VOCs). Each RC had two HVAC systems, alternated weekly, consisting of a standard heat-pump system and an indirect-direct evaporative cooling (IDEC) system with gas-fired hydronic heating. The hypothesized advantages of the IDEC include continuous outside air ventilation at >=7.5 L s-1 per person, ~70\% less cooling energy and efficient particle filtration. Measurements include: carbon dioxide, particles, VOCs, temperature, humidity, thermal comfort, noise, meteorology, and energy use. Preliminary IEQ monitoring results are reported.}, keywords = {energy, indoor pollutants, schools, thermal comfort, ventilation}, author = {Michael G. Apte and Alfred T. Hodgson and Derek G. Shendell and Dennis L. DiBartolomeo and Toshifumi Hotchi and Satish Kumar and Seung-Min Lee and Shawna M. Liff and Leo I. Rainer and Richard C. Schmidt and Douglas P. Sullivan and Richard C. Diamond and William J. Fisk} } @conference {1761, title = {Indoor Carbon Dioxide Concentrations and Sick Building Syndrome Symptoms in the Base Study Revisited: Analyses of the 100 Building Dataset}, booktitle = {Indoor Air 2002, June 30 - July 5, 2002}, volume = {3}, year = {2002}, pages = {443-448}, chapter = {Chapter}, address = {Monterey, CA}, abstract = {
In previously published analyses of the 41-building 1994-1996 USEPA Building Assessment Survey and Evaluation (BASE) dataset, higher workday time-averaged indoor minus outdoor CO2 concentrations (dCO2) were associated with increased prevalence of certain mucous membrane and lower respiratory sick building syndrome (SBS) symptoms, even at peak dCO2 concentrations below 1,000 ppm. For this paper, similar analyses were performed using the larger 100-building 1994-1998 BASE dataset. Multivariate logistic regression analyses quantified the associations between dCO2 and the SBS symptoms, adjusting for age, sex, smoking status, presence of carpet in workspace, thermal exposure, relative humidity, and a marker for entrained automobile exhaust. Adjusted dCO2 prevalence odds ratios for sore throat and wheeze were 1.17 and 1.20 per 100-ppm increase in dCO2 (p \<0.05), respectively. These new analyses generally support our prior findings. Regional differences in climate, building design, and operation may account for some of the differences observed in analyses of the two datasets.}, keywords = {BASE study, carbon dioxide, Logistic regression, sick building syndrome, ventilation}, author = {Christine A. Erdmann and Kate C. Steiner and Michael G. Apte} } @article {30513, title = {Indoor Carbon Dioxide Concentrations, VOCs, Environmental Sensitivity Association with Mucous Membrane and Lower Respiratory Sick Building Syndrome Symptoms in the Base Study: Analyses of the 100 Building Dataset}, year = {2002}, month = {10/2002}, abstract = {
Using the 100 office-building Building Assessment Survey and Evaluation (BASE) Study dataset, we performed multivariate logistic regression analyses to quantify the associations between indoor minus outdoor CO2 (dCO2) concentrations and mucous membrane (MM) and lower respiratory system (Lresp) Sick Building Syndrome (SBS) symptoms, adjusting for age, sex, smoking status, presence of carpet in workspace, thermal exposure, relative humidity, and a marker for entrained automobile exhaust. Using principal components analysis we identified a number of possible sources of 73 measured volatile organic compounds in the office buildings, and assessed the impact of these VOCs on the probability of presenting the SBS symptoms. Additionally we included analysis adjusting for the risks for predisposition of having SBS symptoms associated with the allergic, asthmatic, and environmentally sensitive subpopulations within the office buildings. Adjusted odds ratios (ORs) for statistically significant, dose-dependant associations (p\<0.05) for dry eyes, sore throat, nose/sinus congestion, and wheeze symptoms with 100-ppm increases in dCO2 ranged from 1.1 to 1.2. These results suggest that increases in the ventilation rates per person among typical office buildings will, on average significantly reduce the prevalence of several SBS symptoms, up to 80\%, even when these buildings meet the existing ASHRAE ventilation standards for office buildings. VOC sources were observed to play an role in direct association with mucous membrane and lower respiratory irritation, and possibly to be indirectly involved in indoor chemical reactions with ozone that produce irritating compounds associated with SBS symptoms. O-xylene, possibly emitted from furniture coatings was associated with shortness of breath (OR at the maximum concentration = 8, p \< 0.05). The environmental sensitivities of a large subset of the office building population add to the overall risk of SBS symptoms (ORs ranging from 2 to above 11) within the buildings.}, keywords = {BASE study, carbon dioxide, Logistic regression, sick building syndrome, ventilation}, author = {Michael G. Apte and Christine A. Erdmann} } @proceedings {1800, title = {Measurements And Modeling Of Environmental Tobacco Smoke Leakage From A Simulated Smoking Room}, journal = {Proceedings of the Indoor Air 2002 Conference, Monterey, CA}, volume = {2}, year = {2002}, pages = {121-126}, publisher = {Indoor Air 2002, Santa Cruz, CA}, chapter = {Chapter}, abstract = {
The purpose of this study is to quantify the effect of various design and operating parameters on smoking room performance. Twenty-eight experiments were conducted in a simulated smoking room with a smoking machine and an automatic door opener. Measurements were made of air flows, pressures, temperatures, two particle-phase ETS tracers, two gas-phase ETS tracers, and sulfur hexafluoride. Quantification of leakage flows, the effect of these leaks on smoking room performance and non-smoker exposure, and the relative importance of each leakage mechanism are presented. The results indicate that the first priority for an effective smoking room is to depressurize it with respect to adjoining non-smoking areas. Another important ETS leakage mechanism is the pumping action of the smoking room door. Substituting a sliding door for a standard swing-type door reduced this source of ETS leakage significantly. Measured results correlated well with model predictions (R2 = 0.82-0.99).}, keywords = {Chamber studies, environmental tobacco smoke, nicotine, Smoking room, ventilation}, author = {Jeff Wagner and Douglas P. Sullivan and David Faulkner and Lara A. Gundel and William J. Fisk and Leon E. Alevantis and Jed M. Waldman} } @conference {30514, title = {Indoor Carbon Dioxide Concentrations and SBS in Office Workers}, booktitle = {Healthy Buildings 2000, August 6-10, 2000}, year = {2000}, month = {08/2000}, address = {Espoo, Finland}, abstract = {
Relationships between indoor carbon dioxide (CO2) levels and mucous membrane and lower respiratory sick building syndrome (SBS) symptoms are explored in 41 office buildings from the US EPA BASE study. Elevated indoor CO2 concentrations may indicate inadequate ventilation per occupant and elevated indoor pollutant concentrations, leading to SBS symptoms. Two CO2 metrics were constructed: average workday indoor minus average outdoor CO2 (dCO2, range 6-418 ppm), and maximum indoor one-hour moving average CO2 minus outdoor CO2 concentrations (dCO2MAX). Multivariate logistic regressions quantified dCO2/SBS symptom associations, adjusting for personal and environmental factors. A dose-response relationship (p\<0.05) with odds ratios per 100 ppm dCO2 ranging from 1.2 to 1.5 for sore throat, nose/sinus, tight chest, and wheezing was observed. The dCO2MAX/SBS regression results were similar. Implications: large increases in ventilation rate or improvements in ventilation effectiveness and/or indoor pollutant source control would be expected to decrease the prevalence of selected symptoms by up to 70-85\%.}, keywords = {Dose-response, Logistic regression, sick building syndrome, ventilation}, author = {Michael G. Apte and William J. Fisk and Joan M. Daisey} } @article {10980, title = {Volatile Organic Compound Concentrations and Emission Rates in New Manufactured and Site-Built Houses}, journal = {Indoor Air}, volume = {10}, year = {2000}, month = {09/2000}, pages = {178-192}, chapter = {178}, abstract = {
Concentrations of 54 volatile organic compounds (VOCs) and ventilation rates were measured in four new manufactured houses over 2-9.5 months following installation and in seven new site-built houses 1-2 months after completion. The houses were in four projects located in hot-humid and mixed-humid climates. They were finished and operational, but unoccupied. Ventilation rates ranged from 0.14-0.78 h-1. Several of the site-built houses had ventilation rates below the ASHRAE recommended value. In both manufactured and site-built houses, the predominant airborne compounds were alpha-pinene, formaldehyde, hexanal, and acetic acid. Formaldehyde concentrations were below or near 50 ppb with a geometric mean value for all houses of 40 ppb. Similarities in the types of VOCs and in VOC concentrations indicated that indoor air quality in the houses was impacted by the same or similar sources. Major identified sources included plywood flooring, latex paint and sheet vinyl flooring. One site-built house was operated at ventilation rates of 0.14 and 0.32 h-1. VOC emission rates calculated at the two conditions agreed within +/- 10\% for the most volatile compounds. Generally, the ratios of emission rates at the low and high ventilation rates decreased with decreasing compound volatility. Changes in VOC emission rates in the manufactured houses over 2-9.5 months after installation varied by compound. Only several compounds showed a consistent decrease in emission rate over this period.}, keywords = {aldehydes, emissions, formaldehyde, Houses, ventilation, voc}, doi = {10.1034/j.1600-0668.2000.010003178.x}, author = {Alfred T. Hodgson and Armin F. Rudd and David Beal and Subrato Chandra} } @article {56302, title = {Enhanced particle filtration in a non-problem office environment: Preliminary results from a double-blind crossover intervention study}, journal = {American Journal of Industrial Medicine Supplement}, volume = {36}, year = {1999}, month = {09/1999}, pages = {55-57}, abstract = {
Workers in indoor environments often complain of symptoms, such as eye and nose irritation, headache, and fatigue, which improve away from work. Exposures causing such complaints, sometimes referred to as sick building syndrome, generally have not been identified. Evidence suggests these worker symptoms are related to chemical, microbiological, physical, and psychosocial exposures not well characterized by current methods [Mendell, 1993]. Most research in this area has involved cross-sectional studies, which are limited in their abilities to show causal connections. Experimental studies have also been conducted which, by changing one factor at a time to isolate its effects, can demonstrate benefits of an environmental intervention even before the exposures or mechanisms are understood [Mendell, 1993]. This study was prompted by the evidence that particulate contaminants may be related to acute occupant symptoms and discomfort [Mendell, 1993; Leinster, 1990]. The objective was to assess, with a double-blind, double crossover intervention design, whether improved removal of small airborne particles by enhanced central filtration would reduce symptoms and discomfort.}, keywords = {indoor air quality, intervention, occupational health and safety, sick building syndrome, ventilation, work environment, {\textregistered}ltration}, doi = {10.1002/(SICI)1097-0274(199909)36:1+<55::AID-AJIM20>3.0.CO;2-8}, author = {Mark J. Mendell and William J. Fisk and Maxia Dong and Marty R. Petersen and Cynthia J. Hines and David Faulkner and James A. Deddens and Avima M. Ruder and Douglas P. Sullivan and Mark F. Boeniger} } @conference {1790, title = {Ventilation Efficiencies of Desk-Mounted Task/Ambient Conditioning Systems}, booktitle = {Indoor Air {\textquoteright}99 Conference, August 8-13, 1999}, volume = {9}, year = {1999}, month = {08/1999}, pages = {273-281}, publisher = {Construction Research Communications, Ltd., London}, organization = {Construction Research Communications, Ltd., London}, chapter = {Chapter}, address = {Edinburgh, Scotland}, abstract = {
In laboratory experiments, we investigated two task/ambient conditioning systems with air supplied from desk-mounted air outlets to efficiently ventilate the breathing zone of heated manikins seated at desks. In most experiments, the task conditioning systems provided outside air while a conventional ventilation system provided additional space cooling but no outside air. Air change effectiveness (i.e., exhaust air age divided by age of air at the manikin{\textquoteright}s face) was measured with a tracer gas step-up procedure. Other tracer gases simulated the release of pollutants from nearby occupants and from the floor covering, and the associated pollutant removal efficiencies (i.e., exhaust air concentrations divided by concentrations at manikin{\textquoteright}s face) were calculated. High values of air change effectiveness (~ 1.3 to 1.9) and high values of pollutant removal efficiency (~ 1.2 to 1.6) were measured when these task conditioning systems supplied 100\% outdoor air at a flow rate of 7 to 9 L s-1 per occupant. Air change effectiveness was reasonably well correlated with the pollutant removal efficiency. Overall, the experimental data suggest that these task/ambient conditioning systems can be used to improve ventilation and air quality or to save energy while maintaining a typical level of IAQ at the breathing zone.}, keywords = {Air change effectiveness, indoor air quality, Pollutant removal efficiency, Task/Ambient conditioning, ventilation}, author = {David Faulkner and William J. Fisk and Douglas P. Sullivan and David P. Wyon} } @article {1662, title = {Elevated Symptom Prevalence Associated with Ventilation Type in Office Buildings}, journal = {Epidemiology}, volume = {7}, year = {1996}, month = {11/1996}, pages = {583-589}, abstract = {
The California Healthy Building Study was designed to assess relations between ventilation system type and office worker symptoms in a set of U.S. buildings selected without regard to worker complaints. Twelve public office buildings in northern California meeting specific eligibility criteria were studied in the summer of 1990: three naturally ventilated, three mechanically ventilated (without air conditioning), and six air-conditioned buildings. Questionnaire data were collected from 880 workers in selected spaces within the study buildings. We adjusted effect estimates for various ventilation types for personal, job, and work place factors using logistic regression, and alternatively, using a mixed effects model (SAS/GLIMMIX) to adjust for correlated responses within study spaces. Higher adjusted prevalences of most symptom outcomes were associated with both mechanical and air\conditioned ventilation, relative to natural. With a conservative adjustment for problem building status, the highest adjusted prevalence odds ratios from logistic regression models were for dry or itchy skin [mechanical: odds ratio (OR) = 6.0, 95\% confidence interval (CI) = 1.6-22; air\conditioned: OR = 6.0, 95\% CI = 1.7-21] and lower respiratory symptoms (mechanical: OR = 2.9, 95\% CI = 0.7-11; air\conditioned: OR = 4.0, 95\% CI = 1.1-15). GLIMMIX estimates were similar, with slightly wider confidence intervals. Reporting bias was small. These findings of symptom increases within mechanically ventilated and air-conditioned U.S. buildings support previous findings available only from European buildings. (Epidemiology 1966; 7:583-589)}, keywords = {indoor air pollution, sick building syndrome, ventilation}, url = {https://journals.lww.com/epidem/Citation/1996/11000/Elevated_Symptom_Prevalence_Associated_with.5.aspx}, author = {Mark J. Mendell and William J. Fisk and James A. Deddens and William G. Seavey and Allan H. Smith and Daniel F. Smith and Alfred T. Hodgson and Joan M. Daisey and Lynn R. Goldman} } @article {10984, title = {Mixing of a Point Source Indoor Pollutant by Forced Convection}, journal = {Indoor Air}, volume = {5}, year = {1995}, month = {09/1995}, pages = {204-215}, chapter = {204}, abstract = {
The mixing rate of pollutants emitted from indoor sources influences the effectiveness of pollutant removal by building ventilation and the potential variability of exposure for a given release scenario. Quantitative information is scant on the mixing rate and the factors that govern it. We present mixing data for an instantaneously released tracer gas, carbon monoxide, in a sealed, unoccupied room under a range of forced airflow conditions, in which the flow is induced by blowers. The resulting mixing times, from 2 to 42 minutes, are related to the mechanical power of the air jets produced by the blowers. Mixing times are found to correlate well with the inverse of the cube root of power, in accordance with theoretical predictions and experimental observations for mixing in chemical reactors. The exposure index, defined as the time-averaged concentration at a point relative to the time-averaged concentration for the room as a whole, is presented for three experimental conditions, yielding quantitative information on the appropriateness of the well-mixed hypothesis under various flow conditions. In general, the exposure period following instantaneous release of a point-source pollutant must be much greater than the mixing time for the assumption of uniform mixing to hold. The correlation between mixing time and power input is used to predict the mixing time from the mixing action of a supply air jet for a typical ventilation scenario. The predicted mixing time, τmix\~{}7 min, is substantially lower than the time scale for removal by ventilation, τvent\~{}48 min. Under these conditions, complete mixing of an instantaneous release, point-source pollutant would be approximately attained within the interior space well before the pollutant would be thoroughly removed by ventilation.}, keywords = {Forced convection, mixing, Natural convection, Tracer gas, ventilation}, doi = {10.1111/j.1600-0668.1995.t01-1-00007.x}, author = {Anushka C. Drescher and Cesare Lobascio and Ashok J. Gadgil and William W. Nazaroff} } @conference {30504, title = {Indoor Air Flow and Pollutant Removal in a Room With Desk-Top Ventilation}, booktitle = {1993 Annual Meeting of the American Society of Heating, Refrigerating, and Air Conditioning Engineers, June 26-30}, year = {1993}, month = {06/1993}, address = {Denver, Colorado}, abstract = {
In a furnished experimental facility with three workstations separated by partitions, we studied indoor air flow patterns and tobacco smoke removal efficiency of a desk-top task ventilation system. The task ventilation system permits occupant control of the temperature, flow rate and direction of air supplied through two desk-mounted supply nozzles. In the configuration evaluated, air exited the ventilated space through a ceiling-mounted return grill. To study indoor air flow patterns, we measured the age of air at multiple indoor locations using the tracer gas step-up procedure. To study the intra-room transport of tobacco smoke particles and the efficiency of particle removal by ventilation, a cigarette was smoked mechanically in one workstation and particle concentrations were measured at multiple indoor locations including the exhaust airstream. Test variables included the direction of air supply from the nozzles, supply nozzle area, supply flow rate and temperature, percent recirculation of chamber air, and internal heat loads.
Our major findings are as follows: (1) In tests with the nozzles pointed toward the occupants, 100\% outside air supplied at the desk-top, and air supply rates of approximately 85 cfm (40 L/s) per workstation, the age of air at the breathing level of ventilated workstations was approximately 30\% less than the age of air that would occur throughout the test space with perfectly mixed indoor air, (2) with smaller air supply rates and/or air supplied parallel to the edges of the desk, ages of air at breathing locations were not significantly lower than the age with perfect mixing, (3) indoor tobacco smoke particle concentrations at specific locations were generally within 12\% of the average measured indoor concentration and concentrations of particles in the exhaust airstream were not significantly different from concentration of particles at breathing locations.
Epidemiologic research into the causes of non-specific symptoms among office workers has produced a variety of conflicting findings which are difficult to synthesize. This paper first discusses methodologic issues important in the interpretation of epidemiologic studies, and then reviews the findings of 32 studies of 37 factors potentially related to office worker symptoms. Among environmental factors assessed, there were generally consistent findings associating increased symptoms with air-conditioning, carpets, more workers in a space, VDT use, and ventilation rates at or below 10 liters/second/person. Studies with particularly strong designs found decreased symptoms associated with low ventilation rate, short-term humidification, negative ionization, and improved office cleaning, although studies reviewed showed little consistency of findings for humidification and ionization. Relatively strong studies associated high temperature and low relative humidity with increased symptoms, whereas less strong studies were not consistent. Among personal factors assessed, there were generally consistent findings associating increased symptoms with female gender, job stress/dissatisfaction, and allergies/asthma. For other environmental or personal factors assessed, findings were too inconsistent or sparse for current interpretation, and there were no findings from strong studies. Overall evidence suggested that work related symptoms among office workers were relatively common, and that some of these symptoms represented preventable physiologic effects of environmental exposures or conditions. Future research on this problem should include blind experimental and case-control studies, using improved measurements of both environmental exposures and health outcomes.}, keywords = {Air-conditioning, health, indoor air quality, office buildings, sick building syndrome, ventilation}, doi = {10.1111/j.1600-0668.1993.00003.x}, author = {Mark J. Mendell} }


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Unite 12, Cattle Depot63 Ma Tau Kok Road, Hong Kong
牛棚12號單位馬頭角道63號, 香港
Chamber Opera "Two Ladies" - Talk about Xixi's A Girl like Me & The Cold
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Composer Daniel Lo and novelist Wong Yi have adapted Xixi's short stories A Girl Like Me and The Cold, and have been developing a chamber opera in Cantonese. Before the showcase on 24th March, the two creators will hold a reading session with scholar Wong Ka Ki to share their interpretations of the two novels and Xixi's influence in the 21st century. The speakers will analyze the two works and share the creative process of the opera script and libretto. Audience and enthusiast readers are welcome to share and discuss their thoughts on Xixi and her novels at this event.
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