Emission Standards ) 51  of the CAA. Therefore, although aircraft HAPs ar e not specifically  regulated under the CAA, they are indirectly controlled as elements of total hydrocarbons (HC) and PM.  In a related matter, the EPA has identified 21 HAPs that are designated as Mobile Source Air  Toxics (MSATs) 52  to signify those HAPs that are emitted by motor vehicles and non- road  engines (e.g., farm and construction equipment, heavy industrial vehicles, GSE, etc.). These  pollutants include VOCs and heavy metals that are commonly associated with the combustion of  gasoline and diesel fuels - including those emitted by aviation-related motor vehicles and GSE.  Other sources of HAPs associated with airports are similarly regulated under Section 112 of the  CAA if their emissions exceed established thresholds and they  meet the definition of a major  stationary or area source. These may include aircraft repair and maintenance facilities, engine  test cells, central heating plants, painting operations, and other airport support services generate air emissions.  In 2003, the FAA undertook  a review of publicly available information pertaining to relationship(s) between aircraft and  airport-related activities and the emissions of HAPs.  This  initial body of work focused on those emissions specifically identified by the EPA as HAPs and  was prepared in response to the rising interest by various federal, state and local governmental  agencies and the general public in connection with these pollutants. Referred  to as the  FAA  Resource Document for HAPs , this initial report was entitled and is described as follows:  In response to this need for more information, in 2009 the EPA and the FAA developed organic  gas (OG) speciation profiles and best practices for use in HAPs emission inventories of aircraft  equipped with turbofan, turbojet, and turboprop engines fueled  with kerosene-based jet-A fuel.  The development of these profiles and guidance was the combined work of both agencies, taking  into account the most recent data and information available.  Referred to as  the  Speciated  Organic Gas Emissions from Aircraft Guidance , this document is entitled and described follows:  51 CAA, Title II,  Part B – Aircraft Emission Standards (Sections 231 – 234) ,  http://www.epa.gov/air/caa/title2.html, and USC, Title 42, Chapter 85, Subchapter II,  Part B – Aircraft  Emission Standards (Sections 7571 – 7574) , http://www.gpo.gov/fdsys/pkg/USCODE-2010- title42/pdf/USCODE-2010-title42-chap85-subchapII-partB.pdf.  52  EPA,  Mobile Source Air Toxics , http://www.epa.gov/otaq/toxics.htm.  53  FAA,  Select Resource Materials and Annotated Bibliography on the Topic of Hazardous Air Pollutants (HAPs)  Associated With Aircraft, Airports and Aviation,  Technical Directive Memorandum D01-010, July 1, 2003,  http://www.faa.gov/regulations_policies/policy_guidance/envir_policy/media/HAPs_rpt.pdf.  45$_{ }$ Among the key findings from this initial publicatio n was the need for a more unified  approach and technical guidelines for evaluating HAPs emissions for  aviation-related  sources. Other topics include HAP types and sources, agency regulations, and monitoring data associated with airports and aviation.  • Select Resource Materials and Annotated Bibliography on the Topic of Hazardous Air  Pollutants (HAPs) Associated With Aircraft, Airports and Aviation. 53  6.2.2.  FAA Guidance  Aviation Emissions and Air Quality Handbook 