{'fraction_non_alphanumeric': 0.044753086419753084, 'fraction_numerical': 0.032407407407407406, 'mean_word_length': 5.485, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 1, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
[Characteristics and Reactivity of VOCs in Hangzhou During a Typical Photochemical Pollution Episode].

An intensive observation of ambient volatile organic compounds (VOCs) was carried out in Hangzhou, a key city in the Yangtze River Delta, during a typical photochemical pollution episode from September 14-23, 2018. The analysis results of 80 effective samples showed that the average concentration of 122 compounds of VOCs was (59.5±19.8)×10-9 during the observation period, and oxygenated VOCs (OVOCs) were the most abundant component. The assessment results of atmospheric reaction activity with ozone formation potential (OFP) showed that the average value of OFP was 145×10-9 during the observation period, of which alkenes and carbonyl compounds were the most abundant components. The chemical reactivity of VOCs in Hangzhou was equivalent to acrylonitrile. Based on the positive matrix factorization (PMF) model, five major sources of VOCs in Hangzhou were identified, including secondary formation (25.2%), combustion and industrial processing (27.2%), solvent use (17.3%), biogenic sources (9.2%), and vehicular exhaust (21.2%). The results can provide guidance for further understanding of VOC characteristics and the basis for scientific prevention and control measures in Hangzhou.