Journal
ENVIRONMENTAL POLLUTION
Volume 244, Issue -, Pages 84-92Publisher
ELSEVIER SCI LTD
DOI: 10.1016/j.envpol.2018.10.006
Keywords
Carbonaceous species; Relative humidity; Diurnal variation; Heterogeneous reaction
Categories
Funding
- National Science and Technology Program of China [2017YFC0211601, 2016YFC0202700]
- National Natural Science Foundation of China [81571130090]
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Organic aerosol (OA) are always the most abundant species in terms of relative proportion to PM2.5 concentration in Beijing, while in previous studies, poor link between carbonaceous particles and their gaseous precursors were established based on field observation results. Through this study, we provided a comprehensive analysis of critical carbonaceous species in the atmosphere. The concentrations, diurnal variations, conversions, and gas-particle partitioning (F-factor) of 8 carbonaceous species, carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), volatile organic compounds (VOCs), non-methane hydrocarbon (NMHC), organic carbon (OC), elemental carbon (EC), and water soluble organic compounds (WSOCs), in Beijing were analyzed synthetically. Carbonaceous gases (CO, CO2, VOCs, and CH4) and OC/EC ratios exhibited double-peak diurnal patterns with a pronounced midnight peak, especially in winter. High correlation between VOCs and OC during winter nighttime indicated that OC was formed from VOCs precursors via an unknown mechanism at relative humidity greater than 50% and 80%, thereby promoting WSOC formation in PM1 and PM2.5 respectively. The established F-factor method was effective to describe gas-to-particle transformation of carbonaceous species and was a good indicator for haze events since high F-factors corresponded with enhanced PM2.5 level. Moreover, higher F-factors in winter indicated carbonaceous species were more likely to exist as particles in Beijing. These results can help gain a comprehensive understanding of carbon cycle and formation of secondary organic aerosols from gaseous precursors in the atmosphere. (C) 2018 Published by Elsevier Ltd.
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