Insights on organic aerosol aging and the influence of coal combustion at a regional receptor site of central eastern China W. W. Hu1,*, M. Hu1, B. Yuan1,**, J. L. Jimenez3, Q. Tang1, J. F. Peng1, W. Hu1, M. Shao1, M. Wang1, L. M. Zeng1, Y. S. Wu1, Z. H. Gong1,2, X. F. Huang1,2, and L. Y. He1,2 1State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China 2Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055, China 3Cooperative Institute for Research in the Environmental Sciences (CIRES) and Department of Chemistry and Biochemistry, Univ. of Colorado, Boulder, CO, USA *now at: Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309, USA **now at: Earth System Research Laboratory, Chemical Sciences Division, NOAA, 325 Broadway, Boulder, Colorado 80305, USA
Abstract. In order to understand the aging and processing of organic aerosols (OA), an
intensive field campaign (Campaign of Air
Pollution at Typical Coastal
Areas IN Eastern China, CAPTAIN) was conducted
March–April at a receptor site (a Changdao island) in central eastern China.
Multiple fast aerosol and gas measurement instruments were used during the
campaign, including a high resolution time-of-flight aerosol mass
spectrometer (HR-ToF-AMS) that was applied to measure mass concentrations and
non-refractory chemical components of submicron particles (PM1nr).
The average mass concentration of PM1(PM1nr+black
carbon) was 47 ± 36 μg m−3 during the campaign and showed
distinct variation, depending on back trajectories and their overlap with
source regions. Organic aerosol (OA) is the largest component of PM1
(30%), followed by nitrate (28%), sulfate (19%), ammonium (15%),
black carbon (6%), and chloride (3%). Four OA components were resolved
by positive matrix factorization (PMF) of the high-resolution spectra,
including low-volatility oxygenated organic aerosol (LV-OOA), semi-volatile
oxygenated OA (SV-OOA), hydrocarbon-like OA (HOA) and a coal combustion OA
(CCOA). The mass spectrum of CCOA had high abundance of fragments from
polycyclic aromatic hydrocarbons (PAHs) (m/z 128, 152, 178, etc.). The average
atomic ratio of oxygen to carbon in OA (O / C) at Changdao was 0.59, which is
comparable to other field studies reported at locations downwind of large
pollution sources, indicating the oxidized nature of most OA during the
campaign. The evolution of OA elemental composition in the van Krevelen
diagram (H / C vs. O / C) showed a slope of −0.63; however, the OA influenced by
coal combustion exhibits a completely different evolution that appears
dominated by physical mixing. The aging of organic aerosols vs.
photochemical age was investigated. It was shown that OA / ΔCO, as well
as LV-OOA / ΔCO and SV-OOA / ΔCO, positively correlated with
photochemical age. LV-OOA accounted for 73% of the OA secondary formation
(SOA) in the oldest plumes (photochemical age of 25 h). The kOH at
Changdao, by assuming SOA formation and aging as a first-order process
proportional to OH, was calculated to be 5.2 × 10−12 cm3 molec.−1 s−1, which is similar to those determined
in recent studies of polluted air in other continents.
Citation: Hu, W. W., Hu, M., Yuan, B., Jimenez, J. L., Tang, Q., Peng, J. F., Hu, W., Shao, M., Wang, M., Zeng, L. M., Wu, Y. S., Gong, Z. H., Huang, X. F., and He, L. Y.: Insights on organic aerosol aging and the influence of coal combustion at a regional receptor site of central eastern China, Atmos. Chem. Phys., 13, 10095-10112, doi:10.5194/acp-13-10095-2013, 2013.