TY - JOUR
T1 - Characteristics, sources and evolution processes of atmospheric organic aerosols at a roadside site in Hong Kong
AU - Yao, Dawen
AU - Lyu, Xiaopu
AU - Lu, Haoxian
AU - Zeng, Lewei
AU - Liu, Tengyu
AU - Chan, Chak K.
AU - Guo, Hai
N1 - Funding Information:
This study was supported by the Research Grants Council of the Hong Kong Special Administrative Region via Theme-Based Research Scheme (Project T24-504/17-N) and General Research Fund (PolyU 152052/16 E), and the Strategic Focus Area scheme of The Research Institute for Sustainable Urban Development at The Hong Kong Polytechnic University (1-BBW9), and the Hong Kong Polytechnic University internal fund (4-BCF6).
Publisher Copyright:
© 2021 Elsevier Ltd
PY - 2021/5
Y1 - 2021/5
N2 - A sampling campaign was conducted at an urban roadside site in Hong Kong from Nov. to Dec. in 2017 using a suite of state-of-the-art instruments to monitor compositions of non-refractory sub-micron particulate matter (NR-PM1) and gaseous pollutants. Results showed that the average NR-PM1 concentration was 26.1 ± 0.7 μg/m3 (average ± 95% confidence interval) and organic aerosol (OA) contributed the most to NR-PM1 with a proportion of 57.7 ± 0.2%. The aerosol size distributions of bulk composition of NR-PM1 presented a peak at ~600 nm with internal mixtures of the organic and inorganic components, while there were a larger proportion of primary organic particles at < 200 nm, indicating intensive emissions of primary organics at this site. Positive matrix factorization (PMF) analysis was applied to the measurement data and four OA components were identified, including a hydrocarbon-like OA (HOA) factor, a cooking organic aerosol (COA) factor and two oxygenated OA (OOA) factors of different oxidation levels: less oxidized OOA (LO-OOA) and more oxidized OOA (MO-OOA). Strikingly, the contribution of MO-OOA was the highest (30.9 ± 0.4%), suggesting high oxidation degree and/or high regional background in the roadside environment. Moreover, the proportion of COA reached 25.4 ± 0.3% at this roadside site with heavy traffic fleet, which was even higher than the percentage of HOA (p < 0.01). The average ratio of C3H3O+ / C3H5O+ (2.01 ± 0.01) and the opposite pattern of C3H3O+ / C3H5O+ to Ox during daytime hours suggested that the COA was oxidized to some extent when transported to the site. The findings implied that cooking activities are a significant source of organic aerosols in Hong Kong, even at a busy road. Control measures should focus on both cooking and traffic emissions in Hong Kong.
AB - A sampling campaign was conducted at an urban roadside site in Hong Kong from Nov. to Dec. in 2017 using a suite of state-of-the-art instruments to monitor compositions of non-refractory sub-micron particulate matter (NR-PM1) and gaseous pollutants. Results showed that the average NR-PM1 concentration was 26.1 ± 0.7 μg/m3 (average ± 95% confidence interval) and organic aerosol (OA) contributed the most to NR-PM1 with a proportion of 57.7 ± 0.2%. The aerosol size distributions of bulk composition of NR-PM1 presented a peak at ~600 nm with internal mixtures of the organic and inorganic components, while there were a larger proportion of primary organic particles at < 200 nm, indicating intensive emissions of primary organics at this site. Positive matrix factorization (PMF) analysis was applied to the measurement data and four OA components were identified, including a hydrocarbon-like OA (HOA) factor, a cooking organic aerosol (COA) factor and two oxygenated OA (OOA) factors of different oxidation levels: less oxidized OOA (LO-OOA) and more oxidized OOA (MO-OOA). Strikingly, the contribution of MO-OOA was the highest (30.9 ± 0.4%), suggesting high oxidation degree and/or high regional background in the roadside environment. Moreover, the proportion of COA reached 25.4 ± 0.3% at this roadside site with heavy traffic fleet, which was even higher than the percentage of HOA (p < 0.01). The average ratio of C3H3O+ / C3H5O+ (2.01 ± 0.01) and the opposite pattern of C3H3O+ / C3H5O+ to Ox during daytime hours suggested that the COA was oxidized to some extent when transported to the site. The findings implied that cooking activities are a significant source of organic aerosols in Hong Kong, even at a busy road. Control measures should focus on both cooking and traffic emissions in Hong Kong.
KW - Cooking organic aerosol
KW - Organic aerosol
KW - Oxygenated organic aerosol
KW - Positive matrix factorization
UR - http://www.scopus.com/inward/record.url?scp=85102001272&partnerID=8YFLogxK
U2 - 10.1016/j.atmosenv.2021.118298
DO - 10.1016/j.atmosenv.2021.118298
M3 - Journal article
AN - SCOPUS:85102001272
SN - 1352-2310
VL - 252
JO - Atmospheric Environment
JF - Atmospheric Environment
M1 - 118298
ER -
