Characteristics, sources and evolution processes of atmospheric organic aerosols at a roadside site in Hong Kong
Research output: Journal Publications and Reviews (RGC: 21, 22, 62) › 21_Publication in refereed journal › peer-review
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Detail(s)
Original language | English |
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Article number | 118298 |
Journal / Publication | Atmospheric Environment |
Volume | 252 |
Online published | 26 Feb 2021 |
Publication status | Published - 1 May 2021 |
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Abstract
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.
Research Area(s)
- Cooking organic aerosol, Organic aerosol, Oxygenated organic aerosol, Positive matrix factorization
Citation Format(s)
Characteristics, sources and evolution processes of atmospheric organic aerosols at a roadside site in Hong Kong. / Yao, Dawen; Lyu, Xiaopu; Lu, Haoxian; Zeng, Lewei; Liu, Tengyu; Chan, Chak K.; Guo, Hai.
In: Atmospheric Environment, Vol. 252, 118298, 01.05.2021.Research output: Journal Publications and Reviews (RGC: 21, 22, 62) › 21_Publication in refereed journal › peer-review