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Size-segregated particle number and mass concentrations from different emission sources in urban Beijing
- Source :
- Atmospheric Chemistry and Physics, Vol 20, Pp 12721-12740 (2020)
- Publication Year :
- 2020
- Publisher :
- Copernicus GmbH, 2020.
-
Abstract
- Although secondary particulate matter is reported to be the main contributor of PM2.5 during haze in Chinese megacities, primary particle emissions also affect particle concentrations. In order to improve estimates of the contribution of primary sources to the particle number and mass concentrations, we performed source apportionment analyses using both chemical fingerprints and particle size distributions measured at the same site in urban Beijing from April to July 2018. Both methods resolved factors related to primary emissions, including vehicular emissions and cooking emissions, which together make up 76 % and 24 % of total particle number and organic aerosol (OA) mass, respectively. Similar source types, including particles related to vehicular emissions (1.6±1.1 µg m−3; 2.4±1.8×103 cm−3 and 5.5±2.8×103 cm−3 for two traffic-related components), cooking emissions (2.6±1.9 µg m−3 and 5.5±3.3×103 cm−3) and secondary aerosols (51±41 µg m−3 and 4.2±3.0×103 cm−3), were resolved by both methods. Converted mass concentrations from particle size distributions components were comparable with those from chemical fingerprints. Size distribution source apportionment separated vehicular emissions into a component with a mode diameter of 20 nm (“traffic-ultrafine”) and a component with a mode diameter of 100 nm (“traffic-fine”). Consistent with similar day- and nighttime diesel vehicle PM2.5 emissions estimated for the Beijing area, traffic-fine particles, hydrocarbon-like OA (HOA, traffic-related factor resulting from source apportionment using chemical fingerprints) and black carbon (BC) showed similar diurnal patterns, with higher concentrations during the night and morning than during the afternoon when the boundary layer is higher. Traffic-ultrafine particles showed the highest concentrations during the rush-hour period, suggesting a prominent role of local gasoline vehicle emissions. In the absence of new particle formation, our results show that vehicular-related emissions (14 % and 30 % for ultrafine and fine particles, respectively) and cooking-activity-related emissions (32 %) dominate the particle number concentration, while secondary particulate matter (over 80 %) governs PM2.5 mass during the non-heating season in Beijing.
- Subjects :
- Atmospheric Science
SUBMICRON AEROSOLS
Haze
010504 meteorology & atmospheric sciences
Particle number
010501 environmental sciences
01 natural sciences
RESOLVED EFFECTIVE DENSITY
lcsh:Chemistry
Diesel fuel
SECONDARY ORGANIC AEROSOL
AIR-POLLUTION SOURCES
PARTICULATE MATTER
11. Sustainability
SOURCE IDENTIFICATION
Gasoline
1172 Environmental sciences
0105 earth and related environmental sciences
Particulates
SEASONAL-VARIATIONS
lcsh:QC1-999
Aerosol
SOURCE APPORTIONMENT
lcsh:QD1-999
13. Climate action
Environmental chemistry
CHEMICAL SPECIATION MONITOR
BLACK CARBON
Particle
Environmental science
Particle size
lcsh:Physics
Subjects
Details
- ISSN :
- 16807324
- Volume :
- 20
- Database :
- OpenAIRE
- Journal :
- Atmospheric Chemistry and Physics
- Accession number :
- edsair.doi.dedup.....9bcf0b279a01d03dc7ef03ed680913a9
- Full Text :
- https://doi.org/10.5194/acp-20-12721-2020