Status: this preprint was under review for the journal ACP but the revision was not accepted.
Measurement Report: Size distributions of inorganic and organic components in particulate matter from a megacity in northern China: dependence upon seasons and pollution levels
Yingze Tian1,Yinchang Feng1,Yongli Liang1,Yixuan Li1,Qianqian Xue1,Zongbo Shi2,Jingsha Xu2,and Roy M. Harrison2,aYingze Tian et al.Yingze Tian1,Yinchang Feng1,Yongli Liang1,Yixuan Li1,Qianqian Xue1,Zongbo Shi2,Jingsha Xu2,and Roy M. Harrison2,a
1State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China
2School of Geography Earth and Environmental Science, University of Birmingham, Birmingham, B152TT, UK
aalso at: Department of Environmental Sciences/Center of Excellence in Environmental Studies, King Abdulaziz University, PO Box 80203, Jeddah, 21589, Saudi Arabia
1State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention and Control, College of Environmental Science and Engineering, Nankai University, Tianjin, 300071, China
2School of Geography Earth and Environmental Science, University of Birmingham, Birmingham, B152TT, UK
aalso at: Department of Environmental Sciences/Center of Excellence in Environmental Studies, King Abdulaziz University, PO Box 80203, Jeddah, 21589, Saudi Arabia
Received: 26 May 2020 – Discussion started: 10 Aug 2020
Abstract. Size distributions of inorganic and organic components in particulate matter (PM) provide critical information on its sources, fate and pollution processes. Here, ions, elements, carbon fractions, n-alkanes, polycyclic aromatic hydrocarbons (PAHs), hopanes and steranes in size-resolved (9 stages) PM were analyzed during one year in a typical northern Chinese industrial megacity (Tianjin). We found that the concentrations of organic carbon fraction OC3, NO3− (or SO42−) and the sum of crustal elements were the highest in the pseudo-ultrafine (< 0.43 μm), fine (0.41–2.1 μm) and coarse (> 2.1 μm) modes, respectively. The diagnostic ratios of organic components consistently suggest that the traffic influence was stronger during summer and coal combustion during winter. Nitrate and high molecular weight PAHs were concentrated in the fine mode during winter, while nitrate and low molecular weight PAHs showed bimodal distributions especially during summer due to repartitioning. Long-chain n-alkanes showed a peak in the coarse mode during spring and summer, indicating a relatively stronger vegetation source and resuspended dust. Furthermore, we found a major difference in the size distribution of aerosol components during heavy pollution episodes (PM10 > 233 μg m−3) in different seasons: in spring, OC fractions, 4- and 5-ring PAHs, hopanes and C18–C33 n-alkanes were enhanced at 1.1–3.3 μm, implying that they may arise from local combustion sources which emit relatively large particles; in summer PM mass, SO42−, NH4+, Al, and C26–C33 n-alkanes were enhanced mainly in the coarse mode, peaking at 5.8–9.0 μm, indicating a large contribution from resuspended dust or heterogeneous reactions on dusts; in the winter and autumn, NO3− was significantly enhanced followed by SO42−, NH4+, OC and EC with their peaks shifting from 0.43–0.65 μm to 0.65–2.1 μm, indicating strong atmospheric processing. These results reveal that the size distributions of inorganic and organic aerosol components are dependent on the seasons and pollution levels as a result of the differing sources and physicochemical processes.
Size distributions of inorganic and organic components in particulate matter (PM) can provide critical information on sources and pollution processes. Ions, elements, carbon fractions, n-alkanes, PAHs, hopanes and steranes in size-resolved PM were analyzed during one year in a northern Chinese megacity. Results reveal that size distributions of inorganic and organic aerosol components are dependent on seasons and pollution levels as a result of differing sources and physicochemical processes.
Size distributions of inorganic and organic components in particulate matter (PM) can provide...