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Evaluating the Effects of Springtime Dust Storms over Beijing and the Associated Characteristics of Sub-Micron Aerosol
Peng Xu1,2, Junke Zhang2, Dongsheng Ji2, Zirui Liu2, Guiqian Tang2, Bo Hu2, Changsheng Jiang1, Yuesi Wang2
1 Key Laboratory of Eco-environments in Three Gorges Reservoir Region, Ministry of Education, Chongqing Key Laboratory of Agricultural Resources and Environment, College of Resources and Environment, Department of Environmental Science and Engineering, Southwest University, Chongqing 400716, China
2 State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China
- NR-PM1 mass concentration in spring was lower than other seasons in previous research.
- Elemental composition and source apportionment of OA are studied in spring.
- The effects of dust storm on the NR-PM1 and OA components were evaluated.
In order to understand the characteristics, sources and processes of non-refractory submicron particles (NR-PM1), an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed to acquire observational data during the spring (April 1 to 30) in Beijing, China, in 2012. Based on PM10, PM2.5 and NR-PM1 mass concentrations observation, satellite images and the back trajectory analysis, one haze and dust storm episodes were recorded during the campaign, in addition, one clean episodes was also added to the comparison as a reference. The NR-PM1 mass concentration was 97 µg m–3 during the haze episodes, while it was approximately 12 times and 1.7 times that on the clean and dust episodes, respectively. In addition, the secondary inorganic aerosol (sulfate, nitrate and ammonium) contributed the largest fraction of NR-PM1 (69%) during the haze episodes. The dust storms originated from the northwestern caused the PM10 peaking at 826 µg m–3, with an average of 364 ± 186 µg m–3 and higher than the haze episodes (241 µg m–3). In addition, compared to the clean episodes (the NR-PM1 mass was 8 µg m–3), the dust storms caused the average NR-PM1 mass reaching 56 µg m–3, corresponding to the secondary components significantly increased, including sulfate (9.5 µg m–3), nitrate (8 µg m–3), ammonium (6 µg m–3) and OOA (6 µg m–3). The backward trajectory clustering analysis indicated the air mass from the southeast (at a frequency more than 30%) contained the higher NR-PM1 concentration (more than 80 µg m–3) corresponding to the higher sulfate, nitrate and ammonium contributions.
NR-PM1; Organic aerosols; Dust storm; Springtime; Beijing.