کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8864104 | 1620297 | 2018 | 34 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Secondary inorganic aerosols formation during haze episodes at an urban site in Beijing, China
ترجمه فارسی عنوان
شکل گیری آئروسل های غیر معدنی ثانویه در جریان حوادث در یک محل شهری در پکن، چین
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علم هواشناسی
چکیده انگلیسی
Severe PM2.5 pollution was observed frequently in Beijing. We conducted highly time-resolved measurements of inorganic ions associated with PM2.5 at an urban site in Beijing from 10 February to 19 March, 2015. The average PM2.5 mass concentrations during the six haze episodes ranged from 113.0â¯Î¼g/m3 to 182.6â¯Î¼g/m3, which were more than 8 times higher than those observed in clean periods. The secondary inorganic species (NH4+, SO42â and NO3â) in PM2.5 sharply increased during the haze episodes, indicating more extensive formation of SO42â and NO3â. The sulfur oxidation ratios (SOR) and the nitrogen oxidation ratios (NOR) in haze episodes were higher than those in clean periods, which indicated that secondary transformation in haze episodes was more significant than those in clean periods. No correlations between SOR and the oxidants (O3 and HONO) and the temperature were found, whereas a high correlation between SOR and relative humidity (RH) was found in haze episodes, which implied that sulfate was mainly produced by the aqueous-phase oxidation of SO2 rather than the gas-phase conversion of SO2 to sulfate. The conversion of SO2 to SO42â was observed to be sensitive to changes in RH. Furthermore, the SOR sharply increased at RH > 60% with the highest value of 0.88â¯at RH around 80% during complicated pollution. NO2 played an important role in the rapid sulfate formation with high RH and NH3 neutralization conditions in haze episodes in Beijing. The impact of RH was less apparent for nitrate than for sulfate. Nitrate was found to be produced mainly by photochemical and heterogeneous reactions, while heterogeneous reactions had a greater influence on NOR at nighttime. The NO3â/SO42â ratio indicated that mobile sources contributed more to the formation of PM2.5 than stationary sources. The result suggested the need for control of vehicle emissions to reduce the high levels of NOx and nitrate and the severe PM2.5 pollution in Beijing.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Atmospheric Environment - Volume 177, March 2018, Pages 275-282
Journal: Atmospheric Environment - Volume 177, March 2018, Pages 275-282
نویسندگان
Rui Zhang, Xuesong Sun, Aijun Shi, Yuhu Huang, Jing Yan, Teng Nie, Xiao Yan, Xuan Li,