Temporal variability of atmospheric particulate matter and chemical composition during a growing season at an agricultural site in northeastern China

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• 作者：Weiwei Chen¹ ; ^{chenweiwei@iga.ac.cn" class="auth_mail" title="E-mail the corresponding author} ; Daniel Tong² ; Shichun Zhang¹ ; Mo Dan³ ; Xuelei Zhang¹ ; Hongmei Zhao¹
• 关键词：PM10 ; PM2.5 ; Emission factor ; Agricultural inventory ; Tillage ; Harvest ; Burning
• 刊名：Journal of Environmental Sciences
• 出版年：2015
• 出版时间：December 2015
• 年：2015
• 卷：38
• 期：Complete
• 页码：133-141
• 全文大小：658 K

文摘

This study presents the observations of PM₁₀ and PM_2.5 concentrations at an agricultural site from April to October 2012 in Dehui city, China. Ambient air was sampled by filter-based samplers and online PM monitors. The filter samples were analyzed to determine the abundance of ionic/inorganic elements, organic carbon (OC) and elemental carbon (EC). The daily PM₁₀ concentrations varied significantly over the monitoring period, with an average of 168 ± 63 (in the range of 52–277) μg/m³ during the land preparation/planting period (26 April–15 June), 85 ± 65 (36–228) μg/m³ during the growing season (16 June–25 September), and 207 ± 88 (103–310) μg/m³ during the harvest period (26 September–31 October). PM_2.5 accounted for 44%, 56% and 66% of atmospheric PM₁₀ during these periods, respectively. The PM₁₀ diurnal variation showed a distinct peak from 16:00 to 21:00 (LST) during the growing and harvesting seasons, while a gradual increase throughout the daytime until 17:00 was observed during tilling season. Mineral dust elements (Al, Ca, Fe, and Mg) dominated the PM₁₀ chemical composition during the tilling season; OC, NO₃⁻, SO₄^2 − and NH₄⁺ during the growing season; and carbonaceous species (i.e., OC and EC) during the harvesting season. Our results indicate that the soil particles emitted by farm tillage and organic matter released from straw burning are the two most significant sources of PM₁₀ emissions contributing to the recurring high pollution events in this region. Therefore, development of agricultural PM inventories from soil tillage and straw burning is prioritized to support air quality modeling.