Khanna Isha, Khare Mukesh, Gargava Prashant, Khan Anwar Ali
a Department of Civil Engineering , Indian Institute of Technology , New Delhi , India.
b Central Pollution Control Board , New Delhi , India.
J Air Waste Manag Assoc. 2018 May;68(5):430-437. doi: 10.1080/10962247.2018.1425772.
PM sampling was conducted at a curbside location in Delhi city for summer and winter seasons, to evaluate the effect of PM and its chemical components on the visibility impairment. The PM concentrations were observed to be higher than the National Ambient Air Quality Standards (NAAQS), indicating poor air quality. The chemical constituents of PM (the water-soluble ionic species SO, NO, Cl, and NH, and carbonaceous species: organic carbon, elemental carbon) were analyzed to study their impact on visibility impairment by reconstructing the light extinction coefficient, b. The visibility was found to be negatively correlated with PM and its components. The reconstructed b showed that organic matter was the largest contributor to b in both the seasons which may be attributed to combustion sources. In summer season, it was followed by elemental carbon and ammonium sulfate; however, in winter, major contributions were from ammonium nitrate and elemental carbon. Higher elemental carbon in both seasons may be attributed to traffic sources, while lower concentrations of nitrate during summer, may be attributed to volatility because of higher atmospheric temperatures.
The chemical constituents of PM that majorly effect the visibility impairment are organic matter and elemental carbon, both of which are products of combustion processes. Secondary formations that lead to ammonium sulfate and ammonium nitrate production also impair the visibility.
在德里市的一个路边地点进行了夏季和冬季的颗粒物（PM）采样，以评估PM及其化学成分对能见度受损的影响。观察到PM浓度高于国家环境空气质量标准（NAAQS），表明空气质量较差。对PM的化学成分（水溶性离子物种SO、NO、Cl和NH，以及含碳物种：有机碳、元素碳）进行了分析，通过重建消光系数b来研究它们对能见度受损的影响。发现能见度与PM及其成分呈负相关。重建的b表明，在两个季节中，有机物对b的贡献最大，这可能归因于燃烧源。在夏季，其次是元素碳和硫酸铵；然而，在冬季，主要贡献来自硝酸铵和元素碳。两个季节中较高的元素碳可能归因于交通源，而夏季较低的硝酸盐浓度可能归因于较高大气温度导致的挥发性。
主要影响能见度受损的PM化学成分是有机物和元素碳，两者都是燃烧过程的产物。导致硫酸铵和硝酸铵产生的二次形成也会损害能见度。
