Enhanced aerosol particle growth sustained by high continental chlorine emission in India
Enhanced aerosol particle growth sustained by high continental chlorine emission in India
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DOI：
10.1038/s41561-020-00677-x
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发表时间：
2021-01-25
影响因子：
18.3
通讯作者：
Coe, Hugh
中科院分区：
文献类型：
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作者：
Gunthe, Sachin S.;Liu, Pengfei;Coe, Hugh
根据颗粒物测量和热力学模型，印度城市因雾霾形成而导致能见度下降的一半归因于废物燃烧和工业产生的气相盐酸的局部排放。印度许多城市的冬季空气质量严重恶化。颗粒物是影响数百万人的主要大气污染物。特别是颗粒物的高质量浓度降低了能见度，严重损害了经济并危及人类生命。但造成霾和雾形成的潜在化学机制和物理过程仍然知之甚少。在这里，我们展示了德里和钦奈颗粒物化学成分的测量结果。我们发现德里的氯化物持续居高不下，钦奈的氯化物偶尔出现高浓度。这些测量结果与热力学模型相结合表明，在德里存在过量氨的情况下，局部大量排放的盐酸会分解成气溶胶水。水相中的高吸水性和可溶性氯化物通过共凝结显着增强了气溶胶水的吸收，从而维持了颗粒的生长，导致霾和雾的形成。因此，我们认为局部高浓度的气相盐酸（可能是含塑料废物燃烧和工业排放的）导致约 50% 的能见度降低。我们的工作表明，识别和监管气态盐酸排放对于提高印度的能见度和人类健康至关重要。
Half of the reduced visibility due to haze formation in cities in India is attributed to local emission of gas-phase hydrochloric acid from waste-burning and industry, according to measurements of particulate matter and thermodynamic modelling.Many cities in India experience severe deterioration of air quality in winter. Particulate matter is a key atmospheric pollutant that impacts millions of people. In particular, the high mass concentration of particulate matter reduces visibility, which has severely damaged the economy and endangered human lives. But the underlying chemical mechanisms and physical processes responsible for initiating haze and fog formation remain poorly understood. Here we present the measurement results of chemical composition of particulate matter in Delhi and Chennai. We find persistently high chloride in Delhi and episodically high chloride in Chennai. These measurements, combined with thermodynamic modelling, suggest that in the presence of excess ammonia in Delhi, high local emission of hydrochloric acid partitions into aerosol water. The highly water-absorbing and soluble chloride in the aqueous phase substantially enhances aerosol water uptake through co-condensation, which sustains particle growth, leading to haze and fog formation. We therefore suggest that the high local concentration of gas-phase hydrochloric acid, possibly emitted from plastic-contained waste burning and industry, causes some 50% of the reduced visibility. Our work implies that identifying and regulating gaseous hydrochloric acid emissions could be critical to improve visibility and human health in India.