Insights into air pollution chemistry and sulphate formation from nitrous acid (HONO) measurements during haze events in Beijing.
Insights into air pollution chemistry and sulphate formation from nitrous acid (HONO) measurements during haze events in Beijing.
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DOI：
10.1039/d0fd00100g
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发表时间：
2020-12
影响因子：
3.4
通讯作者：
W. Bloss;L. Kramer;L. Crilley;T. Vu;R. Harrison;Zongbo Shi;James D. Lee;F. Squires;L. Whalley;Eloise J. Slater;Robert Woodward-Massey;C. Ye;D. Heard;Shengrui Tong;S. Hou;Yele Sun;Jingsha Xu;Lianfang Wei;P. Fu
中科院分区：
文献类型：
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作者：
W. Bloss;L. Kramer;L. Crilley;T. Vu;R. Harrison;Zongbo Shi;James D. Lee;F. Squires;L. Whalley;Eloise J. Slater;Robert Woodward-Massey;C. Ye;D. Heard;Shengrui Tong;S. Hou;Yele Sun;Jingsha Xu;Lianfang Wei;P. Fu
在全球许多大城市，冬季城市空气污染的特点是颗粒物浓度的间歇性快速增加，与相对湿度升高相关-所谓的雾霾事件，这已成为北京等城市的特征。霾中的大气化学结合了气相和凝相化学过程，导致硫酸盐气溶胶等次生物质的增长。在这里，我们整合了反应性气相物种（HONO，OH，NOx）和时间分辨气溶胶组成的观测，探索观测的限制，负责硫酸盐生长的机制，在发病过程中的灰霾事件。我们发现，HONO丰度占主导地位的快速气相光化学，但考虑到额外的形成可能与冷凝相氧化的S物种由水NO2导致NO2生产，因此HONO释放，提高了观察到的和计算的气相HONO水平之间的协议。这一结论是高度依赖于气溶胶的pH值，离子强度，特别是参数化所采用的S（iv）氧化动力学，其上限推导。
Wintertime urban air pollution in many global megacities is characterised by episodic rapid increase in particulate matter concentrations associated with elevated relative humidity - so-called haze episodes, which have become characteristic of cities such as Beijing. Atmospheric chemistry within haze combines gas- and condensed-phase chemical processes, leading to the growth in secondary species such as sulphate aerosols. Here, we integrate observations of reactive gas phase species (HONO, OH, NOx) and time-resolved aerosol composition, to explore observational constraints on the mechanisms responsible for sulphate growth during the onset of haze events. We show that HONO abundance is dominated by established fast gas-phase photochemistry, but the consideration of the additional formation potentially associated with condensed-phase oxidation of S species by aqueous NO2 leading to NO2- production and hence HONO release, improves agreement between observed and calculated gas-phase HONO levels. This conclusion is highly dependent upon aerosol pH, ionic strength and particularly the parameterisation employed for S(iv) oxidation kinetics, for which an upper limit is derived.