Suppression of surface ozone by an aerosol-inhibited photochemical ozone regime
Suppression of surface ozone by an aerosol-inhibited photochemical ozone regime
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DOI：
10.1038/s41561-022-00972-9
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发表时间：
2022-07-01
影响因子：
18.3
通讯作者：
Lewis, Alastair C.
中科院分区：
文献类型：
--
作者：
Ivatt, Peter D.;Evans, Mathew J.;Lewis, Alastair C.
全球化学传输模拟揭示了臭氧光化学机制，其中气溶胶颗粒上氢过氧自由基的吸收主导了臭氧的产生。大气臭氧 (O-3) 是通过化学链式反应产生的污染物，其中挥发性有机化合物 (VOC)、一氧化碳和甲烷在氮氧化物 (NOx) 存在下被氧化。几十年来，控制链终止步骤一直用于将区域分为“NOx 限制”（过氧自由基自反应占主导）或“VOC 限制”（羟基自由基 (OH) + 二氧化氮 (NO2) 反应占主导）。然后，控制制度将指导减少排放和 O-3 浓度的政策。使用化学传输模型，我们表明存在第三种“气溶胶抑制”状态，其中氢过氧自由基（HO2）在气溶胶颗粒上的反应性吸收占主导地位。 1970 年，2% 的北半球人口生活在气溶胶抑制环境中，但到 2014 年，这一比例已增加至 21%；比生活在 VOC 限制条件下的人多 60%。 20 世纪 70 年代，气溶胶抑制化学物质抑制了北美和欧洲的表面 O-3 浓度，目前正在抑制亚洲上空的表面 O-3 浓度。如果不同时减少 O-3 前体排放，第三种光化学 O-3 制度会导致减少亚洲颗粒污染（当前的一项关键卫生政策和优先事项）与增加表面 O-3 之间潜在的权衡紧张。
Global chemical transport simulations reveal an ozone photochemistry regime where the uptake of hydroperoxyl radicals onto aerosol particles dominates ozone production.Atmospheric ozone (O-3) is a pollutant produced through chemical chain reactions where volatile organic compounds (VOCs), carbon monoxide and methane are oxidized in the presence of oxides of nitrogen (NOx). For decades, the controlling chain termination step has been used to separate regions into either 'NOx limited' (peroxyl-radical self-reactions dominate) or 'VOC limited' (hydroxyl radical (OH) + nitrogen dioxide (NO2) reaction dominates). The controlling regime would then guide policies for reducing emissions and so O-3 concentrations. Using a chemical transport model, we show that a third 'aerosol inhibited' regime exists, where reactive uptake of hydroperoxyl radicals (HO2) onto aerosol particles dominates. In 1970, 2% of the Northern Hemisphere population lived in an aerosol-inhibited regime, but by 2014 this had increased to 21%; 60% more than lived in a VOC-limited regime. Aerosol-inhibited chemistry suppressed surface O-3 concentrations in North America and Europe in the 1970s and is currently suppressing surface O-3 over Asia. This third photochemical O-3 regime leads to potential trade-off tensions between reducing particle pollution in Asia (a key current health policy and priority) and increasing surface O-3, should O-3 precursors emissions not be reduced in tandem.