Heterogeneous Reaction of Peroxyacetyl Nitrate on Real-World PM2.5 Aerosols: Kinetics, Influencing Factors, and Atmospheric Implications,Environmental Science & Technology

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Heterogeneous Reaction of Peroxyacetyl Nitrate on Real-World PM2.5 Aerosols: Kinetics, Influencing Factors, and Atmospheric Implications
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2022-06-15 , DOI: 10.1021/acs.est.2c03050
Mei Sun _{1,

2} , Ying Zhou ₁ , Yifei Wang ₁ , Xueqi Qiao ₁ , Jing Wang _{2,

3} , Jianbo Zhang ₁

Affiliation

The formation and decomposition of peroxyacetyl nitrate (PAN), an important atmospheric nitrogen oxide reservoir, can impact the level and cycling of free radicals and nitrogen compounds in the atmosphere. PAN sinks are poorly understood, highlighting the importance of elucidating the heterogeneous reaction of PAN on aerosol surfaces. Here, we report for the first time the uptake behavior, kinetics, and potential mechanism of PAN uptake on real-world aerosol PM_2.5 using a flow tube system. The uptake coefficients (γ) of PAN increased non-linearly from (1.5 ± 0.7) × 10^–5 at 0% relative humidity (RH) to (9.3 ± 2.0) × 10^–5 at 80% RH. The γ decrease with increasing initial PAN concentration is consistent with the Langmuir–Hinshelwood mechanism. Organic components of aerosols may promote heterogeneous loss of PAN through redox reactions. Higher γ occurs with higher water content, lower pH, and lower ionic strength in the aqueous phase of aerosols. The present study suggests that heterogeneous reaction of PAN on ambient aerosols plays a non-negligible role in the atmospheric PAN budget and provides new insights into the role of PAN in promoting atmospheric oxidation capacity during hazy periods with cold and wet weather conditions.

中文翻译：

过氧乙酰硝酸盐对真实世界 PM2.5 气溶胶的非均相反应：动力学、影响因素和大气影响

过氧乙酰硝酸盐 (PAN) 是一种重要的大气氮氧化物库，其形成和分解会影响大气中自由基和氮化合物的水平和循环。PAN 汇知之甚少，突出了阐明 PAN 在气溶胶表面上的非均相反应的重要性。在这里，我们首次使用流管系统报告了真实世界气溶胶 PM _{2.5对 PAN 的吸收行为、动力学和潜在机制。}PAN 的吸收系数 (γ) 从0% 相对湿度 (RH) 时的 (1.5 ± 0.7) × 10 ^–5非线性增加到 (9.3 ± 2.0) × 10 ^–5在 80% 相对湿度。随着初始 PAN 浓度的增加，γ 降低与 Langmuir-Hinshelwood 机制一致。气溶胶的有机成分可能通过氧化还原反应促进 PAN 的非均相损失。较高的 γ 值随着气溶胶水相中较高的水含量、较低的 pH 值和较低的离子强度而发生。本研究表明，PAN 对环境气溶胶的非均相反应在大气 PAN 预算中发挥着不可忽视的作用，并为在寒冷和潮湿天气条件下的雾霾期间 PAN 在促进大气氧化能力中的作用提供了新的见解。

更新日期：2022-06-15

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