Effects of heterogeneous processes on NO3, HONO, and HNO3 chemistry in the troposphere
Effects of heterogeneous processes on NO3, HONO, and HNO3 chemistry in the troposphere
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DOI：
10.1029/jc088ic15p10883
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发表时间：
1983-12
影响因子：
--
通讯作者：
B. Heikes;A. Thompson
中科院分区：
文献类型：
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作者：
B. Heikes;A. Thompson
大气中痕量氮氧化物（即 NO3、HONO 和 HNO3）的测量与公认的光化学理论不一致。特别是，夜间测得的 NO3 水平低于光化学平衡预期的水平，观察到的 HONO 浓度在整个夜间增加，并且 HNO3 或 NO3− 在云和羽流中快速产生。我们通过结合 H-N-O 光化学和异质清除参数化的模型，从理论上研究了湿颗粒在 NO3、HONO 和 HNO3 化学中的潜在作用。该模型包括温度、压力、光稳态数、光解速率、扩散速率和粘附系数的影响。将该模型应用于合适的 NO3 案例研究表明，如果夜间存在 NO，NO 与 NO3 的反应可能会导致低 NO3 浓度。然而，在没有 NO 的情况下，NO3 和 N2O5 的异质损失可能会导致低 NO3，前提是它们的粘附系数大于 10−3。在 HONO 的研究中，我们发现异质 H2O 反应的夜间产生不足以解释观察到的 HONO 水平。模型灵敏度计算表明，云中 HNO3 或 NO3− 的形成可以通过两种不同且互补的机制发生。 OH + NO2→ HNO3 的路线可以解释云中大量 HNO3 的形成，但仅限于白天。由 NO3 和 N2O5 吸收和液滴反应组成的非均相机制被证明是云中所有小时内 HNO3 的可行来源。
Atmospheric measurements of trace oxides of nitrogen, i.e., NO3, HONO, and HNO3, are at variance with accepted photochemical theory. In particular, measured NO3 levels at night are lower than expected from photochemical equilibrium, observed HONO concentrations increase throughout the night, and HNO3 or NO3− is produced rapidly in cloud and plume. We investigate theoretically the potential role of wet particles in the chemistry of NO3, HONO, and HNO3 through a model that incorporates H-N-O photochemistry and a heterogeneous scavenging parameterization. The model includes effects due to temperature, pressure, photostationary state number, photolysis rate, diffusion rate, and sticking coefficient. Application of the model to suitable NO3 case studies reveals that low NO3 concentrations could result from the reaction of NO with NO3 provided NO is present at night. However, in the absence of NO, low NO3 can result from heterogeneous loss of NO3 and N2O5 provided their sticking coefficients are greater than 10−3. In the study of HONO we find that a nocturnal production by heterogeneous H2O reactions is insufficient to account for observed levels of HONO. Model sensitivity calculations demonstrate that the formation of HNO3 or NO3− in cloud can occur through two distinct and complementary mechanisms. The route, OH + NO2→ HNO3, can account for considerable HNO3 formation in cloud but only during daylight hours. A heterogeneous mechanism consisting of NO3 and N2O5 absorption and reaction on droplets is shown to be a viable source of HNO3 in cloud during all hours.