Explicit diagnosis of the local ozone production rate and the ozone-NOx-VOC sensitivities

• 来源期刊: 科学通报（英文版）
• 年，卷（期）: 2018,（16）
• 页码范围: 1067-1076
• 页数: 10页
• 语种: 英文

摘要

In the troposphere,ozone is a harmful gas compound to both human health and vegetation.Ozone is produced from the reaction of NOx (=NO + NO2) and VOCs (volatile organic compounds) with light.Due to the highly nonlinear relationships between ozone and its precursors,proper ozone mitigation relies on the knowledge of chemical mechanisms.In this study,an observation-based method is used to simulate ozone formation and elucidate its controlling factors for a rural site on the North China Plain.The instantaneous ozone production rate is calculated utilizing a box model using the dataset obtained from the Wangdu campaign.First,the model was operated in a time-dependent mode to calculate the ozone production rate at each time stamp.The calculated ozone formation rate showed a diurnal average maximum value of 17 ppbv/h (1-h diurnal averaged).The contribution of individual peroxy radicals to ozone production was analyzed.In addition,the functional dependence of calculated P(O3) reveals that ozone production was in a NOx-limited regime during the campaign.Furthermore,the missing peroxy radical source will further extend NOx-limited conditions to earlier in the day,making NOx limitation dominate more of a day than the current chemical model predicts.Finally,a multiple scenarios mode,also known as EKMA (empirical kinetic modeling approach),was used to simulate the response of P (O3) to the imaginary change in precursor concentrations.We found that ozone production was in the NOx-limited region.However,the use of NO2 measured by the molybdenum converter and/or the absence ofa peroxy radical source in the current chemical model could over-emphasize the VOC-limited effect on ozone production.