Air Pollution Research Center, University of California, Riverside, California 92521, United States.
Environ Sci Technol. 2012 Jul 17;46(14):7535-42. doi: 10.1021/es3009826. Epub 2012 Jul 3.
Dimethylnitronaphthalene (DMNN) formation yields from the reactions of 1,7- and 2,7- dimethylnaphthalene (DMN) with OH radicals were measured over the NO(2) concentration range 0.04-1.4 ppmv. The measured DMNN formation yields under conditions that the OH-DMN adducts reacted solely with NO(2) were 0.252 ± 0.094% for Σ1,7-DMNNs and 0.010 ± 0.005% for Σ2,7-DMNNs. 1,7-DM-5-NN was the major isomer formed, with a limiting high-NO(2) concentration yield of 0.212 ± 0.080% and with equal reactions of the adduct with NO(2) and O(2) occurring in air at 60 ± 39 ppbv of NO(2). The reactions of the OH-DMN adducts with NO(2) must therefore result in products other than DMNNs. Although the yields of the DMNNs are low, ≤0.3%, the DMNN (and ethylnitronaphthalene) profiles from chamber experiments match well with those observed in polluted urban areas under conditions where OH radical-initiated chemistry is dominant. Daytime OH radical and nighttime NO(3) radical reactions appear to account for the alkylnitronaphthalenes formed and their observed profiles under most urban atmospheric conditions, with profiles reflecting daytime OH chemistry modified by contributions from isomers formed by any NO(3) radical chemistry that had occurred. Since the formation yields and NO(2) dependencies for the formation of a number of alkylnitronaphthalenes have now been measured, the effect of NO(x) emissions control strategies on their atmospheric formation can be quantitatively assessed, and the decrease in formation of these genotoxic species may provide a previously unrecognized health benefit of NO(x) control.
1,7- 和 2,7-二甲基萘（DMN）与 OH 自由基反应生成二甲基硝萘（DMNN）的产率在 NO2 浓度范围为 0.04-1.4 ppmv 下进行了测量。在仅使 OH-DMN 加合物与 NO2 反应的条件下，Σ1,7-DMNNs 的实测 DMNN 生成产率为 0.252±0.094%，Σ2,7-DMNNs 的实测 DMNN 生成产率为 0.010±0.005%。1,7-DM-5-NN 是主要生成的异构体，在高 NO2 浓度极限下的产率为 0.212±0.080%，并且在 60±39 ppbv 的 NO2 下，空气中的加合物与 NO2 和 O2 具有相等的反应活性。因此，OH-DMN 加合物与 NO2 的反应必须导致除 DMNN 之外的产物。尽管 DMNN 的产率较低（≤0.3%），但腔室实验中的 DMNN（和乙基硝萘）分布与污染城市地区中在 OH 自由基引发的化学占主导地位的条件下观察到的分布非常吻合。白天的 OH 自由基和夜间的 NO3 自由基反应似乎可以解释在大多数城市大气条件下形成的烷基硝萘及其观察到的分布，这些分布反映了白天 OH 化学的情况，其受到任何已经发生的 NO3 自由基化学形成的异构体的贡献的影响。由于现在已经测量了一些烷基硝萘形成的产率和 NO2 依赖性，因此可以定量评估 NOx 排放控制策略对其大气形成的影响，并且这些遗传毒性物质形成的减少可能提供了以前未被认识到的 NOx 控制的健康益处。
