H2O2 and O3 in the atmosphere of Los Angeles and its vicinity: factors controlling their formation and their role as oxidants of SO2
H2O2 and O3 in the atmosphere of Los Angeles and its vicinity: factors controlling their formation and their role as oxidants of SO2
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洛杉矶及其附近大气中的 H2O2 和 O3：控制其形成的因素及其作为 SO2 氧化剂的作用
DOI：
10.1029/jd094id10p12957
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发表时间：
1989
影响因子：
--
通讯作者：
I. Kaplan
中科院分区：
文献类型：
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作者：
H. Sakugawa;I. Kaplan
洛杉矶及其周边地区研究了调节气态 H2O2 和 O3 形成的因素，这两种气体被认为是大气中 SO2 的主要氧化剂。在所有研究地点，当天空晴朗或部分多云时，气态 H2O2 和 O3 的浓度在下午早些时候最高，而当天空有雾时，H2O2 浓度明显低于晴朗或部分多云条件下的浓度。为了研究气态 H2O2 的季节变化，在 1985 年 8 月至 1988 年 9 月期间在洛杉矶西部下午早些时候（1200-1600 LT）以及加利福尼亚州南部的其他地点测量了气态 H2O2 的浓度。在洛杉矶、莫哈韦沙漠和圣贝纳迪诺山脉，观测到的气态 H2O2 浓度总范围分别为 0.03–1.35 (n = 150)、0.20–2.04 (n = 16) 和 0.43–1.72 (n = 13) ppb。洛杉矶 Westwood 的平均季节性 H2O2 浓度夏季为 1 ppb，冬季约为 0.2 ppb。对于相同的采样位置，每个 H2O2 测量周期的 O3 浓度范围为 10 至 230、48 至 95 和 120 至 160 ppb，并且季节变化不像 H2O2 那样明显。统计分析表明：(1)H2O2与太阳辐射相关性最强，O3与温度、逆温层高度、NOx浓度相关性最强； (2) 1987-1988 年温暖月份期间，H2O2 浓度与 SO2 呈负相关，雾霾事件频繁发生。根据我们的观察，我们推断，在洛杉矶空气中（1）由于缺乏足够的氧化剂，冬季 SO2 产生的硫酸的速率明显低于夏季；（2）因此，通过电力公司实现的人为源 SO2 排放量的减少并没有导致雨水中硫酸的相应减少，而雨水主要发生在冬季。
Factors regulating the formation of gaseous H2O2 and O3, which are considered to be dominant oxidants for SO2 in the atmosphere, were studied in Los Angeles and its vicinity. The concentration of gaseous H2O2, as well as O3, was highest in the early afternoon at all the sites studied when the sky was clear or partially cloudy, whereas when it was hazy and foggy, H2O2 concentrations were substantially lower than those under clear or partially cloudy conditions. To study the seasonal variation of gaseous H2O2, its concentration was measured in west Los Angeles in the early afternoon (1200–1600 LT) during August 1985 to September 1988 as well as at other southern California sites. The observed total range of gaseous H2O2 concentration was 0.03–1.35 (n = 150), 0.20–2.04 (n = 16), and 0.43–1.72 (n = 13) ppb at Los Angeles, the Mojave Desert, and the San Bernardino Mountains, respectively. The mean seasonal H2O2 concentrations at Westwood, Los Angeles, were 1 ppb in summer and approximately 0.2 ppb in winter. The O3 concentration during each H2O2 measurement period ranged from 10 to 230, 48 to 95, and 120 to 160 ppb for the same sampling locations, and seasonal variation was not as pronounced as for H2O2. Statistical analysis indicated that (1) H2O2 was most correlated with solar radiation, whereas O3 was most correlated with temperature, the height of inversion layer, and the concentration of NOx; and (2) H2O2 concentration was inversely correlated with SO2 during warm months of 1987–1988, when haze events were frequently observed. From our observations we deduce that in Los Angeles air (1) the production rate of sulfuric acid from SO2 is significantly lower in winter than summer due to lack of sufficient amounts of oxidants, and (2) thus the reduction of SO2 emission from anthropogenic sources, which has been accomplished by electric utilities, has not resulted in the equivalent reduction in sulfuric acid in rainwater, where rain events principally occur in winter.