Chock D P
JAPCA. 1989 Aug;39(8):1063-72. doi: 10.1080/08940630.1989.10466591.
The present National Ambient Air Quality Standard for ozone has many statistical problems, including use of extreme values which have inherent large fluctuations, a compliance test that can gradually lower the target of the design value below the standard level, and inconsistencies between the number-of-exceedances criterion and the design value. The above problems can be avoided or minimized by using a more robust statistic, such as the 95th percentile, and applying a statistical compliance test, without sacrificing the stringency of the standard. Analysis of EPA's ozone data shows that the annual 95th percentiles and their three-year means have less variability than the annual second highest values and the fourth highest values in three years, respectively. At t test for the mean of the annual 95th percentiles is proposed for compliance testing not only to preserve the averaging concept of the present standard, but also to take account of ozone concentration fluctuations in order to increase the stability of the compliance status of a site or a Metropolitan Statistical Area. A procedure is provided to adjust the level of the 95th-percentile standard so that the stringency of the present standard is preserved.
现行的国家臭氧环境空气质量标准存在诸多统计问题，包括使用具有固有大幅波动的极值、一种能将设计值目标逐渐降低至标准水平以下的达标测试，以及超标次数标准与设计值之间的不一致性。通过使用更稳健的统计量（如第95百分位数）并应用统计达标测试，上述问题能够避免或最小化，同时又不牺牲标准的严格性。对美国环境保护局（EPA）臭氧数据的分析表明，年度第95百分位数及其三年均值的变异性分别小于年度第二高值和三年中的第四高值。提出了对年度第95百分位数均值进行t检验以用于达标测试，这不仅是为了保留现行标准的平均概念，也是为了考虑臭氧浓度波动，从而提高一个监测点或一个大都市统计区达标状况的稳定性。提供了一个程序来调整第95百分位数标准的水平，以便保持现行标准的严格性。
