Hogsett William E, Tingey David T, Lee E Henry, Beedlow Peter A, Andersen Christian P
U.S. EPA, Office of Research and Development, National Environmental and Health Effects Laboratory, Western Ecology Division, Corvallis, Oregon 97333, USA.
Environ Manage. 2008 Jun;41(6):937-48. doi: 10.1007/s00267-007-9057-3.
We demonstrate an approach for evaluating the level of protection attained using a variety of forms and levels of past, current, and proposed Air Quality Standards (AQSs). The U.S. Clean Air Act requires the establishment of ambient air quality standards to protect health and public welfare. However, determination of attainment of these standards is based on ambient pollutant concentrations rather than prevention of adverse effects. To determine if a given AQS protected against adverse effects on vegetation, hourly ozone concentrations were adjusted to create exposure levels that "just attain" a given standard. These exposures were used in combination with a physiologically-based tree growth model to account for the interactions of climate and ozone. In the evaluation, we used ozone concentrations from two 6-year time periods from the San Bernardino Mountains in California. There were clear differences in the level of vegetation protection achieved with the various AQSs. Based on modeled plant growth, the most effective standards were the California 8-hr average maximum of 70 ppb and a seasonal, cumulative, concentration-weighted index (SUM06), which if attained, resulted in annual growth reductions of 1% or less. Least effective was the 1-hr maximum of 120 ppb which resulted in a 7% annual reduction. We conclude that combining climate, exposure scenarios, and a process-based plant growth simulator was a useful approach for evaluating effectiveness of current or proposed air quality standards, or evaluating the form and/or level of a standard based on preventing adverse growth effects.
我们展示了一种方法，用于评估使用各种形式和水平的过去、当前及提议的空气质量标准（AQS）所达到的保护水平。美国《清洁空气法》要求制定环境空气质量标准以保护健康和公众福利。然而，这些标准是否达标的判定是基于环境污染物浓度，而非预防不利影响。为确定给定的空气质量标准是否能防止对植被产生不利影响，对每小时的臭氧浓度进行调整，以创建“刚好达到”给定标准的暴露水平。这些暴露水平与基于生理的树木生长模型相结合，以考虑气候和臭氧的相互作用。在评估中，我们使用了加利福尼亚州圣贝纳迪诺山脉两个6年期的臭氧浓度数据。不同的空气质量标准在植被保护水平上存在明显差异。基于模拟的植物生长情况，最有效的标准是加利福尼亚州8小时平均最大值70 ppb和一个季节性、累积性、浓度加权指数（SUM06），如果达到这些标准，每年的生长减少量为1%或更低。最无效的是1小时最大值120 ppb，这导致每年生长减少7%。我们得出结论，将气候、暴露情景和基于过程的植物生长模拟器相结合，是评估当前或提议的空气质量标准有效性，或基于防止不利生长影响来评估标准的形式和/或水平的一种有用方法。
