Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
Environ Health Perspect. 2012 Oct;120(10):1404-10. doi: 10.1289/ehp.1104851. Epub 2012 Jul 18.
Exposure to ozone has been associated with adverse health effects, including premature mortality and cardiopulmonary and respiratory morbidity. In 2008, the U.S. Environmental Protection Agency (EPA) lowered the primary (health-based) National Ambient Air Quality Standard (NAAQS) for ozone to 75 ppb, expressed as the fourth-highest daily maximum 8-hr average over a 24-hr period. Based on recent monitoring data, U.S. ozone levels still exceed this standard in numerous locations, resulting in avoidable adverse health consequences.
We sought to quantify the potential human health benefits from achieving the current primary NAAQS standard of 75 ppb and two alternative standard levels, 70 and 60 ppb, which represent the range recommended by the U.S. EPA Clean Air Scientific Advisory Committee (CASAC).
We applied health impact assessment methodology to estimate numbers of deaths and other adverse health outcomes that would have been avoided during 2005, 2006, and 2007 if the current (or lower) NAAQS ozone standards had been met. Estimated reductions in ozone concentrations were interpolated according to geographic area and year, and concentration-response functions were obtained or derived from the epidemiological literature.
We estimated that annual numbers of avoided ozone-related premature deaths would have ranged from 1,410 to 2,480 at 75 ppb to 2,450 to 4,130 at 70 ppb, and 5,210 to 7,990 at 60 ppb. Acute respiratory symptoms would have been reduced by 3 million cases and school-loss days by 1 million cases annually if the current 75-ppb standard had been attained. Substantially greater health benefits would have resulted if the CASAC-recommended range of standards (70-60 ppb) had been met.
Attaining a more stringent primary ozone standard would significantly reduce ozone-related premature mortality and morbidity.
臭氧暴露与不良健康影响有关，包括过早死亡以及心肺和呼吸道发病率。2008 年，美国环境保护署（EPA）将臭氧的主要（基于健康的）国家环境空气质量标准（NAAQS）降低至 75ppb，这是 24 小时周期内第四高的每日最大 8 小时平均值。根据最近的监测数据，美国许多地方的臭氧水平仍超过这一标准，导致了可避免的不良健康后果。
我们试图量化实现当前主要 NAAQS 标准 75ppb 以及两个替代标准水平 70 和 60ppb 的潜在人类健康益处，这两个替代标准水平代表了美国 EPA 清洁空气科学咨询委员会（CASAC）建议的范围。
我们应用健康影响评估方法来估计，如果在 2005 年、2006 年和 2007 年达到当前（或更低）NAAQS 臭氧标准，将会避免多少死亡人数和其他不良健康后果。根据地理区域和年份对估计的臭氧浓度降低进行插值，并且根据流行病学文献获得或推导浓度-反应函数。
我们估计，在 75ppb 时，每年避免与臭氧相关的过早死亡人数将从 1410 人到 2480 人不等，在 70ppb 时从 2450 人到 4130 人不等，在 60ppb 时从 5210 人到 7990 人不等。如果达到当前的 75ppb 标准，每年将减少 300 万例急性呼吸道症状和 100 万例学校缺勤。如果达到 CASAC 推荐的标准范围（70-60ppb），则会带来更大的健康益处。
实现更严格的主要臭氧标准将显著减少与臭氧相关的过早死亡和发病率。
