Health benefits from large-scale ozone reduction in the United States.
BACKGROUND
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.


OBJECTIVE
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).


METHODS
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.


RESULTS
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.


CONCLUSIONS
Attaining a more stringent primary ozone standard would significantly reduce ozone-related premature mortality and morbidity.
Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA.
Jesse D
JD
Berman
Neal
N
Fann
John W
JW
Hollingsworth
Kent E
KE
Pinkerton
William N
WN
Rom
Anthony M
AM
Szema
Patrick N
PN
Breysse
Ronald H
RH
White
Frank C
FC
Curriero
D000393:Air Pollutants / Q000032:analysis / Q000592:standards / Q000633:toxicity*; D000397:Air Pollution / Q000009:adverse effects / Q000032:analysis / Q000517:prevention & control*; D002318:Cardiovascular Diseases / Q000139:chemically induced / Q000453:epidemiology / Q000401:mortality*; D003198:Computer Simulation; D004781:Environmental Exposure; D062489:Health Impact Assessment; D006801:Humans; D008962:Models, Theoretical; D009017:Morbidity; D010126:Ozone / Q000032:analysis / Q000592:standards / Q000633:toxicity*; D012140:Respiratory Tract Diseases / Q000139:chemically induced / Q000453:epidemiology / Q000401:mortality*; D014481:United States / Q000453:epidemiology; D014484:United States Environmental Protection Agency
D000393:Air Pollutants; D010126:Ozone