Issue link: https://www.e-digitaleditions.com/i/1463386
40 April 2022 Inhalation ated with long-term exposures to the pollutants. Associations between mortality and exposure to low concentrations of PM 2.5 e researchers reported increased risks of all-cause mortality of 6% to 8% per 10 µg/m 3 increase in PM 2.5 across the five approaches, with larger effect estimates in a low exposure subcohort. Stronger asso- ciations were found at exposure lev- els below the current US National Ambient Air Quality Standard (NAAQS) annual average exposure of 12 µg/m 3 . e researchers also concluded that the consistency of associations across methods pro- vides stronger support than past studies for what is likely a causal effect between long-term exposure to PM 2.5 and mortality. In addition, they estimated the total number of deaths that could have been avoided among older Americans in a decade, if hypo- thetically, the US standards had followed the World Health Orga- nization annual guideline [in effect at that time] of ≤ 10 µg/m 3 and all zip codes in the US had com- plied. Using the most conservative hazard ratio across all statistical approaches, they determined that lowering the standards to 10 µg/m 3 would have saved 143,257 lives ber of the research team but inde- pendently reviewed the study. She called the report "an amazing first step" and added that "overall, the study was the most comprehensive she had seen." Coinciding with EPA review of the US PM 2.5 standard HEI and e New York Times noted the study results have become available as the Biden Administra- tion and the US EPA are consider- ing whether to strengthen the US EPA National Ambient Air Qual- ity Standards for PM 2.5 . Currently, it establishes the 24-hour average exposure limit at 35 µg/m 3 and the annual average exposure limit at 12 µg/m 3 . In con- trast, the World Health Organiza- tion air quality guidelines, which were updated in September 2021 for the first time in 15 years, have a 24-hour average exposure limit of 15 µg/m 3 while the annual expo- sure limit is 5 µg/m 3 . e US NAAQS were established in 1997 then revised in 2006 and 2012. The United States Clean Air Act requires the EPA to review the standards every five years. In a December 2020 final action fol- lowing the most recent review, the Trump Administration chose not to strengthen the guidelines. However, in June 2021, the EPA announced that it would "recon- sider the previous administration's decision to retain the particulate matter (PM) National Ambient Air Quality Standards (NAAQS)… because available scientific evidence and technical information indicate that the current standards may not be adequate to protect public health and welfare, as required by the Clean Air Act." ey further stated their "2020 Policy Assess- ment concluded that the scientific evidence and information support revising the level of the annual standard for the PM NAAQS to below the current level of 12 micrograms per cubic meter while retaining the 24-hour standard." (95% CI 115,581 to 171,645) in one decade. "If we were to reduce PM 2.5 , we would be saving a substantial amount of lives. It's highly sig- nificant," said lead investigator Francesca Dominici in the article published by e New York Times The study report was inde- pendently reviewed by the HEI Low-Exposure Epidemiology Studies Review Panel, which had no role in conducting or overseeing the study. In part, they concluded that it presented a "high-quality and thorough investigation into associations between risk of mor- tality and exposures to ambient air pollution in the United States, applying advanced statistical tech- niques to test rigorously whether the air pollution exposure actually cause[d] direct impacts on health." At the same time, the panel expressed several "concerns about some of the approaches used, such as the quality of the exposure esti- mates in rural areas." "Studying areas that are not well monitored presented a challenge because it could be difficult to val- idate levels of exposure to pollu- tion," Jennifer L. Peel, PhD, MPH, Professor and Section Head of Epi- demiology in the Department of Environmental and Radiological Health Sciences at Colorado State University, commented to e New York Times. Peel was not a mem- The Health Effects Institute (HEI) is a nonprofit corporation and an independent research or g a n i z a t i on . E s t a bl i s he d in 1980, it aims to provide "high-quality, impartial and rel- evant science on the effects of air pollution on health. Its research is selected, overseen and peer reviewed by leading subject mat- ter experts on environment and health without involvement of HEI's public or private sponsors. Typically, it receives balanced funding from the US Environ- mental Protection Agency (EPA) and the worldwide motor vehi- cle industry. In addition, other public and private organizations in the United States and around the world support its major proj- ects or research programs. HEI has funded more than 340 research projects in North America, Europe, Asia and Latin America, the results of which have informed decisions regard- ing carbon monoxide, air toxics, nitrogen oxides, diesel exhaust, ozone, particulate matter and other pollutants."