Air pollution pinpointed as major global health problem
By Nancy Lamontagne
Findings from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2010 underscore the conventional wisdom that air pollution is a major health risk factor across the globe. The study also shows that noncommunicable diseases, such as cancer and heart disease, are now the main causes of death and disability worldwide.
GBD 2010, a large global health project, systematically examined the global distribution and causes of major diseases, injuries, and health risk factors.
“The study showed that global particulate matter pollution is a major avoidable risk to the health of humankind,” said NIEHS grantee George Thurston, Sc.D., of New York University Langone Medical Center, and co-author on three of the seven GBD 2010 papers published December 2012 in The Lancet. “A high policy priority must be to reduce sources of particulate matter air pollution,” argued Thurston.
Air pollution, life expectancy, and quality of life
Thurston, who served on the GBD Outdoor Air Pollution Expert Group, pointed to the record high particulate matter (PM) air pollution Beijing experienced in January, along with recent studies linking increasing life expectancy in the U.S. with declining PM air pollution, as further proof of the importance of reducing air pollution around the world.
One GBD 2010 paper reported that indoor household and outdoor ambient PM air pollution have a large effect on diminished quality of life. Disability-adjusted life years (DALYs) assess disease burden, by combining the years of life lost and years lived with disability. Indoor household PM air pollution contributed to 4.5 percent DALYs, and outdoor ambient PM air pollution contributed to 3.1 percent. Together, indoor and outdoor PM contributed 7.6 percent DALYs, compared to blood pressure at 7.0 percent, tobacco smoking including second-hand smoke at 6.3 percent, and alcohol use at 5.5 percent.
NIEHS grantee Kirk Smith, Ph.D., of the University of California, Berkeley, chaired the study's Household Air Pollution Expert Group. "In terms of DALYs, household air pollution was the second most important risk factor for women and girls, globally, and the largest environmental risk factor of those examined," he said. According to the study, household air pollution from solid cooking fuels directly caused 3.5 million premature deaths in 2010, and another half a million through its contribution to outdoor air pollution. The study relied heavily on the NIEHS-funded RESPIRE study in Guatemala for the impact of household air pollution on child pneumonia, which accounted for one-third of the total impact.
Assessing rural air pollution
Thurston worked with other investigators to estimate global PM2.5, ozone exposures, and the health effects arising from pollution exposure. He points out that by including rural air pollution exposures, GBD 2010 examined roughly double the population of GBD 1990. New developments made it possible to use satellite data to create global models that assess rural exposures. The estimates for the health impacts of PM2.5 and ozone made significant use of NIEHS-supported work in which Thurston examined the roles of pollution in cardiopulmonary mortality, lung cancer mortality, and substantial life-shortening.
“A pressing high priority research need is to assess which sources of particles are the most damaging — coal burning, traffic, biomass — so we can most cost-effectively reduce this public health threat,” Thurston said. Thurston and his colleagues are now working to identify the most dangerous PM sources in an NIEHS-funded study examining the effects of air pollution on the NIH-AARP Diet and Health Study cohort, which includes more than 500,000 people.
(Nancy Lamontagne is a science writer with MDB Inc., a contractor for the NIEHS Division of Extramural Research and Training, Superfund Research Program, and Worker Education and Training Program.)