Declining air pollution levels continue to improve life expectancy in US

December 3, 2012, Harvard School of Public Health

A new study led by researchers at Harvard School of Public Health (HSPH) has found an association between reductions in fine particulate matter and improved life expectancy in 545 counties in the U.S. from 2000 to 2007. It is the largest study to date to find beneficial effects to public health of continuing to reduce air pollution levels in the U.S.

The study appears in the December 3, 2012 online edition of the journal Epidemiology.

"Despite the fact that the U.S. population as a whole is exposed to much lower levels of than 30 years ago—because of great strides made to reduce people's exposure—it appears that further reductions in would continue to benefit public health," said lead author Andrew Correia, a PhD candidate in the Department of Biostatistics at HSPH.

The study looked at the effects on health of fine particulate matter, small particles of 2.5 micrometers or less in diameter—referred to as PM2.5. Numerous studies have shown associations between acute and chronic exposure to fine particle air pollution and cardiopulmonary disease and mortality. Studies have also shown that reductions in air pollution are associated with reductions in and improved life expectancy. Air pollution has been declining steadily in the U.S. since 1980, but the rate has slowed in the years since 2000. The HSPH researchers wanted to know whether the relatively smaller decreases in PM2.5 levels since 2000 are still improving life expectancy.

Controlling for socioeconomic status, smoking prevalence, and demographic characteristics, the results showed that a decrease of 10 micrograms per cubic meter (10 μg/m3 ) in the concentration of PM2.5 during the period 2000 to 2007 was associated with an average increase in life expectancy of 0.35 years in 545 U.S. counties.

The research expanded on a 2009 study published in the by some of the same authors (Pope, Ezzati, and Dockery) that found that reduced air pollution was associated with increased life expectancy in 211 urban counties. This new study looked at more recent data, more than two-and-a-half times as many counties, and included both rural and urban areas. The findings showed that there's a stronger association between declining air pollution and increased life expectancy in more urban, densely populated areas than in rural areas. The results also suggested that reduced levels of air pollution may be more beneficial to women than to men.

As to why there was a stronger association between reductions in and improvements in in urban areas, the researchers speculated that the composition of the particulates there may be different from that in rural areas.

"Since the 1970s, enactment of increasingly stringent air quality controls has led to improvements in ambient air quality in the United States at costs that the U.S. Environ¬mental Protection Agency has estimated as high as $25 billion per year. However, the extent to which more recent regulatory actions have benefited remains in question. This study provides strong and compelling evidence that continuing to reduce ambient levels of PM2.5 prolongs life," said senior author Francesca Dominici, professor of biostatistics at HSPH.

Explore further: Long-term exposure to air pollution increases risk of hospitalization for lung, heart disease

More information: "The Effect of Air Pollution Control on Life Expectancy in the United States: An Analysis of 545 US Counties for the Period 2000 to 2007," Andrew W. Correia, C. Arden Pope III, Douglas W. Dockery, Yun Wang, Majid Ezzati, Francesca Dominici, Epidemiology, December 3, 2012 online edition

Related Stories

Long-term exposure to air pollution increases risk of hospitalization for lung, heart disease

April 17, 2012
Older adults may be at increased risk of being hospitalized for lung and heart disease, stroke, and diabetes following long-term exposure to fine-particle air pollution, according to a new study by researchers at Harvard ...

Study finds association between air pollution and cognitive decline in women

February 13, 2012
A large, prospective study led by a researcher at Rush University Medical Center indicates that chronic exposure to particulate air pollution may accelerate cognitive decline in older adults. The results of the study will ...

Gestational exposure to urban air pollution linked to vitamin D deficiency in newborns

September 13, 2012
Gestational exposure to ambient urban air pollution, especially during late pregnancy, may contribute to lower vitamin D levels in offspring, according to a recent study accepted for publication in The Endocrine Society's ...

Recommended for you

Who uses phone apps to track sleep habits? Mostly the healthy and wealthy in US

January 16, 2018
The profile of most Americans who use popular mobile phone apps that track sleep habits is that they are relatively affluent, claim to eat well, and say they are in good health, even if some of them tend to smoke.

Improvements in mortality rates are slowed by rise in obesity in the United States

January 15, 2018
With countless medical advances and efforts to curb smoking, one might expect that life expectancy in the United States would improve. Yet according to recent studies, there's been a reduction in the rate of improvement in ...

Teens likely to crave junk food after watching TV ads

January 15, 2018
Teenagers who watch more than three hours of commercial TV a day are more likely to eat hundreds of extra junk food snacks, according to a report by Cancer Research UK.

Can muesli help against arthritis?

January 15, 2018
It is well known that healthy eating increases a general sense of wellbeing. Researchers at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have now discovered that a fibre-rich diet can have a positive influence ...

Your dishwasher is not as sterile as you think

January 13, 2018
(HealthDay)—Your dishwasher may get those plates spotless, but it is also probably teeming with bacteria and fungus, a new study suggests.

Study reveals what sleep talkers have to say

January 12, 2018
A team of researchers with members from several institutions in France has conducted a study regarding sleep talking and has found that most sleep talking is not only negative in nature, but involves a large amount of swearing. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.