Cleaner The Air - More Years To Live

By Margarita Nahapetyan

A new federally funded research found that reducing air pollution can prolong a person's average life by five months. The results were based on a study of urban residents in 51 of U.S. metro areas, and more than 200 other countries, over the past twenty years.

A team or researchers from Brigham Young University in Provo, Utah, and the Harvard School of Public Health conducted a "natural experiment" to determine whether cleaner air could have any effect on health. The research focused on "PM 2.5" pollution, that measures levels of tiny particles which are no bigger than 2.5 microns across, or about one-fortieth the diameter of a human hair (these particles travel all the way deep into the lungs, and can lead to asthma and heart disease).The scientists plotted pollution data for 1979-1983 against 1978-1982 life expectancies in all the areas. Then they compared pollution data for 1999-2000 with 1997-2001 life expectancies. And, finally, they studied how changes in life expectancy were related to the changes in air pollution for both periods of time.

Many factors have been considered during the study, such as increases in income, population and education, migration, demographics and reductions in smoking prevalence. After all this, it was found that the effect of air pollution reduction still took place: for each decrease of 10 micrograms of pollutant particles per cubic meter life expectancies rose nearly by seven months. And each decrease of 21 micrograms of pollutant particles per cubic meter (in 1979-1983) to 14 micrograms per cubic meter of air (by 1999-2000) was associated with an increase of about 3 years in average life expectancy. Life expectancy for the corresponding time periods rose from 74 years to 77 years of age.

The results of a research also showed that all the cities, including the ones with more or less clean air at the beginning of the study, got a boost from cleaner air. Those that began with the very lowest levels still saw health benefits from small improvements. Residents of Buffalo and Pittsburgh made the biggest gains against pollution, and therefore increased their life spans the most. People there gained more than three extra years in spite of the fact that the life expectancy in both cities still remains a little below the average.

Comparing data from different other studies, the researchers estimated that five months of the increase was attributable strictly to improvements in air quality. "This is a large, nationwide natural experiment," said C. Arden Pope III, PhD., a professor of economics at Brigham Young University, and the study lead author. "We did an intervention - improved air quality - and the question is, 'Did we get a return?' The bottom line is yes, it looks like we did. Our efforts to clean up the air are helping."

It is considered that a long-term exposure to dirty and polluted air shortens lives and leads to cardiovascular and lung diseases. We inhale dirt almost like a gas and, therefore are more likely to develop risks of heart attack, high blood pressure and the chance of heart disease-related death. The World Health Organization estimates that 1.4 per cent of all health-related concerns and deaths are a result of air pollution. The American Heart Association and the American College of Cardiology recommend those with heart problems not to drive for at least 2-3 weeks after leaving a hospital, in order to avoid pollution. Another research found that a non-smoker who lives in a polluted area has almost the same chance of dying of heart disease as a former smoker.

In 1979, The Clean Air Act for the first time ever set nationwide air quality standards and motor-vehicle emissions standards. Since then federal government and some of the U.S states have been working hard to reduce the problem of air pollution. The next step for both scientists and government is to establish exactly which source of dirt, such as industrial polluters, motor vehicles or power plants, contribute the most to levels of particles, and therefore address them in a proper way.

"While there is plenty of research linking air pollution to increased mortality and worse health," said Daniel Krewski, Ph.D., a pollution researcher, professor of epidemiology and medicine at the University of Ottawa in Canada, "The current study is among the first to show how cleaning up pollution affects health. It's a very important contribution," added Krewski, who wrote an accompanying editorial in the medical journal.

Bert Brunekreef, Ph.D., director of the Institute for Risk Assessment Sciences at the University of Utrecht in the Netherlands, said the current research could help encourage government and many relevant organizations to address the problem of air pollution around the world where it is a serious threat to health. "Showing public health benefits of changes in pollution is a strong message, comparable to studies documenting health benefits of smoking bans," he said via email.

The study was published in the latest issue of The New England Journal of Medicine.