A new study shows that air pollution at levels below the National Ambient Air Quality Standards (NAAQS) could cut short life spans. This was one of the largest air pollution studies with more than a whopping 60 million senior citizens participating. The study was published in the Thursday’s edition of the journal New England Journal of Medicine.
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The study noted among these participants that two major air pollutants or pollutants present in smog - ozone and fine particulate matter when inhaled for a very long time could significantly increase the risk of premature death. The researchers from Harvard University find that all levels of air pollution are significant and there is no set lower limit of exposure that could minimize the risk. There was in fact no lower limit below which the risk of death was low.
Researchers explained that fine particulate matter contains tiny specks of dust that when inhaled get lodged deep inside the lungs and are connected to cardiovascular and lung diseases. Ozone is a gas that irritates the lung tissues when inhaled and is typically found in warm weather smog. It has been connected with worsening of asthma and other lung disorders for some time now. These two pollutants are usually found in inhaled air from their various sources including power plants, combustion sources and vehicle emissions.
For this study the researchers it would take a reduction of fine particle matter by 1 microgram per cubic meter nationwide that could save around 12,000 lives each year. By reducing ozone pollution by 1 part per billion, a further 1900 persons’ loves could be saved they calculated.
To arrive at these numbers, the researchers developed a complex mathematical model for the computer to calculate. The computer would measure the data regarding the air monitoring findings on the ground, measurements made by the satellite to estimate the levels of air pollution across the United States breaking it up into 1 square kilometre zones. The model then paired this information with the data on general health from the Medicare claims records between 2000 and 2012 in the 48 states. The beneficiaries noted were nearly 97% of the population over the age of 65.
From these complex calculations the scientists could estimate the health effects of air pollution and they were surprised to find that the effects of air pollution persisted even at legally safe levels. Fine particulate matter, for example has a legal limit of 12 micrograms per cubic meter of air. Seniors exposed to as low as 5 micrograms per cubic meter were also at risk. This was the lowest measure of fine particulate matter that the researchers came across. As for ozone, the safe EPA limit is 70 parts per billion. However increased risk of dying was noted among seniors exposed to levels as low as 30 parts per billion – the smallest that the researchers encountered.
The calculations revealed that when the concentration of particulate matter would rise by 10 micrograms per cubic meter, the risk of death during the study period among seniors would rise by 7.3%. Similarly rise of ozone concentration by 10 parts per billion meant 1.1% increased risk of dying among seniors. Other factors that could have meant early deaths among seniors included smoking, weight, race, ethnicity and income group etc. These were taken into account before arriving at the figures of air pollution related deaths.
Francesca Dominici, a data scientist at the Harvard T.H. Chan School of Public Health and the study’s principal investigator said that the air we are breathing now is “toxic” and stronger standards of control are warranted.
Source: “Air Pollution and Mortality in the Entire Medicare Population,” Qian Di, Yan Wang, Antonella Zanobetti, Yun Wang, Petros Koutrakis, Christine Choirat, Francesca Dominici, Joel D. Schwartz, New England Journal of Medicine, June 29, 2017, doi: 10.1056/NEJMoa1702747
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