Thursday, July 25, 2019

Even air pollution levels which meet the air quality standards are hazardous to health

Dr KK Aggarwal

Air pollution has emerged as a major environmental risk factor for health. The hazards of air pollution that exceeds the standards are known to all and range from increased hospital admissions and emergency room visits, to increased risk of premature death. High levels of air pollution have been recognized as a cause of sudden death. Exposure to particulate matter (PM0.1, PM2.5 and PM10) is a risk factor for all-cause, cardiovascular, stroke, respiratory and chronic obstructive pulmonary disease (COPD) mortality.

Now, a study published in the journal PLoS Medicine has found that even fine particulate matter pollution levels, which mostly meet the national ambient air quality standards, are associated with mortality and loss of life expectancy due to cardiorespiratory causes.

Even though reductions in PM2.5 since 1999 have lowered mortality in the great majority of counties, PM2.5 pollution in excess of the lowest observed concentration (2.8 μg/m3) was responsible for an estimated 15,612 deaths in females and for 14,757 deaths in males.

These deaths would lower national life expectancy by an estimated 0.15 years for women and 0.13 years for men.

The life expectancy loss due to PM2.5 was largest around Los Angeles and in some southern states, such as Arkansas, Oklahoma and Alabama. At any PM2.5 concentration, life expectancy loss was, on average, larger in counties with lower income than in wealthier counties.  

The authors recommend that further lowering PM2.5 pollution is likely to benefit the health of the population and lower the health inequalities.

As per WHO, ambient or outdoor air pollution caused an estimated 4.2 million premature deaths every year mainly from heart disease, stroke, chronic obstructive pulmonary disease, lung cancer, and acute respiratory infections in children. And, 3.8 million deaths occur every year as a result of household exposure to smoke from dirty cookstoves and fuels. 91% of the world’s population lives in places where air quality exceeds WHO guideline limits.

In 2016, WHO estimated that 58% of outdoor air pollution-related premature deaths were due to ischemic heart disease and strokes, while 18% of deaths were due to COPD and acute lower respiratory infections respectively, and 6% of deaths were due to lung cancer.

As per international recommendations, levels of PM 10 and PM2.5 should be less than 40. For India, the PM10 levels should be less than 100 and PM 2.5 levels should be less than 60.

 (Source: PLoS News Release, July 23, 2019)

Dr KK Aggarwal
Padma Shri Awardee
President Elect Confederation of Medical Associations in Asia and Oceania   (CMAAO)
Group Editor-in-Chief IJCP Publications
President Heart Care Foundation of India
Past National President IMA

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