An edifying study published in the “British Medical Journal” shows that current air pollution standards are insufficient to prevent the risk of illness and death, and must therefore be revised.
- Even when met, current air pollution standards in the United States and the European Union do not prevent the risk of death.
- People exposed to fine particulate matter (PM2.5), nitrogen dioxide and black carbon are more likely to die, even when levels are low.
Numerous studies have shown the health risks of fine particle (PM2.5) and nitrogen dioxide (NO2) pollution, particularly when the levels exceed those of the standards in force. But, although established to protect human health and the environment, air quality regulations cannot totally prevent the risk of death.
This is highlighted by a study published in the British Medical Journal (BMJ) by the Institute for Risk Assessment Sciences of the University of Utrecht, the Netherlands. According to the researchers, death rates are higher among people exposed to air pollution, even if the levels were allowed by current official standards.
A significant increase in natural deaths
To find out if there is a link between pollution below the current permitted limits and the risk of illness or death, the researchers defined as limiting levels below the current limit values set by the European Union, by the United States Agency protection standards and the World Health Organization (WHO) air quality guidelines.
They then analyzed data from eight groups of people in six European countries – Sweden, Denmark, France, the Netherlands, Germany and Austria – totaling 325,367 adults, followed over a period of around 20 years. A total of 14.5% (47,131 people) died during the study period.
Analysis of the results showed that people who were more exposed to fine particles (PM2.5), nitrogen dioxide and black carbon were more likely to die. An increase in fine particle concentration of 5 µg/m3 was associated with a 13% increase in natural deaths. A 10 µg/m3 increase in nitrogen dioxide was associated with an 8.6% increase in natural deaths.
The risk of death was even more significant for people exposed to pollution levels below the US standard of 12 µg/m3: a 5 µg/m3 increase in PM2.5 particles was associated with a 29.6% increase natural deaths. For people exposed to nitrogen dioxide levels below half the current European standard of 40 µg/m3, a 10 µg/m3 increase in nitrogen dioxide was associated with a 9.9% increase in natural deaths.
Standards to review
Although this is an observational study and therefore cannot establish a cause, the researchers believe that the results “contribute to evidence that outdoor air pollution is associated with mortality even at levels below current European and North American standards and WHO guideline values”.
“These results therefore constitute an important contribution to the debate on the revision of air quality limits, guidelines and standards, as well as to future assessments of the[étude] on the global burden of disease”they conclude.
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