WHO announces stricter guidelines for air pollutants

September 22, 2021

The World Health Organization released new air pollution guidelines, saying the pollutants inflict damage on human health at lower concentrations than previously understood.

The WHO’s Global Air Quality Guidelines recommends nations reduce the maximum level of particulate matter, ozone, nitrogen dioxide and carbon monoxide allowed into the air, its first air quality guidelines since 2005.

The agency cut in half the recommended annual limit for fine particulate matter, PM2.5, from 10 micrograms per cubic meter to 5, and larger PM10 particulate matter from 20 micrograms per cubic meter to 15.

Under the new guidelines, the WHO would consider the U.S. Environmental Protection Agency’s current annual National Ambient Air Quality Standards for particulate matter as unsafe for human health.

The WHO also reduced the recommended annual limit of nitrogen oxides from 40 micrograms per cubic meter to 10, and established peak limit guidelines for ozone and 24-hour limits for carbon monoxide.

Surprisingly, the WHO guidelines recommendation also includes higher values for sulfur dioxide, which the agency said is due to new methodology.

“Every single year, exposure to both ambient and indoor air pollution is estimated to cause more than 7 million deaths globally, and millions more of healthy years of life lost. This burden of disease is large and it is growing and makes air pollution the single most important environmental risk factor for our health,” said WHO Regional Director for Europe Dr. Hans Henri P. Kluge during the announcement of the guidelines.

“The last time WHO published air quality guidelines was in 2006. In the 15 years since, there has been a substantial increase in evidence of how, and to what degree, air pollution affects different aspects of human health. For that reason, and after a thorough systematic review of this accumulated evidence, almost all the updated guidelines levels are now lower than they were 15 years ago.”

The WHO said the guidelines are not legally binding, but serve as a tool for policymakers to guide legislation and policies.

WHO announces stricter guidelines for air pollutants