UN health agency sets higher, tougher bar for air quality

The World Health Organization says the negative health impacts of poor air quality kick in at lower levels than it previously thought and is setting a higher bar for policymakers and the public in its first update to its air quality guidelines in 15 years.

The UN health agency released its revised Air Quality Guidelines on Wednesday as climate change is a leading topic at the U.N. General Assembly in New York. Chinese President Xi Jinping announced Tuesday that China will no longer fund power plants fired by coal, which generates several of the pollutants covered by the guidelines.

Since the last update of the WHO recommendations, better monitoring and science has cleared up the global picture about the impact of six major air pollutants on human health. According to the agency, 90 per cent of the world's people already live in areas with at least one particularly harmful type of pollutant.

The revisions also highlight another and often parallel aspect to environmental concerns beyond widespread worries about global warming and the impact of burning fossil fuels.

Exposure to air pollution is estimated to cause 7 million premature deaths and affect the health of millions more people each year, and air pollution is now recognized as the single biggest environmental threat to human health, said Dr. Dorota Jarosinska, WHO Europe program manager for living and working environments.

Air pollution is now comparable to other global health risks like unhealthy diet and tobacco smoking, WHO said.

The guidelines, which are intended as a reference for policymakers, advocacy groups and academics, lower the advised concentrations of six pollutants known to have impacts on health: two types of particulate matter known as PM 2.5 and PM 10, as well as ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide.

But the guidelines could also send a message to the wider public about lifestyle and business choices whether it's driving cars and trucks, disposing of garbage, working in industrial jobs or farming.

WHO says the main human-generated sources of air pollution can vary geographically but include the energy and transportation sectors, as well as waste dump sites and home cooking and heating.

We hope the tighter standards will draw attention to just how critical clean air is for human and ecosystem health, Jessica Seddon, global lead for air quality at the World Resources Institute, said. The difficulty will come in making the WHO guidelines meaningful for the average person going about their day.

While wealthy countries in Europe, Asia and North America have made strides in improving air quality in recent years, WHO says globally more than 90% of the world population breathes air with PM 2.5 concentrations that exceed the recommended levels in its last guidelines, published in 2006.

Such particles can penetrate deep into the lungs and enter the bloodstream, resulting in both respiratory and cardiovascular impacts. Air pollution has been linked to heart disease, diabetes, cancer, and early death, and recent evidence has suggested negative effects on pregnancy, cognitive development in kids, and mental health, experts say.

The new guidelines set or revise downward recommended air pollution levels for nearly all of the six particles both on a daily and annual basis. For example, they slashed the PM 2.5 recommendation on an annual basis to 5 micrograms per cubic meter, down from 10 previously.

That is just a huge change, said Susan Anenberg, associate professor of environmental and occupational health and global health at George Washington University. This annual average for PM 2.5 in the guidelines is going to be extremely difficult to meet....There's very few people on the planet right now that have exposures that are that low.