WHO calls for action on global air pollution

The World Health Organisation is calling for drastic action to curb air pollution, which the group says is responsible for the deaths of an estimated 7 million people worldwide each year.

WHO data show that nine out of 10 people breathe air that contains levels of pollutants that exceed the organisation's guidelines, with low- and middle-income countries suffering from the highest exposures.

From smog hanging over cities to smoke inside the home, air pollution poses a major threat to health and climate.

The group says the combined effects of outdoor and household air pollution cause about 7 million premature deaths every year, largely as a result of increased mortality from stroke, heart disease, chronic obstructive pulmonary disease, lung cancer and acute respiratory infections.

The guidelines — the first major overhaul of the recommendations in 16 years — call for much lower daily and annual levels of exposure to six pollutants from power generation, vehicles and other sources.

The new WHO guidelines recommend air quality levels for six pollutants where evidence has advanced the most on health effects from exposure.

The stricter ceilings are due to an increase in research on the health impacts from even low levels of pollution.

“We have even stronger evidence than before on the effect of air pollution on health. Before our evidence was huge, now it’s even stronger,” says Maria Neira, director of the WHO's public health, environment and social determinants of health department.

Stephen Holgate at the University of Southampton, UK, told the New Scientist publication that population-based studies have shown “there are no safe levels of air pollution”.

The WHO concedes its air quality guidance is not legally binding but describes it as “an evidence-informed tool” for policymakers to guide legislation and regulations.

Clean air campaigners have increasingly been calling for stricter measures.

Under the new guidance, annual limits on people’s exposure to tiny particulate matter known as PM2.5, which mostly comes from burning fossil fuels in industry and vehicles, would be halved.

The WHO calculates that if the world met the new PM2.5 limits, ignoring other measures, it would cut deaths due to particulates by about 80%, or 3.3 million people a year.

“How can you refuse to reduce by 80%?” asks Neira.

IQAir’s 2020 World Air Quality Report, released earlier this year, found that while 84% of all monitored countries showed air quality improvements from 2019, largely due to global measures to slow the spread of Covid-19, only 24 out of 106 monitored countries met WHO annual guidelines for PM2.5 in 2020.

“Climate change continues to affect air quality,” IQAir says.

“The year 2020 is tied with 2016 as the hottest year on record. Wildfires and sandstorms fuelled by the warming climate led to extremely high pollution levels in California, South America, Siberia and Australia.”

In 2020, 86% of the cities in China experienced cleaner air than the previous year.

Despite this, Chinese residents are still exposed to PM2.5 levels more than three times the WHO annual guidelines.

Hotan, in north-western China, ranks as the world’s most polluted city, largely due to sandstorms exacerbated by climate change, according to IQAir.

While many cities recorded temporary improvements in air quality due to lockdowns, the health impact of burning fossil fuels remained severe in 2020 and New Delhi continued to be the world's most polluted capital city.

“To see real, long-term improvements in air quality, governments must prioritise clean energy sources such as wind and solar and promote low cost, carbon neutral and accessible transport,” says Avinash Chanchal, Climate Campaigner, Greenpeace India.

"Speeding up the transition to clean energy and clean transport not only saves lives, but also dramatically reduces healthcare-related costs."

Because of the difficulty of achieving such large air pollution cuts, the WHO also published easier interim targets while acknowledging that “key institutional and technical tools supported by human capacity-building” would be necessary to achieve that goal.

"Many parts of the world experienced unprecedented, but short-lived, improvements in air quality in 2020, as restrictions related to the Covid-19 pandemic caused a steep drop in fossil fuel consumption," says Lauri Myllyvirta, lead analyst at the Centre for Research on Energy & Clean Air (CREA), who also contributed to IQAir’s report.

"This improved air quality meant tens of thousands of avoided deaths from air pollution. By transitioning to clean energy and clean transport we can realise the same improvements in a sustained way."