Only 23 percent of people across 4,000 measured cities breathe nitrogen dioxide at levels inside the World Health Organization’s safety guidelines. That figure comes from the WHO’s 2022 air quality database, and it sits beside a bigger one: 99 percent of the world’s population breathes air that exceeds WHO limits. In the WHO’s own account, the cause is mostly the burning of fossil fuels.
The update, released around World Health Day, draws on more than 6000 cities in 117 countries. That is a record. About 2,000 more cities and settlements are now reporting ground data on particulate matter than in the last update, an almost 6-fold rise since the database launched in 2011. The percentage covers 80 percent of the world’s urban areas, according to ScienceAlert’s reading of the data.
Two pollutants, in plain terms
This edition adds ground measurements of nitrogen dioxide (NO2) for the first time. Cars, construction equipment, industrial boilers and power plants all put it into the air. Once inhaled, it irritates airway tissue, triggers allergies and asthma, and cuts lung function. It also raises the risk of childhood asthma, and has been linked to lower birth weight and heart disease even after short exposure.
The other group is particulate matter, tracked as PM10 and PM2.5, the numbers referring to particle width in micrometres. Think of PM2.5 as dust fine enough to slip past the lungs’ defenses. The WHO says it can reach deep into the lungs and the bloodstream, causing heart, stroke and breathing problems, and there is emerging evidence that it harms other organs too. Sources run from desert dust and wildfires to cooking fires, farming and industry.
“Air pollution has an impact at a much lower level than previously thought,” said WHO technical officer Sophie Gumy, pointing to the agency’s tightened guidelines.
Who breathes the worst
Low and middle-income countries face the highest exposures. The highest recorded PM10 was in India and the highest PM2.5 in China. For NO2 the gap between rich and poor nations is less clear, and the highest concentrations turned up around the Mediterranean.
A separate report from the Swiss company IQAir, published a month earlier, found that no country met the WHO’s PM2.5 guideline in 2021. “It is a shocking fact that no major city or country is providing safe and healthy air to their citizens,” said IQAir CEO Frank Hammes. Los Angeles was the worst US city, and wildfires pushed American PM2.5 levels up from 2020.
The fix
The WHO estimates outdoor pollution caused around 4.2 million premature deaths in 2016 from PM2.5 alone, and more than 13 million deaths a year are due to avoidable environmental causes. The agency urges deep cuts in fossil fuel use. Its Director-General, Dr Tedros Adhanom Ghebreyesus, said: “We need transformative solutions to wean the world off its addiction to fossil fuels.” The practical upshot is a familiar list: electric vehicles, public transport, renewable energy and cleaner farming.
The World Meteorological Organization backs the global commitment to cut air pollution deaths by two thirds by 2030.
Sources
- World Health Day calls for action on Our Planet, Our Health
- A Shocking 99% of Us Are Now Breathing Unhealthy Air, WHO Warns
Sources
- Billions of people still breathe unhealthy air: new WHO data
- World Health Day calls for action on Our Planet, Our Health
