Almost the entire global population (99%) breathes air that exceeds World Health Organization (WHO) air quality limits, and threatens their health. A record number of over 6,000 cities in 117 countries are now monitoring air quality, but the people living in them are still breathing unhealthy levels of fine particulate matter and nitrogen dioxide, with people in low and middle-income countries suffering the highest exposures.
The findings have prompted the WHO to highlight the importance of curbing fossil fuel use and taking other tangible steps to reduce air pollution levels.
The 2022 update of the World Health Organization’s air quality database introduces ground measurements of nitrogen dioxide (NO2) concentrations, a common urban pollutant and precursor of particulate matter and ozone. It also includes measurements of particulate matter with diameters equal or smaller than 10 μm (PM10) or 2.5 μm (PM2.5). Both groups of pollutants primarily originate from human activities related to fossil fuel combustion.
The new air quality database is the most extensive yet in its coverage of air pollution exposure on the ground. Some 2,000 more population centers are now recording ground monitoring data for particulate matter. than the last update.
Evidence that air pollution damages the human body has been growing rapidly and shows that even low levels of many air pollutants cause significant harm.
Particulate matter can penetrate deep into the lungs and enter the bloodstream, causing cardiovascular, cerebrovascular (stroke) and respiratory impacts. There is emerging evidence that particulate matter impacts other organs and causes other diseases as well.
Nitrogen dioxide is associated with respiratory diseases, particularly asthma, which leads to respiratory symptoms (such as coughing, wheezing or difficulty breathing), hospital admissions and visits to emergency rooms.
Last year, the World Health Organization revised its Air Quality Guidelines to make them more stringent in an effort to help countries better evaluate the healthiness of their own air.
“Current energy concerns highlight the importance of speeding up the transition to cleaner, healthier energy systems,” said Dr Tedros Adhanom Ghebreyesus, WHO Director-General. “High fossil fuel prices, energy security, and the urgency of addressing the twin health challenges of air pollution and climate change, underscore the pressing need to move faster towards a world that is much less dependent on fossil fuels.”
Countries with high income see lower particulate pollution, but most cities have trouble with nitrogen dioxide
“After surviving a pandemic, it is unacceptable to still have 7 million preventable deaths and countless preventable lost years of good health due to air pollution. That’s what we’re saying when we look at the mountain of air pollution data, evidence, and solutions available. Yet too many investments are still being sunk into a polluted environment rather than in clean, healthy air,” said Dr Maria Neira, WHO Director, Department of Environment, Climate Change and Health.
In the 117 countries monitoring air quality, the air in 17% of cities in high-income countries fall below the WHO’s Air Quality Guidelines for fine particulate matter. In low- and middle-income countries, air quality in less than 1% of the cities complies with WHO recommended thresholds.
Globally, low- and middle-income countries still experience greater exposure to unhealthy levels of particulate matter compared to the global average, but nitrogen dioxide patterns are different, showing less difference between the high- and low- and middle-income countries.
About 4,000 population centers in 74 countries collect nitrogen dioxide data at ground level. Aggregated, their measurements show that only 23% of people in these places breathe annual average concentrations of nitrogen dioxide that meet levels in the recently updated version of WHO’s Air Quality Guidelines.