Almost everyone on earth breathes air that falls short of the World Health Organization’s recommended quality standards. Across more than 6,000 cities in 117 countries, people monitor air conditions daily, yet many still inhale unhealthy levels of fine particles and nitrogen dioxide. Those in lower and middle income nations carry the greatest risk.
These findings push WHO to stress concrete steps: curb fossil fuel use and implement clear policies to cut air pollution.
The latest comprehensive update to the WHO air quality database, released in 2022, adds ground based measurements for the first time. Annual averages of nitrogen dioxide are a common urban pollutant and a precursor to fine particulate matter and ozone formation.
The update also tracks particles with diameters of 10 microns or less (PM10) and 2.5 microns or less (PM2.5). Both groups largely stem from human activities, especially burning fossil fuels.
Growing evidence shows the harm caused by air pollution to the human body can occur even at low exposure levels. PM2.5 is particularly capable of penetrating deep into the lungs and entering the bloodstream, influencing the heart, brain circulation, and respiratory systems, while also affecting other organs and causing additional diseases.
respiratory diseases
NO2 exposure is linked to respiratory issues including asthma, coughing, wheezing, shortness of breath, higher hospital admissions, and more emergency room visits.
While particulate pollution tends to be lower in wealthier nations, urban NO2 problems persist worldwide.
World health leaders note the energy crisis underscores the need to move toward cleaner, healthier energy systems. The director general of WHO highlights high fossil fuel prices, energy security concerns, and the urgency of addressing the joint health risks from air pollution and climate change as reasons to accelerate change.
WHO lists nine actions for governments to adopt cleaner air and better health outcomes:
- To review and implement air quality standards aligned with WHO guidelines.
- To monitor air quality continuously and identify pollution sources.
- To support a shift to clean energy for cooking, heating, and lighting in homes.
- To build networks for pedestrians and cyclists and provide safe, affordable public transport.
- To enforce stricter vehicle emission and efficiency standards.
- To invest in homes and efficient power generation systems.
- To improve management of industrial and municipal waste.
- To reduce burning of agricultural residues, forest fires, and charcoal production.
- To include air pollution in the training programs for health professionals.
Seven million preventable deaths
Across 117 monitoring countries, nearly one in six cities in high income regions fall below the PM guideline thresholds. In contrast, less than 1% of cities in low and middle income areas meet the recommended standards.
Low and middle income regions show higher exposure to unhealthy PM levels than the global average. NO2 patterns, however, are less dramatically different from those seen in wealthier areas.
Ground level NO2 data are gathered in roughly 4,000 cities across 74 countries. Findings indicate that only about 23% of residents breathe NO concentrations within the WHO-recommended annual average.
After enduring a global pandemic, leaders emphasize that seven million deaths and countless years of life lost from air pollution remain unacceptable. Investment in a polluted environment is still common even as calls grow for clean air, according to WHO health officials.
Europe and parts of North America continue to maintain the most comprehensive air quality data. In many poorer regions, PM2.5 measurements are not yet available, but significant progress has been made since 2018 with thousands of new monitoring sites added worldwide.
WHO continues to refine its data and guidance. For the latest data, see the WHO air quality database and related analyses cited by health authorities [WHO data citation].