Air Quality

PM2.5 — fine particulate matter smaller than 2.5 micrometres — is the air pollutant most consistently linked to serious health effects. It penetrates deep into the lungs and enters the bloodstream, contributing to heart disease, stroke, lung cancer, and respiratory illness. The WHO estimates it causes around 7 million premature deaths per year, making it the world's largest environmental health risk.

The WHO annual guideline is 5 µg/m³ (tightened from 10 µg/m³ in 2021). The vast majority of the world's population lives in areas that exceed this threshold — most of South Asia and Sub-Saharan Africa by a factor of 10 or more.

The default selection shows the full range: Bangladesh, India, and Pakistan consistently rank among the world's most polluted; China has made significant improvements since 2015 following strict enforcement of its Air Pollution Action Plan; Germany and the USA show the lower exposure levels typical of wealthy nations with strong clean air regulation.

Mean annual PM2.5 exposure over time

Values above 5 µg/m³ exceed the WHO annual guideline. The divergence between high-income and lower-income countries has widened since 1990 — improvements in Europe and North America contrast sharply with rising exposure across South Asia driven by urbanisation, traffic, and industrial growth.

All countries — most recent year

Countries ranked by current exposure. Run /owid-check if this table shows an error — the PM2.5 column name changes between OWID dataset versions.

Source: Global Burden of Disease Study (IHME) via Our World in Data. PM2.5 estimates are modelled — methodology and coverage vary by country and year.

Column note: If this page shows a query error, the OWID PM2.5 column name has changed. Run /owid-check pm25 to detect and fix the mismatch automatically.