PM2.5 air pollution, mean annual exposure (micrograms per cubic meter)

Definition

Population-weighted exposure to ambient PM2.5 pollution is defined as the average level of exposure of a nation's population to concentrations of suspended particles measuring less than 2.5 microns in aerodynamic diameter, which are capable of penetrating deep into the respiratory tract and causing severe health damage. Exposure is calculated by weighting mean annual concentrations of PM2.5 by population in both urban and rural areas.

Methodology for Environment indicators

Environmental indicators cover emissions, land use, biodiversity, and natural resources. Emissions data is often produced by international scientific consortia (EDGAR, Global Carbon Project) and typically lags 2–3 years due to the complexity of fuel- and process-level accounting. Per-capita metrics reveal a different story than absolute totals — small wealthy countries can have high per-capita emissions while contributing little to the global total.

How to interpret

• Always check the unit and reporting year before comparing values across countries.
• NULL or "Not available" means the World Bank did not publish a value — we never estimate.
• Year-over-year changes can be driven by methodology updates, not just real economic shifts.