💨Fine Particulate Matter Exposure (PM2.5)

How the Raw Value Is Calculated

The raw value is the annual mean population-weighted PM2.5 exposure in micrograms per cubic metre of air. PM2.5 means fine particulate matter with a diameter of 2.5 micrometres or smaller. Lower values are better.

The primary source is World Bank indicator EN.ATM.PM25.MC.M3 for population-weighted annual PM2.5 exposure. It is better suited to country comparisons than city-only data because it represents average population exposure across the country.

For countries and territories without a directly usable World Bank value, Nomadino uses maintained fallback values checked against the WHO Ambient Air Quality Database, IQAir World Air Quality Reports, regional peers and existing historical Nomadino values.

The score is inverted from the raw value: 5 µg/m³ or lower receives 100 points, 50 µg/m³ or higher receives 0 points. Between those thresholds the score declines linearly. The scale is anchored to the WHO clean-air guideline and penalises heavily polluted air clearly.

This indicator measures long-term fine-particulate exposure only. Nitrogen dioxide, ozone, short-term smog episodes, indoor air, wildfire episodes and local differences between cities and rural areas are not fully captured.