Percentage of population exposed to a fine particulate matter (PM2.5) concentration greater than 25 micrograms (μg) per cubic meter (m3).

WHO provides air quality guidelines based on scientific evidence and expert advice. 25 μg/m3 is interim target-2: In addition to other health benefits, these levels lower the risk of premature mortality by approximately 6% [2–11%] relative to the IT-1 level (35 μg/m3). Data on exposure to more than 35 μg/m3 is included in the Green Growth dataset.