Particle pollution is the term for a mixture of solid particles and liquid droplets found in the air. These include "inhalable coarse particles," with diameters between 2.5 micrometers and 10 micrometers, and "fine particles," 2.5 micrometers and smaller.| US EPA
Air pollution kills an estimated seven million people worldwide every year. WHO data shows that 9 out of 10 people breathe air containing high levels of pollutants. WHO is working with countries to monitor air pollution and improve air quality.| www.who.int