It may be personal, occupational or community air pollution.
Mount St Helens erupting
Ash from volcanic eruptions is an example of primary pollutants
Air pollution is usually described as either primary pollutants or secondary pollutants. Primary pollutants are pollutants that are put directly into the air by humans or natural sources. Examples of primary pollutants are exhaust fumes (gas) from cars, soot from smoke, dust storms and ash from volcanic eruptions (as seen in the picture on the left).[1]
Secondary pollutants are pollutants that are made from chemical reactions when pollutants mix with other primary pollutants or natural substances like water vapor.[1] Many secondary pollutants are made when a primary pollutant reacts with sunlight. Ozone and smog are secondary pollutants. Ozone is a gas that stops harmful ultraviolet rays from the sun. When it is near the ground, though, it can poison people and other organisms