Particulates, also known as particulate matter, is a type of air
pollutant consisting of a complex mixture of extremely small particles
and liquid droplets. Particle pollution is made up of a number of components,
including acids (such as nitrates and sulfates), organic chemicals, metals,
and soil or dust particles.
The size of particles is directly linked to their potential for causing
health problems. The most danger is presented by particles that are 10 micrometers
in diameter or smaller because those are the particles that generally pass
through the throat and nose and enter the lungs. Once inhaled, these particles
can affect the heart and lungs and cause serious health effects. The US
Environmental Protection Agency groups particle pollution into two categories:
- Inhalable coarse particles, such as those found near
roadways and dusty industries, are larger than 2.5 micrometers and smaller
than 10 micrometers in diameter.
- Fine particles, such as those found in smoke and
haze, are 2.5 micrometers in diameter and smaller. These particles can
be directly emitted from sources such as forest fires, or they can form
when gases emitted from power plants, industries and automobiles react
in the air.
AND THE ENVIRONMENT