Harm introduction for fine pariticulate matters

Although the fine particles are only a few of the components of the earth's atmosphere,
it has important influence on air quality and visibility.
Compared with the coarse atmospheric particles, the particle size is small,
which is rich in toxic and harmful substances, and has long residence time in the atmosphere.
Laser particle counter can tell us how much particulates in the air.
Use the particle counter can know both PM2.5 and PM10.