Particulate Matter 2.5 Micron (Fine Particles) is suspended particles in the air with diameters of 2.5 micrometers or less. Fine Particles are made up from a variety of particles. Many of the particles are the result of combustion sources such as diesel and gasoline motor vehicles, open burning, residential wood burning, and utility and commercial boilers.

Fine particles are measured at Washington Park and West 18th st. This data is recorded on a hourly and daily average.

Visit this website to view current fine particle readings and to find out more.