Sources that emit these hydrocarbons include paint booths, gasoline storage tanks, dry cleaning plants, smoke stacks, car exhaust and home chimneys. Any time fuel is burned, or evaporated, hydrocarbons escape into the air. A chemical reaction takes place with a mixture of hydrocarbons, nitrogen oxides and sunlight. This produces ozone. Particulates Particulates include any materials, except water, that exist in a finely-divided form as a liquid or solid and are suspended in the air.
Examples are dust, aerosols, ash, smoke, fumes viruses and bacteria.
Particulate levels are especially high on dry and windy days. Particulate matter of 10 microns or less in size are monitored. The nature of particulate monitoring requires lab analysis after samples are taken. This makes reporting the data in the Pollutant Standards Index impractical. The Air Quality Control Office has monitored visibility in the urban area.