Ozone is a gas made of three oxygen atoms. In the upper atmosphere, it forms a
protective layer that blocks harmful UV rays from the sun. However, at ground level, it is a major
component of smog. Ground-level ozone is not a primary emission from contributors to air
pollution (e.g. cars, power plants, chemical plants, industrial boilers, etc.), but is formed
secondarily through a process of chemical reactions from their emissions (e.g. NO2, VOCs,
PM2.5) and sunlight.
Ozone can cause health effects even at low levels. Exposure to ozone can cause coughing,
sore or scratchy throats, increase difficulty breathing (including pain during deep breaths),
inflame or damage airways, and aggravate lung diseases (i.e. asthma, emphysema, and chronic
bronchitis). Long-term exposure to ozone is linked to aggravation of asthma, and is likely to be
one of many causes of asthma development. Ozone formation increases during hot and sunny
days and can lead to elevated levels of ozone.
Our AQM 65 monitors measure Ozone (O3) in parts per million (ppm).
