Readings exceeding the acceptable range are common during periods of heavy rainfall.
The Texas Natural Resources Conservation Commission monitors ozone concentration at two stations in north Austin. The highest value recorded during a 24-hour period from midnight to midnight is reported as the daily maximum ozone level for Austin. Ozone is a photo-oxidant formed when sunlight acts upon nitrogen oxides and hydrocarbons, which are primarily associated with vehicle emissions. Ozone in the lower atmosphere can irritate the eyes and respiratory tract. Privacy Statement 2001 City of Austin, Texas .