Ozone monitoring

Ozone found in ambient air can have a direct affect on human health and also has the potential to create photochemical smog. It is for this reason that the U.S. EPA has set a one hour limit of 120 ppb and an 8 hour limit of 80 ppb. Ozone has been found to affect human health by harming the respiratory and immune system. People with pre-existing respiratory damage or diseases are more likely to suffer from the affects of ozone.

Ozone in the atmosphere is created due to photolysis of NO2 in the presence of sunlight and hydrocarbons. The NO2 is created either directly from combustion processes that include motor vehicles, power stations and other combustion sources.

Due to the low hourly average of 80 ppb, high performance analyzers with excellent detection limits are required.

The graph below illustrates the conversion of NO2 to O3 in Alpington (6 km from Melbourne CBD), notice reduction in NO2 and increase in O3 as the day progresses.