Tropospheric Ozone

Stratospheric ozone

Occurs naturally

Reduces exposure to harmful UV light

Tropospheric ozone

A pollutant. Produced as a result of human activities. Toxic to living organisms.

Effects of Ozone

- Toxic to plants

- Reduces growth rates of trees and agricultural crops

- Causes breathing difficulties & increases asthma rates

- Involved in the production of secondary pollutants in photochemical smogs and acid rain

Sources

Photochemical reactions involving oxides of nitrogen

How is tropospheric ozone made?

1. NO2 is broken down by UV-A sunlight. This is a photochemical reaction.

2. The monatomic oxygen reacts with normal diatomic oxygen to produce ozone

Control

- Tropospheric ozone is a secondary pollutant, so levels can be controlled by reducing levels of the primary pollutants that produce it

- NO2 is produced by internal combustion engines, power stations, and other high temperature combustion involving air, so methods to reduce NO2 will reduce ozone levels, since it will prevent its formation