- Surbhi Jain
Ozone is a secondary pollutant, which means it is not directly emitted by traffic, industry, but it is formed on warm summer days by the influence of solar radiation on a cocktail of airborne pollutants. These ozone precursors are nitrogen oxides (NOx) and volatile organic compounds (VOC). Traffic is the main source (>50%) of ozone precursors.
However, ozone found in the troposphere, the layer of the atmosphere that extends from the earth’s surface to about 10 miles up, is deemed ground level or “bad” ozone. At ground level, ozone is an air pollutant that damages human health, vegetation, many common materials, and is a key ingredient of smog.
Many urban areas tend to have high levels of ground-level ozone. But even rural areas are subject to increased ozone levels because winds can carry ozone, and the pollutants that form it, hundreds of miles away from the original sources.
Ground level ozone is a common and widespread air pollutant that causes injury to the environment and human health. Exposure to ground level ozone can:
– irritate your respiratory system
– reduce lung function
– aggravate asthma
– inflame and damage cells that line your lungs
– aggravate chronic lung diseases
– cause permanent lung damage
For years, chlorofluorocarbons (CFCs) were used as a cooling device in freezers and air conditioners. Scientists discovered, however, that CFCs destroy the ozone layer – the layer that filters ultraviolet radiation from the sun. Ultraviolet radiation causes eye damage and skin cancer.
An international agreement commonly called the Montreal Protocol, signed in 1989 (see page 62), has helped stop the production of CFCs. If we keep to this agreement, ozone-depleting substances will stop being produced and the ozone layer will begin to repair itself over the next 100 years.
Scientists are unsure what is causing the ozone layer to falter at lower latitudes, but some have suggested that harmful chemicals may play a role. Researchers have also suggested that global warming is causing the circulation of the atmosphere to change and push more of the ozone away from the tropics, according to the release.