Table of Contents
How does ozone become a secondary pollutant in the troposphere?
Ozone, unlike the other criteria pollutants, is not emitted directly into the air by any one source. Ground-level ozone is a secondary pollutant. It is formed through chemical reactions of other molecules already in the air, specifically nitrogen oxides (NOx) and volatile organic compounds (VOCs).
What is tropospheric ozone pollution?
Ground level or tropospheric ozone is created by chemical reactions between oxides of nitrogen (NOx gases) and volatile organic compounds (VOCs). The combination of these chemicals in the presence of sunlight form ozone. Ozone in the troposphere is considered a greenhouse gas, and may contribute to global warming.
Is troposphere ozone a secondary pollutant?
Tropospheric ozone (O3) is a secondary pollutant that results from photochemical reactions of NOx and VOCs involving generally well-understood reactions (Jenkins and Clemitshaw, 2000).
How does ozone in the troposphere form?
Tropospheric ozone is formed by the interaction of sunlight, particularly ultraviolet light, with hydrocarbons and nitrogen oxides, which are emitted by automobile tailpipes and smokestacks. To form, ozone needs sunshine to fuel the chemical reaction.
What is the function of ozone present in the troposphere?
Ozone protects life on Earth from the Sun’s ultraviolet (UV) radiation. In the lower atmosphere (the troposphere) near the Earth’s surface, ozone is created by chemical reactions between air pollutants from vehicle exhaust, gasoline vapors, and other emissions.
Where is ozone considered a pollutant?
The ozone layer found high in the upper atmosphere (the stratosphere) shields us from much of the sun’s ultraviolet radiation. However, ozone air pollution at ground level where we can breathe it (in the troposphere) causes serious health problems.
What is the role of ozone in the troposphere?
In the stratosphere, ozone molecules play an important role – absorbing ultraviolet radiation from the Sun and shielding Earth from dangerous rays. But in the troposphere, near ground-level, ozone molecules are both air pollutants, threatening the health of living things, and greenhouse gases, trapping heat and contributing to climate change.
How is ozone harmful to plants and animals?
Closer to Earth in the troposphere (the atmospheric layer from the surface up to about 10 km), ozone is a harmful pollutant that causes damage to lung tissue and plants. The amounts of “good” stratospheric and “bad” tropospheric ozone in the atmosphere depend on a balance between processes that create ozone and those that destroy it.
Where does ozone come from in the air?
Unlike most other air pollutants, ozone is not directly emitted into the air. Tropospheric ozone is formed by the interaction of sunlight, particularly ultraviolet light, with hydrocarbons and nitrogen oxides, which are emitted by automobile tailpipes and smokestacks. In urban areas, high ozone levels usually occur during warm summer months.
When is ozone considered to be a pollutant?
The NIOSH recommended exposure limit for ozone is 0.1 ppm (0.2 mg/m 3 ). According to NIOSH, Ozone levels of 5 ppm or higher are considered immediately dangerous to life or health. How can you tell if you are being affected by ozone?