Page 119 - Geosystems An Introduction to Physical Geography 4th Canadian Edition

3.2
PHOTOCHEMICAL SMOG
Car exhaust contains pollutants such as carbon monoxide (CO), nitrogen dioxide (NO2), and volatile organic compounds (VOCs). When exhaust and the ultraviolet radiation in sunlight interact, photochemical reactions produce pollutants such as ozone and nitric acid, and peroxyacetyl nitrates (PANs). Ground-level ozone, the primary ingredient in photochemical smog, damages biological tissues. One in four children in U.S. cities is at risk of developing health problems from ozone pollution.
NO2 + H2O (water)
HNO3
(nitric acid)
Acid deposition
Solar radiation
Ultraviolet radiation
NO 2
(nitrogen dioxide)
O2
(molecular oxygen)
+ O
(atomic oxygen)
O3
(ozone)
NO + VOC
Ozone (O3)
Highly reactive, unstable gas
In the environment: Damages plants
Health effects: Irritates human eyes, nose, and throat
Volatile organic compounds
(VOCs)
In the environment: Prime agents of surface ozone formation
Peroxyacetyl nitrates (PANs)
In the environment: Major damage to plants, forests, crops Health effects: No human health effects
Carbon monoxide (CO)
Odourless, colourless, tasteless gas Health effects: Toxic; displaces O2 in bloodstream; 50 to 100 ppm causes headaches and vision and judgment losses
CO
(carbon monoxide)
(nitric oxide)
PANs
Photochemical smog
3.3
AIR POLLUTION: A GLOBAL PROBLEM
Stationary pollution sources, such as electric power plants and industrial plants that burn fossil fuels, produce large amounts of sulfur oxides and particulates. Concentrations of these pollutants are focused in the
Northern Hemisphere, especially over eastern China and northern India.
Particulate levels and population density in east Asia.
Describe: List the steps in the process by which vehicle exhaust leads to the increased ozone levels in smog.
October 2012 haze over eastern China [NASA].
Photochemical smog, Mexico City [Daily Mail/Rex/Alamy.]
GEOquiz
1. Predict: In relation to a coal-fired power plant, where might industrial smog and serious air pollution problems occur? What mitigation strategies exist? Explain.
2. Compare and Contrast: How are the pollutants carbon monoxide and nitrogen dioxide similar? How are they different?
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geosystems in action 3Air Pollution