|
HUMAN HEALTH AND ENVIRONMENT: PHOTOCHEMICAL SMOG
Photochemical smog is a brown, hazy mix of particulates and gases that forms when oxygen-containing compounds of nitrogen and hydrocarbons react in the presence of sunlight. Photochemical smog is sometimes called ozone pollution because ozone is created when vehicle exhaust reacts with sunlight. Such smog is most likely to develop on days when there is little wind and high traffic congestion. In most cases, it forms in areas that experience a temperature inversion, a weather condition in which a cool layer of air is trapped under a layer of warmer air, preventing the air from circulating. When gases such as the hydrocarbons and nitrogen oxides are released into the cool air layer, they cannot escape, and thus they remain suspended until wind conditions move away the warmer air layer. Sunlight filtering through the air causes chemical changes in the hydrocarbons and nitrogen oxides, which results in smog. Smog is more likely to be produced in valley regions blocked by hills or mountains - for example, the Los Angeles basin, Denver, and Tokyo.
The most noticeable adverse effects of exposure to smog are difficulty in breathing, burning eyes, headaches, and nausea. Long-term exposure to smog poses serious health risks, particularly for children, the elderly, pregnant women, and people with chronic respiratory disorders such as asthma and emphysema.
*310/277/5*
GENERAL HEALTH
|
