In many areas around the word, smog has reached extraordinary levels.  Some governments have quickly reacted with severe measures in response to the problem.

The word smog is a combination of the words smoke and fog.  The term was invented by a Glasgow public health official, Des Voeux.

A Sketch of a Smoggy City.  Image Credit: La Jolla Country Day School.

Smog causes a smoky dark atmosphere to arise over cities.  It decreases visibility, and creates a haze throughout the area.

Numerous studies have monitored smog throughout the world.  Some of the world's dirtiest cities have millions of inhabitants, all of whom are threatened by the smog.

Modern Los Angeles suffers severely from smog, as London did in the 19^th century.  These two areas released certain chemicals into the air and created a foggy atmosphere.  In London, where fog levels have now fallen far below those of years ago, people were often unable to see their hands and sometimes could not walk around.

It took a long time for governments to act to control smog.  The Clean Air Act of 1970 in the United States limited legal smog levels.  The Environmental Protection Agency now measures levels of smog and regulates smog producers.

Despite government action to reduce them, smog levels remain very high in many cities.  Even those areas that do successfully reduce smog may be the victims of smog blown in from other locations.

Smog - Causes
Smog - Effects
Smog - Solutions