How Is Photochemical Smog Dangerous?

Photochemical smog, haze that results from sunlight reacting with emissions from automobiles and coal-burning power plants, poses health dangers to individuals with chronic health conditions involving the lungs and heart, according to the Science Education Resource Center at Carleton College.

Smog Components

• The components of photochemical smog include nitrogen dioxide, ozone and other organic compounds that can irritate the nasal passages and the eyes.

Seasonal Factors

• Photochemical smog presents a greater problem in the summer because of more abundant light conditions which encourage its formation.

Wind and Geography

• Photochemical smog also tends to form in calm, non-windy conditions and during temperature inversions, when warm air traps cooler air beneath it. Cities near mountains, like Los Angeles, often have these conditions.

Vulnerable Populations

• Besides those with heart disease and respiratory conditions like asthma, people at risk include the elderly and very young and those who do manual labor and exercise outdoors on days with heavier smog.

Greater Industrialization

• Although photochemical smog has not yet caused serious catastrophes, growing populations and industrial development around the world have the potential for increasing photochemical smog and its hazards to vulnerable populations.