Smog can, in fact, be harmful to your health.
You may remember that the hole in the ozone layer was a topic of heated debate some years ago. That left many of us with the impression that the depletion of ozone is bad; thus the creation of ozone must be good. However, the ozone layer of the atmosphere is far above the earth, and is not breathed by humans. Its function is to filter out harmful ultraviolet rays from the sun, shielding the earth from excessive warming and other harmful irradiative effects. But ozone that forms at ground level is different.
Ground-level ozone is the primary ingredient in smog. It is formed when certain pollutants mix with sunlight. Because of the water content in smog, it hangs lower in the atmosphere – low enough to be breathed by humans.
Some of the pollutants that are most likely to form ozone when mixed with sunlight are volatile organic compounds (VOCs), which are found in household and industrial paints, and nitrogen oxide, which is an emission associated with the burning of fossil fuels, the management of soil on farms, and other human activities. Nitrogen oxide can also occur naturally, particularly in tropical forests.
Breathing ground-level ozone is associated with respiratory problems, congestion, and a compromised immune system.
2. Particulate Matter
As the term implies, particulate matter is made from particles. Another ingredient in smog, these particles are dust, dirt, smoke, or other particles that are formed via chemical reactions in the atmosphere.
Whether these particles are fine or coarse, their effects on the lungs are uncomfortable and potentially harmful. The finer the particles, however, the more likely they are to damage the lungs – fine particles can be inhaled deep into the lung tissue where they can cause chronic coughing, wheezing, and other uncomfortable symptoms.
The breathing of smog in general has been associated with headaches, fatigue, nausea, and allergy symptoms. Children, elderly people, asthmatics and the chronically ill are particularly susceptible to the negative effects of breathing smog. While scientists are still researching to determine long-term effects, the fact that smog is not healthy to breathe is generally accepted as fact.