It can also affect the body's immune system, leaving adults and children more prone to colds and other illnesses.
The Ministry of the Environment samples and reports air quality readings to the public using the Air Quality Index, or AQI. If the air quality is poor, it will issue a "Smog Advisory".

What is Smog?

Smog is a mixture of air pollutants, including gases and particles that are too small to see. Particles from smog can lodge deep in our lungs. The smaller the particle, the deeper it lodges.

Ozone is the main ingredient of smog. Ozone is a gas that occurs both in the upper and ground level atmosphere. It can be good or bad depending on where it is found.

"Good" ozone occurs 16 to 48 kilometers above the earth's atmosphere. It protects us from the sun's harmful ultraviolet rays.

"Bad" ozone is found in the earth's lower atmosphere near ground level. It is formed when pollutants emitted by cars and industries react chemically in the presence of sunlight. Ozone smog is worse on hotter days, and smog particle concentrations are higher when it is hazy. On rainy days, air quality is better because the rain washes some of the pollution out of the air.

What Parents Need to Know

Becoming aware of smog is the first step, so listen and watch for the media smog alerts just as you do the UV index. Pay extra attention to especially smoggy days. A smog alert is also sometimes called a Smog Watch, Smog Warning, Air Quality Advisory, or Air Quality Alert. See below to subscribe to the Smog Alert Network.

When air pollution is having an effect on children, they tend to be less energetic and active. This is a natural reaction, but it is important to watch the youngest children for signs of strain.

Children are more at risk for reactions to smog than adults because they spend more time active outdoors in the summer. Children take more breaths per minute than adults, which means they inhale more polluted air. Babies and toddlers are especially at risk because their lungs are still developing and more sensitive to these pollutants.

Even healthy children, who are running or biking outside during high smog episodes may develop respiratory symptoms, such as throat irritation, coughing, wheezing, shortness of breath or chest tightness. Some children are more easily irritated by smog than others. Watch your child carefully. If the child is having trouble breathing, chest tightness, or is feeling unusually tired, activity and exposure should be reduced.

It is not only during a smog alert that air pollution can be dangerous to children. Many children, especially asthmatics, are affected by pollution at levels well below the smog alert level.

What Parents Can Do To Reduce Exposure To Smog And Its Potential Health Effects: