Smog is a mixture of air pollutants that contributes to the brownish haze we sometimes see on warm days from May to September. Smog is formed in the presence of heat as emissions released from vehicles, other industrial sources and human activities mix with contaminants already present in the air. Smog can blanket urban, suburban and rural areas, making it a significant health risk for all residents of Ottawa.

Composed mainly of ozone and fine particulate matter, smog can cause numerous adverse health effects. Some well-documented illnesses caused by exposure to smog include:

  • Breathing difficulties
  • Irritations of the lungs, eyes, nose and throat,
  • Chest tightness,
  • Coughing and wheezing,
  • Making asthma and existing heart and lung conditions worse

Although everyone can be affected by smog, children, seniors, and persons with heart and lung conditions are especially vulnerable. To caution people to protect their health, Smog Alerts are issued by Ontario's Ministry of the Environment and Environment Canada when forecasted weather conditions and air pollution levels support smog formation.

To help reduce smog and air pollution:
  • Reduce the use of your vehicle. Car, SUV and light truck emissions are the biggest smog contributors in the Ottawa area
  • Drive cleaner:
    • Regularly check your oil gauge
    • Avoid idling and traffic congestion
  • Conserve energy. Electricity produced from fossil fuels contribute to smog so:
    • Turn off lights when leaving the room
    • Buy energy-efficient appliances and light bulbs
    • Set the air-conditioning a few degrees warmer when no one is home
Seniors and smog
I am a senior, how can smog affect my health?
  • If you are a senior who suffers from heart disease or lung conditions such as asthma, emphysema, or chronic bronchitis, smog can make your symptoms worse
  • Smog can decrease the lung's working capacity. On a Smog Alert day, breathing can be more difficult. You may find your daily activities harder to do, and you may be more tired.
  • Smog reduces the respiratory system's ability to fight infections and remove foreign particles, increasing your risk of getting sick.
  • Seniors may be less able to sense the presence of ozone, and may have a delayed response to the early warning signs of smog exposure such as breathing difficulties, shortness of breath, and tightness in the lungs and chest.

How do I protect my health on a smog alert day?

  • Relax and take it easy. Avoid physical stress and activity.
  • Avoid strenuous outdoor work or exercise.
  • Stay indoors in a cool, well-ventilated place.
  • If you must be outside, try to schedule your activities early in the morning when pollution levels are lowest.
  • Avoid being outside around high traffic areas or during peak rush hour times to minimize your exposure to smog.
  • Avoid the sun and drink water and natural juices frequently.
  • If you experience symptoms such as tightness in your chest, wheezing, or shortness of breath, seek medical attention.

Adapted with permission, from the Smog Alert materials produced by the City of Toronto and by the Ontario Ministry of Health.

Air Quality Ontario (Ministry of Environment)

Children and smog

How can smog affect the health of my child?

  • Children are more likely to experience respiratory effects of smog such as wheezing, coughing, and shortness of breath because:
  • Children breathe in more air than adults. They also breathe faster than adults, especially during strenuous activity and play.
  • Children tend to breathe through their mouths and by-pass the natural filtering system in the nose. This allows large amounts of polluted air to get directly into their lungs.
  • Children spend more time outside than adults.
  • Smog increases a child's risk of getting sick. Children are more susceptible to infections than adults, and smog reduces the respiratory system's ability to fight infection and remove foreign particles.
  • Smog can make the symptoms of childhood asthma and allergies worse.

How do I protect the health of my child on a smog alert day?

  • Reduce your child's outdoor work, play or exercise.
  • Children with asthma and allergies should avoid being outside.
  • Plan activities for your child that can be done indoors in a cool, well ventilated place.
  • Schedule any "must be outside" activities early in the morning when pollution levels are lowest.
  • Children should avoid being outside during peak rush hour times or near high traffic areas. This will reduce their exposure to smog and other air pollutants.

Adapted with permission, from the Smog Alert materials produced by the City of Toronto and by the Ontario Ministry of Health.

Air Quality Ontario (Ministry of Environment)

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