Anyone can be affected by poor air quality or heat, regardless of age. However, it may have a greater impact on certain groups, for example people with asthma and those with heart problems or respiratory problems, such as emphysema and chronic bronchitis.
What is smog?
Smog is a yellowish haze that limits visibility in the atmosphere. Smog has a substantial impact on air quality and can have negative health effects.
- In summer, smog occurs on very hot, sunny days. It is composed mostly of fine particles and ozone. In the Greater Montreal area, pollutants are mainly released by cars and industrial processes. Also, forest fires that occur in summer in Québec cause atmospheric instability likely to result in deteriorating air quality in many regions, including Laval.
- In winter, smog is caused by a high concentration of fine particles. They are present all year long, but can increase in winter due to wood heating.
The Air quality health index is classified into 4 categories: low risk, moderate risk, high risk and very high risk. The Air quality health index 
measures air quality in relation to your health.
To find out about the quality of the air in your area
Symptoms
Exposure to smog can cause the following symptoms:
- Itchy eyes and tearing
- Runny nose and sinus irritation
- Sore throat and mild cough
- Headache
The next symptoms are less common but more severe, and could require medical follow-up:
- Shortness of breath
- Wheezing (including asthma attacks)
- Severe cough
- Dizziness
- Chest pain
- Heart palpitations
People concerned about their own or a loved one’s health can contact Info-Santé by dialing 811. In case of a medical emergency, call 911.
People at risk
SMOG can affect the health of people of all ages, but especially:
- People with respiratory problems such as emphysema or chronic bronchitis
- People with asthma
- People with heart problems
- Older adults
- Young children
- Pregnant women
To reduce exposure to smog:
- Close the windows and doors of your residence, as long as the interior temperature remains tolerable.
- Turn off the air exchange system or set it to recirculate to prevent outdoor air from entering into your residence.
- Move your activities indoors, if possible.
- Avoid outdoor physical activities as much as possible.
These recommendations can be implemented in educational facilities, daycares and other workplaces.
The best way to protect yourself from the risk of wildfire smoke is to reduce exposure by staying indoors. However, when this is not possible, wearing a N95 mask can reduce exposure and health risks associated with very poor air quality.
NOTE : Medical or fabric masks, as well as damp cloths, are ineffective against fine particles caused by forest fires.
Instructions for workplaces
- CNESST - General recommendations for workplaces
- Réseau de santé publique en santé au travail - Information, preventive measures, and recommendations for employers (in french only)
To contact the occupational health team.