# Monday, June 23, 2008
                 

With summer here bringing the hot weather, air quality can be a big concern for Canadians, especially depending on where you live. Even for those who do not have respiratory problems, smog can be quite harmful and pose a health risk. For those with existing breathing problems, smog can be very dangerous.

Originally, the word smog was a definition of the mixture of smoke and fog. However, today smog defines the harmful mixture of gases and particles and is considered air pollution. Although it is usually visible as haze, it can also be invisible, due to particles that are too tiny to be visible. Weather factors such as humidity, as well as the type of pollutants determine what type of smog you experience on that certain day.

Many air pollutants combine to make smog. These pollutants are usually:

• Ground-level ozone: Ozone that is found high in the atmosphere is known as "good ozone"; it helps protects us from the sun's rays. However, ground level ozone is harmful to human health when it is inhaled. It can exacerbate respiratory problems for those who already have asthma, COPDS and other lung diseases, as well as those who suffer from cardiovascular diseases. Ground-level ozone forms when nitrogen oxide and volatile organic compounds from vehicle exhaust, factory emissions, etc. react with sunlight.
• Fine Particulate Matter (PM): A broad term for particles of liquids and/or solids that are air pollutants. PM 2.5 is matter that is very small but that can be breathed deeply into a person's lungs and remain there. It also stays in the air longer and travels further than other large particles. It is usually a result of vehicle exhaust, wood burning, paved and/or unpaved roads, construction, industry and forest fires. This tends to be the matter that makes people cough and/or sneeze as well as irritate the lungs, eyes, and/or throat. This also exacerbates breathing problems for those who already have respiratory disorders, and can actually cause heart attacks in those who have existing heart diseases.
• Sulphur Dioxide: A colorless gas that usually smells like burnt matches; this is a main ingredient in acid rain. When this combines with Volatile Organic Chemicals (VOC) and sunlight it creates ground-level ozone. The main causes for this gas are burning fossil fuels, industry mills, volcanoes and hot springs, and diesel vehicles. Exposure to sulphur dioxide can actually cause lung disease. It also irritates the nose and throat and causes breathing problems, as well lowering the lung's natural defense system. For those with cardiovascular and/or respiratory problems, exposure can make these worse.
• Nitrogen Oxides: This is caused by the same things that cause sulphur dioxide. Exposure can lower the body's resistance to lung infections as well as cause shortness of breath and irritation of the upper airways.
• Total Reduced Sulphur Compounds (TRS): A mixture of gases that usually smells like rotten eggs. This is common around areas that contain steel, pulp and/or paper mills, refineries and sewage treatment plants. Exposure usually results in headaches and/or nausea.
• Carbon Monoxide (CO): Odorless, tasteless, colorless gas that is poisonous at high levels. This is usually caused by burning fossil fuels in vehicles, the production of metals as well as emissions from heaters. At low levels, it can cause headaches, dizziness, lack of breath as well as slower reflexes and perception. High level exposure can result in unconsciousness, seizures, coma and respiratory failure that can result in death.
• Volatile Organic Compounds (VOC): These are gases in the vapors of gasoline, solvents as well as oil-based paints. They react with nitrogen oxides when it is sunny and/or warm and cause ground level ozone. The most common causes for VOCs are burning gasoline, the production of oil/gas products, wood burning and the evaporation of liquid fuels and solvents. Exposure can cause irritation to the eyes, nose and/or throat, headaches, nausea, loss of coordination and can also worsen lung and heart conditions.
• Polycyclic Aromatic Hydrocarbons (PAH): This is caused by the incomplete burning of carbon materials, i.e. wood, oil, garbage, coal, etc. Over 10,000 compounds make up this group of pollutants, which are responsible for lung irritation as well as skin rashes. Some PAHs have been found to cause cancer in laboratory animals when they are inhaled, ingested, and/or come into contact with skin. The major sources of PAHs are furnaces, exhaust from vehicles, cigarette smoke, wood burning, and fuel producing plants.

It is estimated that smog causes 5900 early deaths in Canada per year. The majority of these early deaths occur in Canadian major cities. While smog is harmful to everyone's health, those who are at high risk are:

• People already suffering from lung disease, i.e. asthma, emphysema and/or chronic bronchitis
• Children and teenagers as their lungs are still developing and they tend to be more active outdoors. Their smaller size also means that they are breathing in more pollutants per pound of body weight which leads to a higher absorption rate.
• Seniors
• Anyone who does vigorous outdoor activities during high smog days, especially those that work outside (construction workers, etc)

Although April – September is usually considered "smog season", it can and often does occur all year round. Ground level ozone generally is more prevalent in the warmer months, while fine particulate matter occurs during the winter. Everyone should be aware of how air quality affects their breathing, especially those listed above. Pay attention to air quality advisories, and try to avoid being outside during times when smog is prevalent.

For those who are sensitive to smog, or suffer from pre-existing heart and/or lung problems, try to stay inside in an air-conditioned environment. Air conditioning can help make breathing easier during the hot summer months, especially in hot and humid weather. If you can’t avoid being outside, make sure to avoid exerting yourself physically. Try to stay in shady areas, as well as roads and streets with heavy traffic. Drink plenty of water, and rest often. Exercise indoors, such as a gym or your home. Going outdoors in the morning instead of the afternoon is also advisable; the pollution levels are usually lower during this time period. If you have asthma, never leave home without your inhaler; chances of having an asthma attack are much higher when the air quality is poor.

Smog can have a negative affect on your health for up to a day after being exposed. If you experience problems breathing, make sure to contact your physician as soon as possible. For severe asthma attacks or other serious difficulties breathing, go to your nearest emergency room.

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