Toxic Chemicals in Our Environment
Indoor air pollution
Indoor air pollution can affect you at home, work, or even places you visit. It can increase your risk of a respiratory disease, such as asthma, allergies, and lung cancer. Indoor air pollution can be worse in winter, when windows are shut tight and less fresh air can circulate. A study found that three pollutants commonly found in houses have the greatest effect on health:footnote 1
- Formaldehyde, which is released mainly by building materials.
- Acrolein, which comes from heating cooking oil to high temperatures and from cigarette smoke.
- Tiny particles, called respirable particulates, that can get into the lungs. Common sources of respirable particulates are tobacco smoke and diesel exhaust.
See tips for reducing indoor air pollution.
One of the most common and toxic indoor air pollutants is cigarette smoke. Experts believe about 85% of lung cancers are caused by cigarette smoke.footnote 2 Smoking, or even inhaling second-hand smoke, increases your risk of heart attack and stroke.
Tobacco smoke contains many chemicals, some of which can cause cancer. If you are a non-smoker and household members or co-workers will not stop smoking around you, ask that they smoke only in well-ventilated or isolated areas. Never smoke around children or allow them to be exposed to cigarette smoke, especially if they have asthma or allergies.
Exposure to cigarette smoke causes wheezing, coughing, and extra mucus (phlegm) in many children. Second-hand smoke also can cause fluid to build up in the inner ear, which can cause ear infections. Lower respiratory infections, such as pneumonia and bronchitis, are also risks. Sometimes these types of infections become serious enough to require a hospital stay, especially when they develop in babies and young children.footnote 3
Babies who are exposed to second-hand smoke are at increased risk for sudden infant death syndrome (SIDS).footnote 4
Cigarette smoke may cause asthma in children.footnote 4 Also, children with asthma who are exposed to cigarette smoke have more attacks and more severe symptoms than other children with asthma.footnote 4
See information on the increased impact of environmental illnesses on children. For example, in recent years, the number of children with asthma has more than doubled, and environmental causes are suspected.
Wood stoves and gas ranges
Wood stoves that are not properly maintained and vented can give off tiny particles (particulates) and gases, including carbon monoxide, nitrogen, and hydrocarbons. Children in homes heated with wood stoves are at increased risk for respiratory problems. Gas ranges, particularly when they are not well-vented or when they are used as a source of heat, may produce nitrogen dioxide, which can cause respiratory problems. Consider changing to an electric stove.
If your gas stove has a persistent yellow flame, it may be improperly adjusted. Ask your gas company to adjust the burners so the flame tips are blue. If you're planning to buy a new gas range or stove, consider one that does not use a pilot light.
If you use a wood stove, make sure the stove doors fit tightly. Burn only aged or cured wood that is completely dry. Never burn pressure-treated wood because it is treated with chemicals.
Have chimneys, flues, and furnaces inspected each year.
For more information, see the topic Carbon Monoxide Poisoning.
Exposure to building materials, products used for home improvement, and textiles can cause health problems. For example, particle board, insulation, carpet adhesives, and other household products emit formaldehyde, which can cause nausea, respiratory problems, dry or inflamed skin, and eye irritation. Newly built homes and the confined spaces of mobile homes can be a particular problem. Using environmentally safe products—such as paint that contains a low level of or no volatile organic compounds (VOCs)—can reduce the chemical load on your body.
Sick building syndrome
Experts coined the term "sick building syndrome" to describe acute symptoms that occur only during time spent in a particular building and that cannot be explained by any specific illness or cause. Symptoms include headache, dry cough, dry or itchy skin, dizziness, nausea, difficulty concentrating, fatigue, sensitivity to odours, and irritation of the eyes, nose, or throat. Typically the symptoms improve after you leave the building.
Poor ventilation that restricts fresh air flow inside can be a cause of sick building syndrome. Carpet, adhesives, upholstery, manufactured wood, pesticides, and cleaning fluids can give off volatile organic compounds (VOCs), including formaldehyde. High concentrations of VOCs can cause cancer. Unvented gas and kerosene space heaters, wood stoves, fireplaces, and gas stoves can produce carbon monoxide and nitrogen dioxide. These gases can harm your health.
Also, chemicals that get into a building from the outside can cause sick building syndrome. Pollutants from cars and trucks and exhaust from plumbing vents and building machinery can enter a building through vents.
Bacteria, moulds, viruses, and other biological contaminants
Bacteria and moulds can breed in stagnant water that builds up in humidifiers, drain pans, and ducts, or where water collects on carpet, ceiling tiles, and insulation. Humidifier fever is an illness caused by toxins from microorganisms that grow not only in large heating and cooling systems in buildings but also in home systems and humidifiers. Legionella pneumophila is an indoor bacterium that can cause Legionnaires' disease.
Some viruses can survive on household surfaces, such as counters or floors, or they can get spread through the air when an infected person sneezes or coughs. You can help control viruses by:
- Cleaning household surfaces with a disinfectant.
- Having adequate ventilation in your house.
- Having anyone with a viral infection, such as a cold or influenza (flu), cough or sneeze into the bend of the elbow or into a tissue.
Pet dander, pollen, dust mites, moulds, and rat and mouse urine are allergens that can cause asthma attacks, allergic rhinitis, and other lung problems. Symptoms of illness caused by biological contaminants include sneezing, watery eyes, shortness of breath, lethargy, dizziness, and digestive problems.
Exposure early in life to indoor allergens such as moulds may increase the risk of allergies or asthma.footnote 5 Allergies to moulds can also make asthma attacks worse or cause other breathing problems.
Keep your home clean and as free from dust as possible to help reduce allergens. There are many ways to control dust and dust mites in your home, such as washing bedding in hot water to kill dust mites and eliminating furnishings, such as drapes, that collect dust. Also, there are many steps you can take to control animal dander and other pet allergens.
Exhaust fans that vent to the outdoors and are installed in kitchens and washrooms can help get rid of moisture that allows microorganisms, including moulds, to grow. When modern building materials get wet, they provide an ideal place for the growth of moulds, which can make asthma attacks worse and may cause other respiratory symptoms. Ventilating attic and crawl spaces and keeping humidity levels below 50% can help prevent moisture buildup in building materials. There are other ways to control indoor moulds, such as preventing leaks, removing wet materials, storing fireplace wood outside the home, and using a dehumidifier during humid weather.
Keep humidifiers clean and refill them daily with fresh water. Frequently clean evaporation trays in air conditioners, dehumidifiers, and refrigerators. Water-damaged carpets and building materials can also have moulds and bacteria in them. It is difficult to get rid of bacteria or moulds. So, if possible, replace or remove water-damaged items from your home.
You can also:
- Remove carpets and replace them with hardwood or tile floor.
- Have sofas with covers that can be removed and washed.
- Use blinds instead of drapes, because they collect less dust.
- Have air filters in some rooms, especially in the bedrooms.
For more information, see:
Many of the products you use to clean your home or use for hobbies and home improvement projects contain potentially hazardous chemicals. Some can be toxic and in sufficient doses can cause eye and respiratory problems, headaches, dizziness, visual problems, and memory impairment. One of the most important ways you can protect yourself is by following the instructions on the label. When you use cleaning or other products, be sure to open windows or use an exhaust fan to provide good ventilation. Never mix household chemicals, such as chlorine bleach and ammonia. Some mixtures can create toxic fumes that can be fatal.
It's better to use environmentally safe products. Vinegar, lemon juice, boric acid, or baking soda can be used instead of store-bought household cleaners. And they are less damaging to you and to the environment.
Be especially careful with products containing methylene chloride, including paint strippers, adhesive removers, and aerosol spray paints. If you use products that contain this chemical, make sure you have adequate ventilation or use them outdoors, if possible. Also, wear gloves to avoid skin contact. But whenever you can, use environmentally safe products instead.
Avoid exposure to benzene, which can cause cancer. Benzene is found in tobacco smoke, fuels, and paint supplies. Also, try to limit your exposure to newly dry-cleaned clothing or furnishings. Dry-cleaned goods may emit perchloroethylene (also known as tetrachloroethylene) and trichloroethylene. These chemicals may cause skin rashes, headaches, and dizziness.footnote 6 If your clothes emit a strong odour when you pick them up from the cleaners, they may not have been dried properly and can release more of this chemical. After removing the protective plastic from the clothes, hang them outside, if possible. Consider finding a dry cleaner that uses less toxic chemicals.
Asbestos is an insulating material commonly used from the 1950s to 1970s for soundproofing and to cover floors and ceilings, water pipes, and heating ducts. When it becomes crumbly or frayed, asbestos fibres can be released into the air. Breathing asbestos fibres may cause lung cancer, asbestosis (scarring of the lung tissue), or mesothelioma.
Radon is a colourless, odourless radioactive gas that can enter your home through cracks in concrete walls and floors and through floor drains. The most common source of radon is uranium that normally exists in the soil or rock on which homes are built. Problems show up when the concentration of radon builds up in a home or building. Both old or new homes can have problems with radon even if they don't have a basement.
Exposure to radon gas is the second leading cause of lung cancer. (Tobacco smoke is the leading cause.) The risk of radon-associated lung cancer is much higher for smokers than non-smokers.footnote 7
You cannot smell or see radon. But it's easy to test for it with a do-it-yourself kit available on the Internet or from home improvement stores. You can also contact your provincial environmental office for advice. For more information, see the topic Radon.
Treatment for indoor air pollution
How you react to indoor air pollutants depends on your age, health, and how sensitive you are to certain chemicals or biological pollutants, such as bacteria or moulds. Treatment can be as simple as removing and limiting your exposure to toxic chemicals in your home. In some cases, serious illnesses—such as cancer, heart disease, and respiratory disease—can develop after long-term and repeated exposures. With such long-term exposures, treatment may be extensive, depending on the type of illness.
Outdoor air pollution
Polluted air comes from many sources, such as factories, cars, buses, trucks, and power plants. And there are other sources that you may not think of, such as dry cleaners, wildfires, and dust. Dirty air is a threat to your health. And it also damages crops, trees, water, and animals.
There are at least six major components of air pollution:
- Ozone. Ozone is a gas that exists at ground level as well as miles above the earth. It's made by a chemical reaction between nitrogen oxides and volatile organic compounds (VOCs) in the presence of heat and sunlight. "Good" ozone occurs naturally about 15 to 50 kilometres above the earth's surface. There, in the stratosphere, it forms a layer that protects the earth's surface from the sun's harmful rays. At ground level, "bad" ozone (smog) exists. Exhaust from vehicles, industrial emissions, gasoline vapours, and chemical solvents are major sources of nitrogen oxides and VOCs. Add sunlight and hot weather to the mix, and harmful concentrations of ozone may develop. Because of the heat factor, ground-level ozone is a summertime air pollutant that can be dangerous, especially for people with respiratory illnesses. Problems include:
- Irritation of the lungs.
- Coughing, wheezing, and pain when taking a deep breath, and breathing problems while exercising.
- Permanent lung damage from repeated exposure.
- Aggravated asthma, increased susceptibility to pneumonia and bronchitis, and reduced lung capacity.
- Particulates. Particulates include dust, dirt, soot, smoke, and liquid droplets found in the air. They come from many sources, such as vehicles, factories, construction sites, unpaved roads, and burning wood. Other particulates are formed when gases from burning fuels react with water vapour and sunlight. This can result from the combustion of fuels in motor vehicles and from industrial and power plants. Very small particulates that can get into your lungs are especially harmful to your health and may increase your risk of lung cancer and heart problems.footnote 8, footnote 9 Particulates in the air you breathe can cause:
- Asthma attacks.
- Chronic bronchitis.
- Coughing and difficult or painful breathing.
- Reduced lung function.
- Eye, nose, and throat irritation.
- Carbon monoxide. In cities with lots of traffic, most of the carbon monoxide put into the air comes from vehicle exhaust. It also comes from manufacturing processes, wood burning, and forest fires. Indoor sources include cigarettes and space heaters. Carbon monoxide reduces the body's ability to deliver oxygen to tissues and organs, such as the heart and brain. It is especially dangerous for people who have heart problems. Carbon monoxide can be fatal to those exposed to extremely high levels. Every year carbon monoxide poisoning is a leading cause of deaths from toxic chemicals. People with carbon monoxide poisoning may have:
- Nitrogen dioxide. When mixed with other particles in the air, nitrogen dioxide can often be seen as a reddish brown layer over many urban areas. Sources are fuels burned by vehicles, electric utilities, and industrial plants. Nitrogen dioxide is one of the nitrogen oxides, a group of highly reactive gases that contain various amounts of nitrogen and oxygen. Studies show that nitrogen dioxide may increase your risk of heart problems, such as heart failure.footnote 9 Nitrogen oxides cause many problems, including:
- Breathing problems.
- Acid rain, which is made when nitrogen oxides and sulfur dioxide react with other substances in the air and form acids. The acids then fall to earth as rain, snow, dry particles, or fog.
- Toxic chemicals. Nitrogen oxides mix with common organic chemicals and even ozone to create toxic chemicals that can cause biological mutations.
- Visibility impairment. Nitrogen dioxide and nitrate particles block light transmission and reduce visibility in urban areas.
- Sulfur dioxide. This gas is formed when fuels containing sulfur are burned. Examples are when coal and oil burn, when gasoline is extracted from oil, or when metals are extracted from ore. Sulfur dioxide is put into the air when fossil fuel is burned, such as by coal-fired power plants. Other sources are industries that create products from metallic ore, coal, and crude oil or those that burn coal or oil, such as petroleum refineries or metal processing facilities. Sulfur dioxide causes:
- Health problems for people with asthma and heart conditions.
- Acid rain.
- Damage to forests and crops.
- Damage to fish in streams and lakes.
- Lead. Leaded gasoline used to be the main source of lead in the air. But because leaded fuels have been phased out, the main sources of lead emissions are metals-processing facilities, especially lead smelters. Lead may cause serious health problems, including:
- Damage to kidneys, liver, brain, nerves, and other organs. Lead may also cause osteoporosis and reproductive problems. Excessive exposure can cause seizures, intellectual disability, behavioural disorders, memory problems, and mood changes. Low levels of lead cause brain and nerve damage in young children and fetuses, which can lead to learning problems and low IQ.
- High blood pressure and increases in heart disease.
For more information, see the topics Carbon Monoxide Poisoning and Lead Poisoning.
Your drinking water may come from a public water system or a well, or you may use bottled water. Provincial, territorial, federal, and municipal governments share the responsibility for keeping public water systems safe. But water from a well may need testing to make sure it is safe to drink. You may be able to use a water filter or a water purification system to provide safe water. It is important for you to know where your drinking water comes from, if it is treated, and if it's safe to drink.
- If you have a private well, make sure that it is not located too close to a septic system. You are responsible for getting your well water tested to see if it is safe to drink. You may want to get your well water tested regularly to make sure it is safe.
- If you are on a public water system, a local agency will let you know when there is a problem with the water. Follow all instructions for purifying your water (commonly called "boil orders") or for using other water sources. Authorities will tell your community when it is safe to drink from the public water supply again.
- If you use bottled water, it may be difficult to be sure the water is safe. Health Canada and the Canadian Food Inspection Agency share responsibility for regulating bottled water. Health Canada sets health and safety standards for bottled water. The Canadian Food Inspection Agency handles inspection and enforcement to meet these standards. If a brand of bottled water is found to be contaminated, Health Canada can make sure it is no longer sold. If you use bottled water, try to get it from a company that has a good reputation.
Be aware that water can be contaminated by organisms such as bacteria or fungi, by chemicals such as pesticides, and by metals such as lead or mercury.
Exposure to pesticides may come from residual agricultural pesticides in foods; from household or workplace products used to control rodents, insects, and termites; and from disinfectants and fungicides. The most likely ways you are exposed are small quantities of pesticides in the foods you eat and by direct contact with surfaces (such as plants, soils, or structures) where pesticides have been used.
If not used properly, both workplace and household pesticides can be dangerous. Exposure to high levels of some pesticides can cause headaches, dizziness, muscle twitching, nausea, weakness, and tingling sensations. Some experts believe that some pesticides may cause cancer or damage to the central nervous system.footnote 10 For agricultural workers, exposure to pesticides has been linked with an increased risk of non-Hodgkin's lymphoma.footnote 11
Pesticide exposure during pregnancy has been associated with miscarriage, fetal death, and early childhood cancers such as acute lymphoblastic leukemia (ALL). Indoor use of pesticides increases children's risk of brain tumours, ALL, and birth defects. Children can be poisoned by stored pesticides, so these should always be kept out of reach. Health Canada recommends that children have as little exposure to pesticides as possible.footnote 12
See tips for reducing pesticide exposure in your home, such as reducing your use of lawn and garden pesticides and limiting your exposure to moth repellents.
Mercury in fish
For most people, the level of mercury absorbed by eating fish and shellfish is not a health concern. But in a fetus or young child, this can damage the brain and nerves (nervous system). Because of the mercury found in fish, Health Canada advises women who may become pregnant, pregnant women, nursing mothers, and young children to avoid eating fish high in mercury and to eat limited amounts of fish and shellfish that are lower in mercury.footnote 13 For more information, see the topic Avoiding Mercury in Fish.
Chemicals from plastics and other products
Some people are concerned about bisphenol A (BPA). This is a chemical found in some types of plastic (polycarbonate) bottles. BPA also is used to line the inside of some types of food cans and other containers. A study has shown that people who have high levels of BPA in their urine have a greater risk for heart disease.footnote 14 And a group of experts concluded that bisphenol A may have some effect on the behaviour, brain, and prostate gland of a developing baby (fetus) or young child.footnote 15, footnote 16 Health Canada has banned plastic baby bottles that contain the chemical bisphenol A (BPA). Don't use bottles marked with the number 7 or the letters "PC" near the recycle symbol. You can use glass or BPA-free plastic bottles instead. Visit the Government of Canada's webpage on bisphenol A at www.canada.ca/en/health-canada/services/food-nutrition/food-safety/packaging-materials/bisphenol.html to learn more information.
In the past, a group of substances called polychlorinated biphenyls (PCBs) were used in electrical equipment, plastics, and dyes. Although they are no longer made in North America, they remain in the environment. Exposure to PCBs has been linked to health problems, especially mental functions such as memory and attention in children.footnote 17 Exposure to PCBs also has been linked to sperm problems in men.footnote 18 Visit the Government of Canada's webpage on PCBs at www.canada.ca/en/health-canada/services/healthy-living/your-health/environment/pcbs.html to learn more information.
Chemicals called phthalates may cause problems with the reproductive organs of infants and young children, especially boys. Phthalates can be found in some plastic items (such as some medical devices) and in products such as powders, lotions, and shampoos.footnote 19, footnote 20
Sand or silica dust
Silicosis is a lung disease caused by breathing in tiny pieces of sand or silica dust. Silica is a common mineral found in sand and rock. Breathing in silica may be a risk in certain jobs, such as construction, mining, rock drilling, sandblasting, and masonry. Silicosis may also be a risk for people who work with glass or ceramics.
Silicosis can cause breathing problems and damage to the lungs. Symptoms may appear many years after exposure to silica. But they can occur much sooner when there is a high level of exposure.
Silicosis can't be cured, but medicines can help manage the symptoms and treat problems such as infections.
To prevent silicosis, you can do things to avoid dust exposure. For example, you can wear a mask or other device that prevents the fine silica dust from getting into your lungs.