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Indoor air pollution
Indoor air pollution can affect you at home, work, or even places you visit. It is a common source of respiratory diseases, including asthma, allergies, and lung cancer. It can be worse in winter, when windows are shut tight and less fresh air can circulate.
One of the most common and toxic indoor air pollutants is cigarette smoke. Experts believe more than 87% of lung cancers are caused by cigarette smoke.
Smoking, or even inhaling secondhand smoke, increases your risk of heart attack and stroke.
Tobacco smoke is a mixture of more than 4,700 compounds. Smoke from the smoldering end of a cigarette contains more cancer-causing chemicals than the smoke exhaled by a smoker.
If you are a nonsmoker and household members or coworkers 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 an extra mucus (phlegm) in many children. Secondhand 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 hospitalization, especially when they develop in babies and young children.
Babies who are exposed to secondhand smoke are at increased risk for sudden infant death syndrome (SIDS).
Cigarette smoke may cause thousands of children each year to develop asthma. 6 Also, children with asthma who are exposed to cigarette smoke have more attacks and more severe symptoms than other children with asthma.
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.
- Woodstoves and gas ranges
Woodstoves that are not properly maintained and vented can give off gases, including carbon monoxide, nitrogen, particulates, and hydrocarbons. Children in homes heated with woodstoves 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.
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 woodstove, make sure the doors fit tightly. Only use 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, particleboard, 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.
- Sick building syndrome and building-related asthma
Experts coined the term "sick building syndrome" to describe acute symptoms that occur only during time spent in a particular building that can't be explained by any specific illness or cause. Symptoms include headache, dry cough, dry or itchy skin, dizziness, nausea, difficulty concentrating, fatigue, sensitivity to odors, 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, copy machines, 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, woodstoves, fireplaces, and gas stoves can produce carbon monoxide and nitrogen dioxide.
Outdoor sources of chemicals can also cause sick building syndrome. Pollutants from cars and trucks and exhaust from plumbing vents and building machinery can enter a building through vents.
Building-related asthma, in contrast, is the term used when symptoms of a diagnosed illness can be linked directly to airborne contaminants within a building. Symptoms include cough, chest tightness, and wheezing. Leaving the building may not immediately improve the symptoms.
- Bacteria, molds, viruses, and other biological contaminants
Bacteria, molds, and viruses can breed in stagnant water that accumulates 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 in large heating and cooling systems in buildings, but they can also be found in home systems and humidifiers. Legionella pneumophila is an indoor bacterium that can cause Legionnaires' disease.
Pet dander, pollen, dust mites, molds, and rat and mouse urine are allergens that can cause asthma, 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.
Although studies so far have been inconclusive, evidence is accumulating that exposure to indoor allergens such as molds early in life can result in a persistent allergic reaction. 7 Allergies to molds can also make asthma attacks worse or cause asthmalike symptoms.
Keeping your home clean and as free from dust as possible can 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. Similarly, 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 bathrooms can help get rid of moisture that allows microorganisms including molds to grow. When modern building materials get wet, they provide an ideal environment for the growth of molds, which can worsen asthma attacks 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 molds, such as preventing leakage, removing wetted 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 harbor molds and bacteria. Because it is difficult get rid of bacteria or molds, if possible replace or remove water-damaged items from your home.
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 using cleaning or other products, make sure to open windows or use an exhaust fan to provide good ventilation. Never mix household chemicals, such as chlorine and ammonia. Some mixtures can create toxic fumes that can be fatal.
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 to have adequate ventilation or use them outdoors, if possible.
Avoid exposure to benzene, which can cause cancer. Benzene is found in tobacco smoke, stored fuels and paint supplies, and vehicle exhaust inside garages. Also, try to limit your exposure to newly dry-cleaned clothing or furnishings. Dry-cleaned goods emit perchloroethylene (also known as tetrachloroethylene). If your clothing emits a strong odor 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 to dry, 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. If it is in good condition, it's generally not a health risk, but once it becomes crumbly or frayed, asbestos fibers can be released into the air. Breathing asbestos fibers may cause lung cancer, asbestosis (scarring of the lung tissue), or mesothelioma.
Radon is a colorless, odorless 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 arise when concentrations of radon build 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 12 times higher for smokers than nonsmokers. 8
You cannot smell or see radon, but it's easy to test for with a do-it-yourself kit available in hardware stores or through the U.S. Environmental Protection Agency (EPA). For more information, see the topic Radon.
Polluted air comes from many sources. There are the usual suspects: factories, cars, buses, trucks, and power plants. But there are sources 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 six major components of air pollution:
OzoneOzone 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 10 to 30 miles above the earth's surface. There, in the stratosphere, it forms a protective layer from the sun's harmful rays. At ground level, "bad" ozone (smog) exists. Exhaust from vehicles, industrial emissions, gasoline vapors, 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 that causes inflammation much like a sunburn.
- Coughing, wheezing, 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.
ParticulatesParticulates 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 wood burning. Other particulates are formed when gases from burning fuels react with water vapor and sunlight. This can result from the combustion of fuels in motor vehicles and from industrial and power plants. Particulates in the air you breathe can cause:
- Aggravated asthma.
- Coughing and difficult or painful breathing.
- Chronic bronchitis.
- Decreased lung function.
- Eye, nose, and throat irritation.
Carbon monoxide.In cities with lots of traffic, most of the carbon monoxide released 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. People with carbon monoxide poisoning may develop:
- Headaches, irritability, or loss of consciousness.
- Difficulty working, learning, or performing complex tasks.
- Aggravation of heart problems, such as angina, heart failure, and coronary artery disease
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. Nitrogen oxides cause several problems, including:
- Respiratory problems associated with ground-level ozone.
- Acid rain, which is created 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.These gases are formed when fuels containing sulfur are burned. Examples are coal and oil burning, the process of extracting gasoline from oil, or when metals are extracted from ore. More than 13 million tons of sulfur dioxide per year is emitted into the air by electric utilities, especially those that burn coal. 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, mental retardation, behavioral 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.
Exposure to pesticides may come from residual agricultural pesticides in foods or 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 liver and central nervous system. 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 tumors, ALL, and birth defects. Children can be poisoned by stored pesticides, so these should always be kept out of reach. For agricultural workers, exposure to pesticides has been associated with an increased risk of non-Hodgkin's lymphoma.