Health Effects From Biological Contaminants
Some biological contaminants trigger allergic reactions, including hypersensitivity pneumonitis, allergic rhinitis, and some types of asthma. Infectious illnesses, such as influenza, measles and chicken pox, are transmitted through the air. Molds and mildews release disease-causing toxins. Symptoms of health problems caused by biological pollutants include sneezing, watery eyes, coughing, shortness of breath, dizziness, lethargy, fever and digestive problems.
Allergic reactions occur only after repeated exposure to a specific biological allergen. However, that reaction may occur immediately upon re-exposure, or after multiple exposures over time. As a result, people who have noticed only mild allergic reactions, or no reactions at all, may suddenly find themselves very sensitive to particular allergens. Some diseases, such as humidifier fever, are associated with exposure to toxins from microorganisms that can grow in large buildings’ ventilation systems. However, these diseases can also be traced to micro-organisms that grow in home heating and cooling systems and humidifiers. Children, elderly people, and people with breathing problems, allergies, and lung diseases are particularly susceptible to disease-causing biological agents in the indoor air. Mold, dust mites, pet dander, and pest droppings or body parts can trigger asthma. Biological contaminants, including molds and pollens, can cause allergic reactions for a significant portion of the population. Tuberculosis, measles, staphylococcus infections, Legionella and influenza are known to be transmitted by air.
Combustion appliances are those which burn fuels for warmth, cooking or decorative purposes. Typical fuels are gas, both natural and liquefied petroleum (LP), kerosene, oil, coal and wood. Examples of the appliances are space heaters, ranges, ovens, stoves, furnaces, fireplaces, water heaters, and clothes dryers. These appliances are usually safe. However, under certain conditions, these appliances can produce combustion pollutants that can damage your health, or even kill you.
What are Combustion Pollutants?
Combustion pollutants are gases and particles that come from burning materials. The combustion pollutants come from burning fuels in appliances. The types and amounts of pollutants produced depend on the type of appliance, how well the appliance is installed, maintained and vented, and the kind of fuel it uses. Some of the common pollutants produced from burning these fuels are carbon monoxide, nitrogen dioxide, particles, and sulfur dioxide. Particles can have hazardous chemicals attached to them. Other pollutants that can be produced by some appliances are unburned hydrocarbons and aldehydes. Combustion always produces water vapor. Water vapor is not usually considered a pollutant, but it can act as one. It can result in high humidity and wet surfaces.
Where do Combustion Pollutants Come From?
Combustion pollutants found indoors include outdoor air, tobacco smoke, exhaust from car and lawn mower internal combustion engines, and some hobby activities, such as welding, woodburning and soldering. Combustion pollutants can also come from vented or unvented combustion appliances. These appliances include space heaters, gas ranges and ovens, furnaces, gas water heaters, gas clothes dryers, wood and coal-burning stoves, and fireplaces. As a group, these are called “combustion appliances.”
Vented appliances are appliances designed to be used with a duct, chimney, pipe, or other device that carries the combustion pollutants outside the home. These appliances can release large amounts of pollutants directly into your home if a vent is not properly installed, or is blocked or leaking. Unvented appliances do not vent to the outside, so they release combustion pollutants directly into the home. Many of these problems are hard for a homeowner to identify. A professional is needed.
What are the Health Effects of Combustion Pollutants?
The health effects of combustion pollutants range from headaches and breathing difficulties to death. The health effects may show up immediately after exposure, or occur after being exposed to the pollutants for a long time. The effects depend on the type and amount of pollutants, and the length of time of exposure to them. They also depend upon several factors related to the exposed person. These include the age and any existing health problems. There are still some questions about the level of pollutants or the period of exposure needed to produce specific health effects. Further studies to better define the release of pollutants from combustion appliances and their health effects are needed.
The sections below discuss health problems associated with some common combustion pollutants. These pollutants include carbon monoxide, nitrogen dioxide, particles, and sulfur dioxide. Even if you are healthy, high levels of carbon monoxide can kill you within a short time. The health effects of the other pollutants are generally more subtle and are more likely to affect susceptible people. It is always a good idea to reduce exposure to combustion pollutants by using and maintaining combustion appliances properly.
Each year, according to CPSC, there are more than 200 carbon monoxide deaths related to the use of all types of combustion appliances in the home. Exposure to carbon monoxide reduces the blood’s ability to carry oxygen. Often, a person or an entire family may not recognize that carbon monoxide is poisoning them. The chemical is odorless, and some of the symptoms are similar to common illnesses. This is particularly dangerous because carbon monoxide’s deadly effects will not be recognized until it is too late to take action against them. Carbon monoxide exposures especially affect unborn babies, infants, and people with anemia or a history of heart disease. Breathing low levels of the chemical can cause fatigue and increase chest pain in people with chronic heart disease. Breathing higher levels of carbon monoxide causes symptoms such as headaches, dizziness, and weakness in healthy people. Carbon monoxide also causes sleepiness, nausea, vomiting, confusion and disorientation. At very high levels, it causes loss of consciousness and death.
Breathing high levels of nitrogen dioxide causes irritation of the respiratory tract and causes shortness of breath. Compared to healthy people, children, and individuals with respiratory illnesses such as asthma, may be more susceptible to the effects of nitrogen dioxide. Some studies have shown that children may have more colds and flu when exposed to low levels of nitrogen dioxide. When people with asthma inhale low levels of nitrogen dioxide while exercising, their lung airways can narrow and react more to inhaled materials.
Particles suspended in the air can cause eye, nose, throat and lung irritation. They can increase respiratory symptoms, especially in people with chronic lung disease or heart problems. Certain chemicals attached to particles may cause lung cancer, if they are inhaled. The risk of lung cancer increases with the amount and length of exposure. The health effects from inhaling particles depend upon many factors, including the size of the particle and its chemical make-up.
Sulfur dioxide at low levels of exposure can cause eye, nose, and respiratory tract irritation. At high exposure levels, it causes the lung airways to narrow. This causes wheezing, chest tightness, and breathing problems. People with asthma are particularly susceptible to the effects of sulfur dioxide. They may have symptoms at levels that are much lower than the rest of the population.
Combustion may release other pollutants. They include unburned hydrocarbons and aldehydes. Little is known about the levels of these pollutants in indoor air and the resulting health effects.
What do I do if I suspect that combustion pollutants are affecting my health?
If you suspect you are being subjected to carbon monoxide poisoning, get fresh air immediately. Open windows and doors for more ventilation, turn off any combustion appliances, and leave the house. You could lose consciousness and die from carbon monoxide poisoning if you do nothing. It is also important to contact a doctor immediately for a proper diagnosis. Remember to tell your doctor that you suspect carbon monoxide poisoning is causing your problems. Prompt medical attention is important. Some symptoms from combustion pollutants — including headaches, dizziness, sleepiness, coughing, and watery eyes — may also occur because of common medical problems. These medical problems include colds, the flu, and allergies. Similar symptoms may also occur because of other indoor air pollutants. Contact your doctor for a proper diagnosis.
How can I reduce my exposure to combustion pollutants?
Proper selection, installation, inspection and maintenance of your appliances are extremely important in reducing your exposure to these pollutants. Providing good ventilation in your home and correctly using your appliance can also reduce your exposure to these pollutants. Additionally, there are several different residential carbon monoxide detectors for sale. These detectors alert consumers to harmful carbon monoxide levels in the home. They may soon be widely available to reduce deaths from carbon monoxide poisoning.
- Choose vented appliances whenever possible.
- Buy only combustion appliances that have been tested and certified to meet current safety standards. Examples of certifying organizations are Underwriters Laboratories (UL) and the American Gas Association (AGA) Laboratories. Look for a label that clearly shows the certification.
- All currently manufactured vented gas heaters are required by industry safety standards to have a safety shut-off device. This device helps protect you from carbon monoxide poisoning by shutting off an improperly vented heater.
- Check your local and state building codes and fire ordinances to see if you can use an unvented space heater, if you are considering purchasing one. They are not allowed to be used in some communities, dwellings, and certain rooms in the house.
- If you must replace an unvented gas space heater with another, make it a new one. Heaters made after 1982 have a pilot light safety system called an oxygen depletion sensor (ODS). This system shuts off the heater when there is not enough fresh air, before the heater begins producing large amounts of carbon monoxide. Look for the label that tells you that the appliance has this safety system. Older heaters will not have this protection system.
- Consider buying gas appliances that have electronic ignitions rather than pilot lights. These appliances are usually more energy-efficient and eliminate the continuous low-level pollutants from pilot lights.
- Buy appliances that are the correct size for the area you want to heat. Using the wrong size heater may produce more pollutants in your home and is not an efficient use of energy.
- All new wood stoves are EPA-certified to limit the amounts of pollutants released into the outdoor air. For more information on selecting, installing, operating, and maintaining wood-burning stoves, write to the EPA Wood Heater Program. Before buying a wood stove, check your local laws about the installation and use of wood stoves.
To reduce indoor air pollution, a good supply of fresh, outdoor air is needed. The movement of air into and out of your home is very important. Normally, air comes in through cracks around doors and windows. This air helps reduce the level of pollutants indoors. This supply of fresh air is also important to help carry pollutants up the chimney, stovepipe or flue to the outside.
- Keep doors open to the rest of the house from the room where you are using an unvented gas space heater or kerosene heater, and crack open a window. This allows enough air for proper combustion, and reduces the level of pollutants, especially carbon monoxide.
- Use a hood fan if you are using a range. They reduce the level of pollutants you breathe if they exhaust to the outside. Make sure that enough air is coming into the house when you use an exhaust fan. If needed, open a door or window slightly, especially if other appliances are in use. For proper operation of most combustion appliances and their venting systems, the air pressure in the house should be greater than that outside. If not, the vented appliances could release combustion pollutants into the house rather than outdoors. If you suspect that you have this problem, you may need the help of a qualified person to solve it.
- Make sure that your vented appliance has the vent connected and that nothing is blocking it. Make sure there are no holes or cracks in the vent. Do not vent gas clothes dryers or water heaters into the house for heating. This is unsafe.
- Open the stove’s damper when adding wood. This allows more air into the stove. More air helps the wood burn properly, and prevents pollutants from being drawn back into the house instead of going up the chimney. If there is isible smoke or a constant smoky odor inside the home while using a wood-burning stove, this is a sign that the stove is not working properly. Soot on furniture in the rooms where you are using the stove also tells this. Smoke and soot are signs that the stove is releasing pollutants into the indoor air.
Correct Use of Appliances
- Read and follow the instructions for all appliances so that you understand how they work. Keep the owner’s manual in a convenient place to refer to when needed. Also, read and follow the warning labels because they tell you important safety information that you need to know. Reading and following the instructions and warning labels could save your life.
- Always use the correct fuel for the appliance.
- Use only water-clear ASTM 1-K kerosene for kerosene heaters. The use of kerosene other than 1-K could lead to a release of more pollutants in your home. Never use gasoline in a kerosene heater because it can cause a fire or an explosion. Using even small amounts of gasoline could cause a fire.
- Use seasoned hardwoods (elm, maple, oak) instead of softwoods (cedar, fir, pine) in wood-burning stoves and fireplaces. Hardwoods are better because they burn hotter and form less creosote, an oily, black tar that sticks to chimneys and stove pipes. Do not use green or wet woods as the primary wood because they make more creosote and smoke. Never burn painted scrap wood or wood treated with preservatives, because they could release highly toxic pollutants, such as arsenic or lead. Plastics, charcoal, and colored paper, such as comics and wrapping paper, also produce pollutants. Never burn anything that the stove or fireplace manufacturer does not recommend.
- Never use a range, oven or dryer to heat your home. When you misuse gas appliances in this way, they can produce fatal amounts of carbon monoxide. They can produce high levels of nitrogen dioxide, too.
- Never use an unvented combustion heater overnight or in a room where you are sleeping. Carbon monoxide from combustion heaters can reach dangerous levels.
- Never ignore a safety device when it shuts off an appliance. It means that something is wrong. Read your appliance instructions to find out what you should do, or have a professional check out the problem.
- Never ignore the smell of fuel. This usually indicates that the appliance is not operating properly or is leaking fuel. Leaking fuel will not always be detectable by smell. If you suspect that you have a fuel leak, have it fixed as soon as possible. In most cases, you should shut off the appliance, extinguish any other flames or pilot lights, shut off other appliances in the area, open windows and doors, call for help, and leave the area.
Inspection and Maintenance
Have your combustion appliance regularly inspected and maintained to reduce your exposure to pollutants. Appliances that are not working properly can release harmful and even fatal amounts of pollutants, especially carbon monoxide. Have chimneys and vents inspected when installing or changing vented heating appliances. Some modifications may be required. For example, if a change was made in your heating system from oil to natural gas, the flue gas produced by the gas system could be hot enough to melt accumulated oil-combustion debris in the chimney or vent. This debris could block the vent, forcing pollutants into the house. It is important to clean your chimney and vents, especially when changing heating systems. Always hire an InterNACHI inspector to perform your home inspections, as they all must pass the most comprehensive, rigorous training program available.
What are the Inspection and Maintenance Procedures?
The best advice is to follow the recommendations of the manufacturer. The same combustion appliance may have different inspection and maintenance requirements, depending on where you live. In general, check the flame in the furnace combustion chamber at the beginning of the heating season. Natural gas furnaces should have a blue flame with perhaps only a slight yellow tip. Call your appliance service representative to adjust the burner if there is a lot of yellow in the flame, or call your local utility company for this service. LP units should have a flame with a bright blue center that may have a light yellow tip. Pilot lights on gas water heaters and gas cooking appliances should also have a blue flame. Have a trained service representative adjust the pilot light if it is yellow or orange. Before each heating season, have flues and chimneys inspected before each heating season for leakage and for blockage by creosote or debris. Creosote buildup or leakage could cause black stains on the outside of the chimney or flue. These stains can mean that pollutants are leaking into the house.
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