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.
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.
Correct Use of Appliances
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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International Association of Certified Indoor Air Consultants