Health Impacts of Combustion in Homes

Literature Review on the Impacts of Residential Combustion

This report explores the health and environmental impacts of indoor residential combustion, which includes methane gas appliances, woodburning stoves and fireplaces.

Two thirds of U.S. households burn fuel in their homes. These households burn methane (also called natural gas), wood, propane, heating oil or other fuel to heat their homes and water, dry their clothes and cook their food. Burning fuel produces emissions that are harmful to human health and the environment. Some types of appliances, including cook stoves, release their emissions directly into the home, where they are inhaled by residents. Other appliances such as furnaces and water heaters, when installed and operated as designed, vent most combustion by-products to the outside, where they contribute to air pollution and climate change.  

What's Burning? Residential Fuel Use in the U.S.

Of the approximately 118.2 million housing units in the United States, nearly all have access to and use electricity. Two-thirds of homes also use one or more sources of combustion: roughly 60% of residences use gas, 15% of homes use other fossil fuels including propane, fuel oil and kerosene, and 9% of homes use wood. 

2/3 of homes use combustion sources
60% use gas
15% use propane, fuel oil and kerosene
9% use wood

The primary pollutants emitted by combustion appliances include, but are not limited to: 

A dangerous gas that when inhaled can interfere with the ability of blood to carry oxygen from the lungs to the rest of the body.

A respiratory irritant that causes airway inflammation, coughing, wheezing and increased asthma attacks.

A mixture of microscopic solids and liquids that impacts multiple body systems and can increase the risk of premature death.

including as ammonia, formaldehyde, polycyclic aromatic hydrocarbons (PAHs) and volatile organific compounds (VOCs) that can cause cancer, birth defects and other serious health harms.

What Are Combustion Appliances?

  • Furnaces 
  • Stoves/Cooktops/Ovens 
  • Water Heaters 
  • Clothes Dryers 
  • Wood Stoves and Fireplaces

Key Findings

Worsening Asthma Symptoms 

Appliances using combustion to create energy can increase asthma symptoms in children and other vulnerable populations. Studies show consistent associations between higher pollution levels and detrimental respiratory effects in children from exposure to pollutants, including worse lung function for children with asthma.   

Indoor exposure to gas cooking can worsen asthma symptoms, wheezing, and result in reduced lung function in children, particularly in the absence of ventilation and for children living with asthma or allergies.   

Increased Particle Pollution

Wood-burning heating appliances create sharp increases in indoor levels of particle pollution.  

Dangers to health resulting from exposure to wood burning are well-established. Emissions in wood smoke can cause coughing, wheezing, asthma attacks, heart attacks, lung cancer, and premature death, among other health effects.  

Indoor wood burning is responsible for up to 90% of local particulate matter pollution in smaller communities and rural areas. 

woodburning fire in home fireplace

Climate Change

Household use of gas, wood, propane and heating oil drives climate change through the emission of compounds such as carbon monoxide, nitrogen oxides, particulate matter, formaldehyde and others. 

What Can Be Done?

To protect individuals and communities from the health impacts of pollution from indoor combustion, the American Lung Association recommends a three-pronged approach: personal protection, source reduction and additional research.

If you rely on combustion appliances for heating, hot water and/or cooking, there are some immediate steps you can take to reduce your risk from exposure to harmful pollutants:

  • Make sure your gas appliances are in proper working order.  
  • Install carbon monoxide monitors. 
  • Use ventilation, either a range hood that vents to the outside or an open window or both.
  • For homes that rely on wood burning for heat or cooking, an air cleaning device that uses HEPA filtration can provide some protection from the soot and smoke.

Individuals and communities can take steps to reduce the emission of combustion pollutants to protect public health:

  • Individuals can reduce or eliminate the use of unnecessary wood burning and replace gas appliances with electric as circumstances allow. 
  • Homeowners can take advantage of incentives programs available from utilities and government programs to purchase cleaner and more efficient heating systems, water heaters, clothes dryers, and stoves.
  • Public and private entities, including schools, employers and building owners and managers, should assess the impact of combustion pollutants on indoor air quality in their facilities and take steps to reduce or eliminate them.
  • Appliance manufacturers and regulators should increase appliance efficiency and safety standards, including setting zero-emission appliance standards.

To develop effective policies and practices to reduce the health harms from combustion pollutants indoors, more research is needed on all aspects of the issue to: 

  • Better quantify the number and use of combustion appliances in the U.S. 
  • Measure the impact of all types of combustion pollutants on the indoor environment in all types of residences. 
  • Study the health effects of combustion pollutants in “real world settings” in the U.S., with an emphasis on sensitive populations.
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