Air Pollution: Invading Your Indoor Space?

Indoor air pollution is a serious threat to human health, causing millions of deaths each year. The air within homes and other buildings can be more seriously polluted than the outdoor air in even the most industrialized cities. This is concerning as people spend approximately 90% of their time indoors.

Indoor air pollution is caused by a variety of sources, including combustion sources such as building materials, furnishings, household products, central heating and cooling systems, and outdoor sources such as radon, pesticides, and outdoor air pollution. Inadequate ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions and by not carrying indoor air pollutants out of the home. High temperature and humidity levels can also increase concentrations of some pollutants.

Health effects from indoor air pollutants may be experienced soon after exposure or years later. Immediate effects include irritation of the eyes, nose and throat, headaches, dizziness, and fatigue. Other health effects may show up years after exposure or only after long or repeated periods of exposure, including respiratory diseases, heart disease, and cancer.

To improve indoor air quality, it is important to eliminate individual sources of pollution, increase ventilation, and install air cleaning devices.

Building and Paint Products

New Building Materials

Building materials, such as plywood, furniture, and other pressed-wood products, often contain chemicals that give off gases and odors as they age. These products can release formaldehyde and other volatile organic compounds (VOCs) into the indoor air. Using multiple products simultaneously may mix several different chemical fumes in the same indoor space.

Paints, adhesives, solvents, polishes, carpeting, and cleaning products can also emit VOCs, formaldehyde, benzene, and other toxic chemicals over time. It is important to note that "Chinese drywall," installed in some buildings along the Gulf Coast states and Virginia between 2001 and 2009, has been associated with health issues such as coughing, shortness of breath, nausea, headaches, and fatigue. Investigations revealed that this drywall gave off high levels of indoor hydrogen sulfide.

Older Building Materials

Older building products, like tiles, insulation, or drywall, may contain asbestos. Homes constructed before 1978 are likely to have lead paint. Removing or demolishing these materials can release hazardous chemicals into the air or dust. Plasticizers found in some flooring, pipes, and other materials have been linked to various health issues.

Protecting Your Indoor Air Quality

To safeguard your indoor air quality, consider the following:

• Choose building materials and paint with low or no emissions.
• Discuss with your contractor or building material provider to ensure you obtain products with minimal emissions.
• Request that building materials and carpets be ventilated for at least 72 hours before installation.
• Maintain good ventilation during and after using these products, following the manufacturer's ventilation recommendations.
• Only purchase what is necessary for your project, and avoid leaving open containers of unused paint or paint thinners indoors.
• Exercise caution when remodelling or demolishing older homes with potential lead paint or asbestos. If possible, avoid disturbing these materials. If disturbance is necessary, follow guidelines from the U.S. Environmental Protection Agency or seek professional assistance.

Cleaning Supplies and Household Chemicals

Cleaning and maintaining indoor spaces is essential for healthy living. However, cleaning supplies and household chemicals can negatively impact indoor air quality and, subsequently, our health.

Volatile organic compounds (VOCs) are chemicals that vaporize at room temperature and are commonly found in household cleaning and maintenance products. These include detergents, cleaning compounds, polishes, floor finishes, disinfectants, and sanitizers. VOCs are released into the air and can cause indoor air pollution, which may be two to five times higher than outdoor air pollution.

The health effects of exposure to VOCs and other chemicals in cleaning products include irritation of the eyes, nose, and throat, as well as headaches, dizziness, and fatigue. More severe consequences can be respiratory diseases, heart disease, and cancer. Formaldehyde, for example, is a known human carcinogen with no safe level of exposure. It is a strong eye, nose, throat, and lung irritant.

Additionally, cleaning products can contain toxic air contaminants (TACs) and greenhouse gases (GHGs). These chemicals can be harmful through direct exposure or by reacting with other chemicals in the air to form dangerous by-products. For instance, terpenes, found in pine and citrus oils, can react with ozone to produce formaldehyde and ultrafine particles, which are harmful to human health.

It is important to note that even products advertised as "green" or "natural" may still contain harmful ingredients. Consumers should be cautious and research the products they use. Reading labels, choosing products with reduced or no VOCs, fragrances, irritants, and flammable ingredients, and ensuring proper ventilation during and after cleaning are essential steps to reduce exposure to harmful chemicals.

By being mindful of the potential risks associated with cleaning supplies and household chemicals, individuals can take the necessary precautions to protect their health and improve indoor air quality.

Residential Wood Burning

Wood smoke is a significant contributor to particle pollution, particularly in rural and tribal communities that rely on wood-burning stoves for warmth and cooking. These communities are at an increased risk of exposure to harmful emissions, including carbon monoxide, nitrogen oxides, and volatile organic compounds (VOCs). Carbon monoxide is a poisonous gas that can cause illness and even death in severe cases. Nitrogen oxides contribute to both indoor and outdoor particle pollution, while VOCs are harmful pollutants that contribute to the creation of ozone pollution. Some VOCs, such as benzene and formaldehyde, are known carcinogens.

The use of wood-burning stoves and fireplaces can also impact the indoor air quality of neighbouring homes. It is recommended that individuals avoid using wood-burning stoves or fireplaces unless they are a primary heat source. If wood-burning is the only option, it is important to follow safe burning practices, such as using a modern, EPA-certified wood-burning stove, burning only seasoned firewood, and ensuring proper ventilation. Maintaining the fireplace or wood stove and regularly removing ashes are also important steps in reducing emissions.

In addition to the health risks, wood burning also has financial and environmental implications. It is often more expensive than other forms of heating, and it contributes to climate change by releasing carbon dioxide and methane, two significant greenhouse gases. Despite the perception that burning wood is a greener alternative, it actually releases more carbon dioxide than oil or gas for the same amount of heat or energy.

To protect yourself and others from the harmful effects of wood-burning emissions, it is important to consider alternative heat sources. If wood burning is the only option, it is crucial to burn dry, "Ready to Burn" certified fuel in a modern, EPA-certified stove. Burning dry wood reduces the amount of pollutants produced compared to burning wet wood. It is also important to never burn painted or preserved wood, as this will create more air pollution.

Volatile Organic Compounds

The US Environmental Protection Agency's Total Exposure Assessment Methodology (TEAM) Study found levels of about a dozen common organic pollutants to be 2 to 5 times higher inside homes than outside, regardless of location. The study also indicated that people can expose themselves and others to very high pollutant levels during product use, and elevated concentrations can remain in the air long after use.

Health effects of VOC exposure include eye, nose, and throat irritation, headaches, nausea, dizziness, and difficulty breathing. Long-term exposure can lead to liver, kidney, and central nervous system damage, and some VOCs are linked to cancer. People with asthma or COPD may experience worsened symptoms.

To reduce exposure to VOCs, it is recommended to increase ventilation, read product labels, avoid or limit the use of harmful products, safely dispose of unwanted items, and opt for low-VOC alternatives.

Scents and Chemicals

The use of air fresheners is associated with elevated levels of volatile organic compounds (VOCs) in indoor air. VOCs are often difficult to smell but can irritate the eyes, nose, and throat, as well as cause headaches and nausea. The types and amounts of VOCs emitted depend primarily on the fragrance composition of the air freshener, not on the type of air freshener.

Air fresheners can add VOCs and other pollutants to the air through direct emissions from fresheners as well as through secondary reaction products from the freshener chemicals reacting with constituents (such as ozone) that are already in the air. For example, air freshener emissions can react with naturally-occurring indoor air compounds, such as ozone, to produce secondary pollutants such as formaldehyde.

The use of air fresheners can increase exposure levels to air pollutants. These exposures, even at relatively low levels, have been associated with a range of adverse health effects. These effects may include migraine headaches, asthma attacks, breathing and respiratory difficulties, dermatitis, and neurological problems, particularly for sensitive individuals.

Some air freshener products are described as “green” or “organic”, but these terms lack regulatory or chemical definitions when used with air fresheners. Studies comparing emissions of different types of air fresheners have found that all air fresheners – regardless of “green” claims – emit potentially hazardous compounds. Moreover, emissions from “green” air fresheners were not found to be significantly different from other fresheners.

Homemade or “natural” air fresheners made with essential oils are not necessarily free of potentially harmful chemicals, either. Essential oils consist of combinations of naturally-derived chemicals that are highly concentrated. Concentrations of these oils in nature are typically much lower than the concentrations found in essential oils. Moreover, few of these oils and plant-based ingredients have been tested for safety, and some can trigger allergic reactions.

Some air fresheners purportedly clean the air by removing odors, disinfecting the air, or reducing allergens. These claims have been difficult to scientifically verify. Moreover, the use of these products would not provide a long-term solution since the source of odors, bacteria, or other allergens would not be addressed.

Ways to mitigate undesirable odors in an indoor air environment without the use of air fresheners include:

• Removing the source of the odor
• Increasing ventilation by opening a window or using an exhaust fan
• Improving and increasing ventilation by maintaining HVAC systems
• Regular cleaning and vacuuming
• Use of an air purifier when other means are not sufficient

Frequently asked questions