Air Quality Focus: Indoors Vs High Pollution

Air quality is a significant issue for human health and well-being, with indoor air pollution being a global concern. Spending time indoors, especially for susceptible groups such as children, the elderly, and those with pre-existing conditions, can lead to exposure to pollutants with adverse health effects. During periods of high outdoor pollution, indoor air quality becomes even more critical as outdoor pollutants can infiltrate indoor spaces through doors, windows, ventilation systems, and structural cracks. Inadequate ventilation exacerbates the problem by not effectively diluting indoor emissions or removing pollutants. This results in a build-up of harmful substances, including carbon monoxide, particulate matter, and volatile organic compounds from various sources. The impact of indoor air pollution on health can vary depending on individual sensitivity, with some people experiencing immediate reactions similar to cold or viral disease symptoms. Understanding and improving indoor air quality during high outdoor pollution are essential to mitigate potential health risks and create healthier indoor environments.

Indoor air pollution sources

Indoor air pollution is mainly caused by indoor sources that release gases or particles into the air. The air within buildings can contain pollutants in concentrations 2 to 5 times higher than typical outdoor concentrations. Inadequate ventilation can increase indoor pollutant levels by not bringing in enough outdoor air to dilute emissions from indoor sources and by not carrying indoor air pollutants out of the area. High temperature and humidity levels can also increase concentrations of some pollutants.

There are many sources of indoor air pollution. Outdoor air pollutants can enter buildings through open doors, windows, ventilation systems, and cracks in structures. For example, harmful smoke from chimneys can re-enter homes and pollute the air. Some pollutants come indoors through building foundations. For instance, radon forms in the ground as uranium in rocks and soils decays and can enter buildings through cracks. In areas with contaminated ground water or soils, volatile chemicals can enter buildings through the same process. Volatile chemicals in water supplies can also enter indoor air when building occupants use the water. People can also bring in outdoor pollutants on their shoes and clothing.

Combustion sources in indoor settings, including tobacco, wood and coal heating and cooking appliances, and fireplaces, can release harmful combustion byproducts such as carbon monoxide directly into the indoor environment. An improperly adjusted gas stove can emit significantly more carbon monoxide than one that is properly adjusted. Building materials are also potential sources, whether through degrading materials (e.g. asbestos fibers released from building insulation) or from new materials (e.g. chemical off-gassing from pressed wood products).

Some sources, such as building materials, furnishings, and products like air fresheners, can release pollutants more or less continuously. Other sources, related to activities like smoking, cleaning, redecorating, or hobbies, release pollutants intermittently. Unvented or malfunctioning appliances or improperly used products can release higher and sometimes dangerous levels of pollutants indoors.

Inadequate ventilation

Poor ventilation can lead to a build-up of indoor air pollutants, which can be a significant issue during periods of high outdoor air pollution. When ventilation is inadequate, indoor air can become stagnant, with pollutants accumulating and reaching levels that are harmful to human health.

Indoor air quality can be impacted by a range of pollutants, including volatile organic compounds (VOCs), particulate matter, carbon monoxide, and radon. These pollutants can come from a variety of sources, such as building materials, furniture, cleaning products, cooking, and smoking. Inadequate ventilation can cause these pollutants to become trapped indoors, leading to a range of health issues for occupants.

One of the key risks associated with inadequate ventilation is the potential for high levels of particulate matter and VOCs to be present in the indoor air. These pollutants can come from outdoor sources, such as traffic and industrial emissions, and can enter buildings through openings. They can also be generated indoors through activities. When ventilation is poor, these pollutants can accumulate, leading to a range of health issues.

Another concern during periods of high outdoor air pollution is the potential for indoor carbon monoxide levels to rise. Carbon monoxide is a toxic gas that can be produced by fuel-burning appliances. Inadequate ventilation can cause carbon monoxide to build up indoors, leading to serious health risks.

To mitigate the risks associated with inadequate ventilation during high outdoor air pollution, it is important to improve indoor air quality. This may include increasing outdoor air circulation, using air purification systems, and ensuring that fuel-burning appliances are properly ventilated and maintained. It is also important to minimize the use of products that contribute to indoor air pollution.

Outdoor air quality impact

Outdoor air quality has a significant impact on indoor air quality. Poor outdoor air quality can lead to an increase in indoor pollutant levels, especially in buildings with inadequate ventilation. Mechanical ventilation systems in large buildings are designed to draw in and circulate outdoor air, but they may not always be effective in improving indoor air quality. Poor outdoor air quality can also have direct health impacts on individuals who spend a significant amount of time outdoors, such as those who work outside.

Outdoor air pollution contains numerous substances of both natural and anthropogenic (human-caused) origin. Natural sources of outdoor air pollution include pollen, mold spores, and dust, while anthropogenic sources are of particular interest as they can be reduced through regulatory and voluntary actions. Examples of anthropogenic sources include emissions from oil refineries, chemical production facilities, and vehicles.

The impact of outdoor air quality on human health is significant. According to the World Health Organization (WHO), outdoor air pollution is a major environmental health problem affecting individuals in low-, middle-, and high-income countries. In 2019, WHO estimated that 4.2 million premature deaths worldwide were caused by outdoor air pollution, with 89% of those occurring in low- and middle-income countries. Long-term exposure to outdoor air pollution has been linked to various health issues, including asthma, respiratory tract infections, heart disease, cognitive deficits, and cancer.

Certain populations are more vulnerable to the effects of outdoor air pollution. People who live or work near major sources of pollution, such as highways, busy roads, or industrial operations, are at a higher risk of exposure. Additionally, low-income communities, people of color, and individuals with pre-existing health conditions are disproportionately affected by air pollution due to factors such as limited mobility options, socioeconomic status, and higher rates of chronic conditions.

Improving outdoor air quality requires coordinated efforts and policies that address key sources of pollution. This includes promoting cleaner transport, energy-efficient practices, improved waste management, and access to clean household energy. By addressing these issues, public health outcomes can be significantly improved, reducing the number of premature deaths and illnesses associated with poor outdoor air quality.

Health effects

Poor air quality during high pollution can have a range of adverse health effects. Indoor air pollution is a significant issue, with concentrations of some pollutants being two to five times higher indoors than outdoors. People spend a lot of time indoors, and those most susceptible to the effects of pollution tend to spend even more time inside.

Some health effects can show up shortly after exposure to indoor air pollutants, including irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. These immediate effects are usually short-term and treatable, and symptoms often disappear when a person is removed from the polluted environment. However, for people with asthma or chronic obstructive pulmonary disease (COPD), air pollution can trigger asthma attacks, cause wheezing, and make it harder to breathe.

Long-term exposure to indoor air pollution has been linked to more severe health issues, including respiratory diseases, heart disease, cognitive deficits, and cancer. Indoor air pollution has also been associated with 6.7 million premature deaths annually worldwide. Certain populations are more vulnerable to the adverse health impacts of indoor air pollution, including children, older adults, individuals with pre-existing conditions, and low-income communities.

Indoor air pollution sources that release gases or particles into the air are the primary cause of poor indoor air quality. Inadequate ventilation, high temperatures, and humidity levels can increase indoor pollutant levels. Building materials, furnishings, cleaning products, and personal care products can all contribute to indoor air pollution. Biological pollutants such as mold, pollen, animal dander, and dust mites are common triggers for allergic symptoms and breathing problems.

It is important to note that the scientific understanding of indoor air quality and its health effects is still evolving. However, the potential impact of indoor air quality on human health is significant, and it is prudent to take steps to improve the indoor air quality in homes, schools, and offices.

Preventing indoor air problems

Understand the sources of indoor air pollution:

Recognize the potential sources of indoor air pollution to effectively prevent and control them. Indoor air pollution can arise from various sources, including combustion sources such as tobacco smoke, wood or coal-burning appliances, and fireplaces, which can release harmful byproducts like carbon monoxide. Other sources include cleaning supplies, paints, insecticides, and building materials such as asbestos or pressed wood products that emit chemicals. Even activities like cooking, painting, welding, or using cleaning products can generate high levels of pollutants.

Improve ventilation:

Ventilation is crucial for maintaining good indoor air quality. Increase the amount of outdoor air coming indoors by opening windows and doors when the weather permits. Utilize window or attic fans, and run air conditioners with the vent control open to enhance the outdoor ventilation rate. Exhaust fans in bathrooms and kitchens are particularly effective at removing contaminants directly from those rooms while also increasing overall ventilation. Advanced designs for new homes may also include mechanical systems, such as energy-efficient heat recovery ventilators, that bring in fresh outdoor air and help control indoor temperatures.

Control individual sources of pollution:

Eliminate or reduce emissions from specific sources of pollution. For example, seal or enclose materials containing asbestos, and adjust gas stoves to decrease emissions. When performing activities that generate high levels of pollutants, such as painting or cooking, ensure proper ventilation and consider using alternative methods or products that produce fewer emissions.

Maintain a clean and dust-free environment:

Regular cleaning and dusting can help minimize the presence of allergens and biological contaminants. Use a central vacuum system vented to the outdoors or a vacuum with a high-efficiency filter. Wash bedding and other washable items in hot water (around 130 degrees Fahrenheit) to reduce allergens. Avoid furnishings that accumulate dust, especially those that cannot be washed easily.

Monitor your health and the indoor environment:

Pay attention to any symptoms you experience, such as eye irritation, nose or throat irritation, headaches, dizziness, or fatigue, as they may be indicators of indoor air pollution exposure. Take note of when and where these symptoms occur, and if they disappear when you're away from a particular area. This information can help identify potential indoor air pollution sources and take appropriate action.

Remember, while these strategies provide guidance on preventing indoor air problems, the effectiveness may vary depending on specific circumstances and individual sensitivity to pollutants.

Frequently asked questions