Air Pollution Indoors: A Dangerous, Invisible Threat

Indoor air pollution is a global issue that can have serious health consequences. It refers to the quality of the air in a home, school, office, or other building environments. A high level of indoor air pollution is caused by the release of harmful pollutants, such as fine particulate matter, carbon monoxide, and various other toxins, inside buildings. These pollutants can come from sources inside buildings, such as combustion sources, tobacco smoke, cleaning products, paints, and building materials, or they can enter buildings from outdoor sources through open doors, windows, ventilation systems, or cracks in structures. Inadequate ventilation and high temperature and humidity levels can also contribute to high indoor pollutant levels. High levels of indoor air pollution have been linked to respiratory infections, asthma, heart disease, cognitive deficits, and cancer. Certain populations, such as children, older adults, and individuals with pre-existing conditions, may be more susceptible to the adverse effects of indoor air pollution.

Indoor air pollution sources

Indoor air pollution is a pressing issue that can have detrimental effects on human health. The sources of indoor air pollution are diverse and varied, and it is crucial to be aware of them to mitigate potential health risks. Here are some of the key sources of indoor air pollution:

Inadequate Ventilation: Poor ventilation is a significant contributor to indoor air pollution. Inadequate ventilation allows pollutants to accumulate, leading to high pollutant concentrations. This is particularly common in buildings designed to minimize the flow of outdoor air, such as those with mechanical ventilation systems. Natural ventilation through openings like windows and doors is essential, but it may not always be sufficient to maintain good air quality.

Outdoor Air Pollution: Outdoor pollutants can infiltrate indoor spaces and contribute to indoor air pollution. The impact of outdoor pollution sources depends on the amount of pollution emitted and the hazardous nature of those emissions. For example, an improperly adjusted gas stove can emit high levels of carbon monoxide. Additionally, outdoor pollution can enter indoor spaces through infiltration, natural ventilation, or mechanical ventilation systems.

Human Activities: Certain human activities within buildings can generate indoor air pollution. These activities include smoking, burning solid fuels, cooking with polluting devices like wood stoves or open fires, and cleaning with certain products. The use of unvented or malfunctioning appliances, as well as improper product usage, can release dangerous levels of pollutants.

Building Materials and Furnishings: Construction materials, home improvement products, and textiles used in homes can be sources of indoor air pollution. Some building materials may support the growth of biological pollutants like mould and mildew, which release toxic substances. Additionally, certain materials, furnishings, and products like air fresheners can continuously release pollutants into the indoor environment.

Biological Pollutants: Indoor biological pollutants can come from plants, people, and animals. Contaminated central air handling systems can become breeding grounds for certain types of asthma-causing substances and infectious illnesses like influenza, measles, and chickenpox. Mould and mildew growth can also release disease-causing toxins, impacting respiratory health.

Radon Gas: Radon, a colorless, odorless, and radioactive gas, is another indoor air pollutant. It is often associated with uranium in the soil or rock on which homes are built. As uranium breaks down naturally, it releases radon gas, which can enter homes through various pathways.

The awareness of these indoor air pollution sources is essential for taking preventive measures and improving indoor air quality, ultimately reducing potential health risks for occupants.

Health effects of indoor air pollution

Indoor air pollution is a pressing global issue that can have detrimental effects on human health. The concentration of indoor pollutants is often 2 to 5 times higher than typical outdoor levels. This is due to various factors, including inadequate ventilation, inefficient fuel use, and the presence of specific pollutants.

Short-Term Health Effects

Indoor air pollutants can cause immediate adverse effects, including irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. These symptoms may be similar to those of a cold or viral infection, making it challenging to attribute them solely to indoor air pollution. Certain pollutants, such as radon, particle pollution, carbon monoxide, and the Legionella bacterium, are well-established causes of these short-term health issues. For example, elevated carbon monoxide levels in enclosed spaces can be fatal in the short term.

Long-Term Health Effects

Long-term exposure to indoor air pollution can lead to more severe health problems, including respiratory diseases, heart disease, cognitive deficits, and cancer. Children, in particular, are at an elevated risk due to their developing bodies and increased time spent in schools, which often suffer from poor indoor air quality. Additionally, indoor air pollution has been linked to an increased risk of asthma, especially in children, and can trigger asthma attacks in susceptible individuals.

Noncommunicable Diseases

The use of inefficient and polluting fuels and technologies in households contributes to harmful levels of indoor air pollution. This exposure is particularly acute for women and children, who typically spend more time near the domestic hearth. The World Health Organization (WHO) estimates that household air pollution causes approximately 3.2 million deaths per year, with an additional 3.5 million deaths attributed to the combined effects of ambient and household air pollution. These exposures lead to noncommunicable diseases, including stroke, ischaemic heart disease, chronic obstructive pulmonary disease (COPD), and lung cancer.

Reducing Indoor Air Pollution

To mitigate the health impacts of indoor air pollution, it is essential to improve ventilation, minimize the use of polluting fuels and technologies, and address specific sources of pollution, such as building materials, furnishings, and cleaning products. Additionally, organizations like the WHO and the US Environmental Protection Agency (EPA) provide guidelines and recommendations to promote the use of cleaner fuels and technologies, such as solar power, electricity, and liquefied petroleum gas (LPG).

Groups at higher risk

Household air pollution is caused by the use of inefficient and polluting fuels and technologies, which release a range of health-damaging pollutants. These pollutants include small particles that can penetrate deep into the lungs and enter the bloodstream. Indoor air pollution is particularly high in poorly ventilated dwellings, where the levels of fine particles can be up to 100 times higher than acceptable.

While indoor air pollution affects everyone exposed to it, certain groups are at a higher risk of adverse health effects. These include:

Women and Children

Women and children are disproportionately affected by indoor air pollution, especially in low- and middle-income households. They typically spend more time near the domestic hearth, as they are responsible for household chores such as cooking, collecting firewood, and preparing fuel. This prolonged exposure to harmful smoke and inefficient devices increases their health risks. Additionally, the time spent on fuel-related tasks limits their opportunities for education, leisure, and other productive activities.

Individuals with Preexisting Medical Conditions

Those with preexisting medical conditions, such as respiratory diseases, heart disease, or asthma, are more vulnerable to the effects of indoor air pollution. Their health conditions can be exacerbated by exposure to pollutants, and they may experience more severe symptoms or complications.

Older Adults

Older adults are more susceptible to the harmful effects of indoor air pollution due to age-related factors. Their bodies may have weaker defence mechanisms, and they may be more sensitive to pollutants, increasing their risk of respiratory issues and other health problems.

Low Socioeconomic Status Households

Households with low socioeconomic status may face higher indoor air pollution levels due to various factors. This includes living in areas with higher outdoor air pollution, inadequate ventilation in their homes, and limited access to cleaner fuels or technologies. As a result, they experience greater health inequalities and a higher burden of disease.

Native Americans

Research has indicated that Native Americans are often exposed to higher levels of indoor air pollutants. This may be due to a variety of factors, including housing conditions, cultural practices, or geographic locations that contribute to increased exposure to pollutants.

Reducing indoor air pollution

Indoor air pollution is a serious issue, with a wide range of sources contributing to the problem. These sources can be both indoors and outdoors, and the effects of indoor air pollution can be detrimental to human health. Some sources of indoor air pollution include gas appliances, building materials, smoking, cleaning products, and outdoor air pollution.

To reduce indoor air pollution, there are several measures that can be taken:

Ventilation

One of the most effective ways to improve indoor air quality is to increase ventilation. Opening windows and doors can help bring in fresh outdoor air and reduce the concentration of indoor pollutants. Natural ventilation is a simple and cost-effective way to improve air quality and moderate indoor temperature. However, it is important to consider outdoor sources of pollution, such as smoke or refuse, and avoid opening windows and doors if these pollutants are present. Mechanical ventilation systems, such as energy-efficient heat recovery ventilators, can also be installed to bring outdoor air into the home while mitigating the cost of heating or cooling.

Source Control

Identifying and eliminating individual sources of indoor air pollution is crucial. Some sources, like those containing asbestos, should be sealed or enclosed. Other sources, like gas stoves, can be adjusted to decrease emissions. It is important to properly maintain appliances and ensure they are functioning correctly to prevent the release of dangerous levels of pollutants. When purchasing building materials or furnishings, look for labels that indicate low emissions, such as California Phase II Compliant or TSCA Title VI Compliant. Choose cleaning products that are safer for human health and the environment, and minimize the use of strongly scented products, air fresheners, and products containing per- and polyfluoroalkyl substances (PFAS).

Alternative Products and Practices

Using homemade cleaning products, such as a mixture of white vinegar and water, can help reduce the introduction of chemicals into the indoor environment. Store chemicals, solvents, glues, and pesticides away from living areas to minimize their impact on indoor air quality. Avoid using gas stoves or other fuel-burning appliances to heat your home, as this can lead to a dangerous build-up of carbon monoxide and other pollutants. Instead, opt for heating systems that do not rely on indoor combustion. If possible, avoid smoking indoors, as secondhand smoke is a significant respiratory health hazard.

Air Purifiers

While air purifiers alone may not remove all impurities, they can be beneficial in conjunction with other efforts to reduce indoor air pollution. High-efficiency air cleaners that are certified as ozone-free can help reduce airborne particles. Table-top air cleaners may be less effective for strong nearby sources of pollution.

Reduce Moisture and Mold

Indoor mold can contribute to poor air quality and respiratory issues. Using a dehumidifier and regularly cleaning the filter can help reduce moisture and the growth of mold.

By implementing these measures, individuals can effectively reduce their exposure to indoor air pollution and improve their overall health and well-being.

Measuring indoor air pollution

Indoor air pollution is a global issue that can cause a range of health issues, including respiratory diseases, heart disease, cognitive deficits, and cancer. It is important to measure indoor air quality to ensure that the levels of pollutants are within acceptable ranges and to identify any potential health risks associated with high levels of indoor air pollution.

There are several ways to measure indoor air quality, including:

• Using a testing device or monitor: Indoor air quality monitors are devices that use sensors to detect, monitor, and report specific air pollutants and environmental factors such as temperature and humidity. These monitors can be placed indoors to detect pollutants like particulate matter, carbon dioxide, radon, and carbon monoxide. Some monitors have a screen panel that displays the current levels of air pollutants, while others use an app to provide an overview of indoor air quality.
• Hiring an indoor air quality specialist: Specialists can conduct thorough tests to assess indoor air quality. They may use a combination of tests, such as radon and mold tests, to determine the presence and levels of various air pollutants. These specialists can provide accurate assessments and recommendations to improve air quality.
• Measuring CO2 levels: As buildings become more airtight and efficient, carbon dioxide (CO2) levels can build up. Measuring CO2 levels can help determine the staleness of the air. High CO2 levels indicate improper ventilation and the potential presence of other pollutants.
• Community-based research and sensors: Organizations like the National Institute of Environmental Health Sciences (NIEHS) have developed low-cost, portable sensors to detect indoor pollutants. These sensors provide real-time data on indoor air quality and enable community-based research to address daily health risks associated with indoor air pollution.

It is important to note that the accuracy and precision of air quality monitors can vary depending on factors such as placement, time in use, data processing methods, temperature, humidity, and the presence of multiple contaminants. Additionally, different monitors may be more suitable for specific environments, such as older houses or heavily polluted areas, to detect pollutants like carbon monoxide or radon effectively.

Frequently asked questions