Understanding Indoor Air Pollution: Causes And Concerns

Indoor air pollution is caused by a variety of factors, including the use of inefficient and polluting fuels, such as wood, coal, and dung, which are commonly burned indoors in developing countries for cooking and heating purposes. Tobacco smoke is another significant contributor, with secondhand smoke causing approximately 7,300 lung cancer deaths in non-smoking adults in the United States annually. Indoor air pollution can also be caused by inadequate ventilation, allowing indoor pollutant levels to increase and leading to various health issues such as respiratory infections, asthma, and cardiovascular diseases. Other sources of indoor air pollution include cleaning products, mould, pet dander, and construction processes involving paint and carpets. Poor indoor air quality can have detrimental effects on health, causing or contributing to infections, lung cancer, and chronic lung diseases.

Inadequate ventilation

Outdoor air enters and leaves buildings through infiltration, natural ventilation, and mechanical ventilation. Infiltration occurs when outdoor air flows inside through openings, joints, and cracks in walls, floors, and ceilings, as well as around windows and doors. This, along with natural ventilation, is caused by air temperature differences and wind. Inadequate infiltration and natural ventilation can occur due to poor building design or in an effort to make buildings more energy-efficient. Mechanical ventilation devices, such as fans and exhaust systems, can also be insufficient, particularly in the winter when normal activities create more moisture.

To improve indoor air quality, it is important to ensure proper ventilation by increasing the air exchange rate, especially in areas with high levels of pollutants or moisture, such as bathrooms and kitchens. Outdoor-vented fans, spot ventilation, and dilution ventilation can help remove contaminated air and bring in fresh outdoor air. Additionally, regular maintenance and duct sealing can minimise the spread of pollutants through HVAC systems.

Polluting fuels

The World Health Organization (WHO) has recognized the health risks associated with the use of polluting fuels and has issued guidelines for indoor air quality, recommending cleaner alternatives such as solar, electricity, biogas, liquefied petroleum gas (LPG), natural gas, and alcohol fuels. Despite these recommendations, the transition to cleaner fuels and stove combinations remains slow, and many communities lack the capacity to address their environmental health problems effectively.

Indoor air pollution from polluting fuels has severe health consequences. The poor combustion of these fuels releases fine particulate matter and other pollutants, including carbon monoxide, which can cause a range of health issues. Exposure to these pollutants can lead to short-term effects such as burning eyes, coughing, and nose and throat irritation. More seriously, it can cause long-term health problems, including respiratory infections, asthma, heart disease, and lung cancer. The impact is particularly pronounced among women and children, who typically spend the most time near the domestic hearth and bear the greatest health burden.

In addition to the direct health risks, the use of polluting fuels also poses safety risks, especially for children. Kerosene, often sold in refilled soda bottles, is the leading cause of childhood poisonings. Furthermore, the collection and preparation of fuel increase the risk of musculoskeletal damage and injuries from carrying heavy loads, especially in insecure areas.

To address the negative impacts of polluting fuels, it is essential to transition to cleaner alternatives and improve ventilation in indoor spaces. Adequate ventilation can help dilute emissions from indoor sources and reduce pollutant levels, thereby mitigating the health risks associated with indoor air pollution caused by polluting fuels.

Tobacco smoke

The dangers of tobacco smoke are not limited to active smokers but also affect non-smokers exposed to secondhand smoke. In the United States, secondhand smoke is estimated to cause about 7,300 lung cancer deaths among non-smoking adults annually. It is also linked to other health issues such as cardiovascular disease, reproductive problems, and respiratory infections in infants and children. The impact of secondhand smoke is not limited to a single room but can spread throughout a building, including between apartment units. While ventilation, filtration, and air cleaning techniques can reduce indoor secondhand smoke, they do not eliminate it.

In addition to the immediate health effects, tobacco smoke can also have long-term consequences. It has been identified as a risk factor for tuberculosis (TB) infection, disease progression, and mortality. Studies have shown a positive association between tobacco smoking and an increased risk of TB, with smokers having a two-fold higher risk of TB infection compared to non-smokers. Furthermore, the combination of tobacco smoking and indoor air pollution from biomass fuels further exacerbates the risk of TB, especially in developing countries where smoking and the use of biomass fuels are prevalent.

To address the issue of indoor air pollution caused by tobacco smoke, it is essential to implement measures to reduce exposure. This can include creating smoke-free environments, improving ventilation, and raising awareness about the dangers of secondhand smoke. Additionally, further research and interventions are necessary to mitigate the impact of tobacco smoke on TB control, especially in high-risk populations.

Cleaning products

Volatile organic compounds (VOCs) are gases that evaporate at room temperature and are commonly found in cleaning products. They can cause short- and long-term health issues, including headaches, nausea, and damage to vital organs like the liver, kidneys, and central nervous system. Even natural fragrances, such as citrus, can react with VOCs to produce dangerous indoor pollutants.

Paints, varnishes, waxes, and many cleaning, disinfecting, cosmetic, and hobby products contain organic solvents. These products release organic compounds during use and even while stored. The elevated levels of these compounds can persist in the air long after use, and their health effects range from highly toxic to no known impact.

To improve indoor air quality, it is essential to reduce sources of pollution and increase ventilation. Choosing cleaning products with reduced or no VOCs, fragrances, irritants, and flammable ingredients is recommended. Warm water and soap, or homemade cleaning solutions like baking soda and vinegar, are safer alternatives.

Additionally, using a well-chosen portable room air cleaner can help improve indoor air quality. Selecting a suitable device, such as an air purifier, and combining it with best practices recommended by public health agencies, can effectively reduce airborne pathogens. However, some air cleaning technologies emit ozone, a known lung irritant, so it is crucial to opt for third-party verified products that do not exceed safe levels of ozone generation.

Construction materials

Older building materials can be a particular concern. For example, homes built before 1978 are likely to contain lead paint, and asbestos was commonly used in insulation, floor and ceiling tiles, countertops, and shingles until the 1970s. Disturbing or removing these older materials during renovation or demolition can release dangerous chemicals and particles into the indoor air, posing a significant health risk.

Additionally, some construction materials may emit fumes or dust that can endanger health, especially when multiple products are used simultaneously, potentially mixing different chemical fumes. This can be a concern in new construction or remodeling projects.

To minimize the impact of construction materials on indoor air quality, it is essential to prioritize sustainable and pollutant-free building materials, low-VOC paints, and alternative chemicals that emit fewer harmful substances. Adequate ventilation during and after construction is also crucial to prevent the accumulation of indoor air pollutants.

Furthermore, the construction sector as a whole significantly impacts air quality, contributing to particulate matter, fine particulate matter, and nitrous oxide emissions. Construction activities generate dust, greenhouse gas emissions from diesel and fossil fuels, and carbon dioxide emissions from concrete production. Therefore, addressing construction-related air pollution requires a comprehensive approach, including strict regulations, innovative technologies, and sustainable practices.

Frequently asked questions