What are the main sources of indoor air pollution?

The main sources of indoor air pollution are tobacco smoke, building materials, household products, and heating and cooking appliances.

Tobacco smoke is a significant source of indoor air pollution. It contains over 4,000 chemicals, many of which are known carcinogens. Passive smoking, or second-hand smoke, can lead to serious health problems such as lung cancer and heart disease. Even if smoking is done outside, harmful particles can still be brought indoors on clothing and other materials.

Building materials can also contribute to indoor air pollution. Asbestos, used in many buildings for its fire-resistant properties, can release fibres into the air that can be inhaled, leading to diseases such as asbestosis and mesothelioma. Other materials, such as certain types of insulation, can emit formaldehyde gas, a known carcinogen.

Household products, including cleaning supplies, air fresheners, and personal care products, can release a variety of chemicals into the air. These can include volatile organic compounds (VOCs), which can cause symptoms ranging from eye, nose, and throat irritation to liver and kidney damage. Pesticides used in homes can also contribute to indoor air pollution.

Heating and cooking appliances, particularly those that burn fuel, can produce a range of pollutants. These can include carbon monoxide, a colourless, odourless gas that can cause symptoms such as headaches, dizziness, and at high levels, death. Other pollutants can include nitrogen dioxide, which can cause respiratory problems, and particulate matter, which can exacerbate conditions such as asthma and heart disease.

In addition, biological sources such as mould, bacteria, viruses, pet dander, and dust mites can contribute to indoor air pollution. These can cause a range of health problems, particularly in individuals with allergies or asthma. Finally, outdoor air pollution can also infiltrate indoors, contributing to the overall level of indoor air pollution. This can include pollutants such as ozone, particulate matter, and pollen.