{"id":80534,"date":"2026-04-10T04:05:05","date_gmt":"2026-04-10T11:05:05","guid":{"rendered":"https:\/\/www.redfin.com\/blog\/?p=80534"},"modified":"2026-04-09T09:59:34","modified_gmt":"2026-04-09T16:59:34","slug":"indoor-air-pollution","status":"publish","type":"post","link":"https:\/\/www.redfin.com\/blog\/indoor-air-pollution\/","title":{"rendered":"Indoor Air Pollution: Causes, Effects, and How to Improve Your Indoor Air Quality"},"content":{"rendered":"

People spend about <\/span>90%<\/span><\/a> of their time indoors. While smoke-filled skies and hay fever dominate the news cycles, indoor air pollution is just as important and often much harder to avoid. Smoke, vapors, mold, and more can all affect indoor air quality and lead to long-term health effects.<\/span><\/p>\n

So, what is indoor air pollution, how does it impact you, and how can you improve the indoor air quality in your home? Whether you live in a <\/span>home in Boston<\/span><\/a>, or an <\/span>apartment in Round Rock, TX<\/span><\/a>, read on to learn more.<\/span><\/p>\n

What is indoor air pollution?<\/span><\/h2>\n

Indoor air pollution<\/span> is air from indoor or outdoor sources<\/a> that is harmful to breathe in. It’s usually caused by chemicals, particulates, bacteria, and viruses in the air. Many of these pollutants are found in everyday products and chemicals, making them hard to avoid.\u00a0<\/span><\/p>\n

Additionally, outdoor air pollutants often leak indoors, affecting indoor air quality. Green, energy-efficient homes may offer a degree of protection. These homes often use higher-quality construction materials, better insulation, and newer HVAC systems that can reduce and remove chemicals and particulates. However, there is no perfect solution.<\/span><\/p>\n

Indoor air pollution can cause mild to severe health effects that can last a day to a lifetime. Some symptoms show up after only a short exposure to pollution, including headaches and a runny nose. Others show up after years of exposure.<\/span><\/p>\n

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What causes indoor air pollution?<\/span><\/h2>\n

Indoor air pollution comes from <\/span>biological and chemical sources<\/span><\/a>. Let’s break these down:<\/span><\/p>\n\n\n\n\n\n\n\n
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Biological indoor air pollution sources<\/span><\/h3>\n<\/td>\n<\/tr>\n

Mold<\/span><\/td>\nAnimal dander and saliva<\/span><\/td>\n<\/tr>\n
Bacteria<\/span><\/td>\nDust mites<\/span><\/td>\n<\/tr>\n
Viruses<\/span><\/td>\nBed bugs<\/span><\/td>\n<\/tr>\n
Pollen<\/span><\/td>\nBug waste<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u201cOne of the most commonly overlooked sources of indoor air pollution is hidden mold growth behind walls, under flooring, or inside HVAC systems.\u201d <\/span>Green Home Solutions<\/span><\/a> warns. \u201cThese areas are out of sight, so homeowners often do not realize an issue exists until it becomes widespread. In some cases, certain molds can also produce mycotoxins, which are microscopic, invisible compounds that impact indoor air quality.\u201d<\/span><\/p>\n\n\n\n\n\n\n\n\n
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Chemical indoor air pollution sources<\/span><\/h3>\n<\/td>\n<\/tr>\n

Carbon monoxide<\/span><\/td>\nLead<\/span><\/td>\n<\/tr>\n
Carbon dioxide<\/span><\/td>\nArsenic<\/span><\/td>\n<\/tr>\n
Ozone (residual)<\/span><\/td>\nTobacco smoke<\/span><\/td>\n<\/tr>\n
Radon (residual)<\/span><\/td>\nAsbestos<\/span><\/td>\n<\/tr>\n
Pesticides<\/span><\/td>\nVolatile organic compounds (VOCs)<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Other factors to consider<\/span><\/h3>\n

Levels of indoor air pollution vary widely depending on where you live. If you live near a large industrial area, you will likely experience higher levels of residual air pollution compared to people who live on top of a hill near the water.\u00a0<\/span><\/p>\n

Because <\/span>air pollution and economic status<\/span><\/a> are related, studies have indicated that lower-income people are exposed to more pollution. Additionally, older homes with poor insulation and inefficient appliances often have more air pollution.\u00a0<\/span><\/p>\n

Lastly, temperature, moisture, and humidity can affect the severity of air pollutants. For example, warmer temperatures can increase levels of outdoor airborne allergens, notably bacteria and pollen, which can then make their way into your home. High humidity also increases the concentration of toxic chemicals in the air and provides a good environment for dust mites.<\/span><\/p>\n

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What are VOCs?<\/span><\/h2>\n

Volatile organic compounds<\/span><\/a> (VOCs) are a large group of chemicals found in many everyday products. VOCs slowly release harmful gas (“off-gas”) that can cause significant adverse health effects, including long-term illnesses such as cancer and other chronic conditions. Many VOCs appear in higher concentrations indoors (up to five times higher) than they do outdoors, regardless of where you live.\u00a0<\/span><\/p>\n\n\n\n\n\n\n\n\n
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Common VOCs<\/span><\/h3>\n<\/td>\n<\/tr>\n

Benzene<\/span><\/td>\nTetrachloroethylene<\/span><\/td>\n<\/tr>\n
Ethylene glycol<\/span><\/td>\nToluene<\/span><\/td>\n<\/tr>\n
Formaldehyde<\/span><\/td>\nXylene<\/span><\/td>\n<\/tr>\n
Methylene chloride<\/span><\/td>\n1,3-Butadiene<\/span><\/td>\n<\/tr>\n
PFAS<\/span><\/a> (Perfluoroalkyls and Polyfluoroalkyls)\u00a0<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Unfortunately, avoiding contact with VOCs is nearly impossible. Your best option is to increase ventilation, limit exposure, and store unused chemicals and harmful products outdoors or in an enclosed area. If you can, choose products made from natural materials that don’t include harmful chemicals.\u00a0<\/span><\/p>\n\n\n\n\n\n\n\n
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Common products that contain VOCs<\/span><\/h3>\n<\/td>\n<\/tr>\n

Office equipment<\/b><\/td>\nInk, toner, printers, photocopiers, copy paper, glue, permanent markers<\/span><\/td>\n<\/tr>\n
Building materials<\/b><\/td>\nPatin, varnishes, adhesives, composite wood products, upholstery, foam, refrigerant, carpet, vinyl<\/span><\/td>\n<\/tr>\n
Everyday products<\/b><\/td>\nMany types of clothing (especially waterproof clothing), makeup, air fresheners, refrigerant<\/span><\/td>\n<\/tr>\n
Oil products<\/b><\/td>\nGasoline, petroleum, many plastics<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

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Effects of indoor air pollution<\/span><\/h2>\n

Poor indoor air quality can lead to <\/span>numerous health issues<\/span><\/a>. These include both short- and long-term effects, including:<\/span><\/p>\n