How Can You Improve Indoor Air Quality?

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Written By Jamila W.

According to the 2001 National Human Activity Pattern Survey (NHAPS), Americans spend almost 90% of their time indoors. With so much time spent in indoor spaces, poor indoor air quality will impact human health. Indoor air quality has been recognized by the Environmental Protection Agency and World Health Organization as a significant environmental health issue that needs to be addressed in large buildings and private residences. In this article, we share 12 strategies for reducing the common pollutants in room air.

12 ways to improve indoor air quality

girl smelling the air

Poor indoor air quality is a widespread problem. But there are many strategies to reduce pollutants in indoor air, improving air quality and occupant wellbeing. Here are 12 actionable steps for improving indoor air quality inside your property:

1. Undertake air quality testing 

Indoor air quality has subjective and objective elements. If you or the occupants of your property have air quality concerns, targeted IAQ testing can identify the indoor pollutant emissions that need to be reduced. 

Sensor-based technology measures the levels of common pollutants and airflow within the building. Sequential air quality measurements can be used to monitor air quality and ensure that pollutant levels are within safe limits. [1]

2. Use low-VOC paints and furnishings

Volatile organic chemicals (VOCs) like formaldehyde and benzene are hazardous substances emitted as gasses from everyday household products like paints, varnishes, interior decor, and furnishings. Environmental Protection Agency studies have found that the most common VOCs accumulate indoors at five times the levels these harmful chemicals are detected outside.

VOC emissions in indoor air can be reduced by switching to low- or zero-VOC paints and products. Indoor areas with high VOC emissions should be well-ventilated. If the source of the emissions can be identified, it should be removed or sealed 

3. Increase ventilation

Ventilation dilutes indoor air, reducing the concentration of pollutants present. [2] Mechanical ventilation can extract pollutants from the air and recirculate fresh air. Try these solutions to increase ventilation in your property:

  • Open windows and doors to bring in outdoor air and encourage airflow 
  • Use mechanical ventilation solutions like an exhaust fan and HVAC
  • Install vents and air bricks in the building structure to promote natural ventilation with outdoor air
  • Use a desk or standing fan to move air around the home

4. Reduce humidity

Humidity in properties reduces air circulation, allowing airborne pollutants to accumulate in room air. Mold growth is also driven by high humidity, especially where air moisture exceeds 50%. Tackle humidity in your property by

  • Ensuring that the property is well-ventilated when cooking or bathing
  • Addressing property construction issues that may be causing high humidity, dampness, or mold growth
  • Drying laundry outside or in a tumble dryer
  • Installing extraction fans in high-humidity areas
  • Regulating indoor temperature (see below)

5. Regulate indoor temperature

High room temperatures harm indoor air quality. In a warm room, the air becomes stagnant, preventing pollutants from being dispersed. Building and facilities managers are proactive in regulating the temperature in large buildings using a building energy management system (BEMS) that monitors and optimizes indoor temperature. [3]

Homeowners can install a smart thermostat that monitors indoor temperature and automatically adjusts the property’s heating or air conditioning to maintain an optimal temperature. 

6. Use an air purifier

An air purifier or air cleaner is a mechanical device that filters a range of pollutants including dust, pollen, and biologicals from indoor air. They come in a range of device formats including small standalone units and larger devices for use in medical or industrial settings. 

Air purifiers take in indoor air and pass it through a series of filters. Devices vary in their level of air intake and the level of filtration they can achieve.

Air purifiers with a HEPA or MERV 13 rating are capable of trapping particles as small as 0.3 micrometers in diameter. The cleaned exhaust air is free of allergens and particulates but it is important to note that an air purifier cannot remove gaseous indoor air pollutants. 

7. Install a high-efficiency air filter in HVAC systems

air filter

High-efficiency air filters are often used in environments that require a high degree of air cleanliness like operating theaters or clean rooms in electronics manufacturing facilities. These filters are capable of removing the smallest particles from room air, including biological agents like viruses

High-efficiency particulate arrestor (HEPA) filters are standardized filters that remove over 99.95% of 0.3-micrometer particles that pass through. HEPA filters meet efficiency standards the Department of Energy and the Environmental Protection Agency set. 

8. Clean HVAC air ducts

Air duct cleaning is a simple but effective way to improve the quality of room air. The ducts of air conditioning systems contain a range of contaminants including: 

  • Building debris
  • Dust and dirt
  • Mold
  • Allergens like pollen, pet dander, and dust mites
  • Bacteria and viruses

These substances will degrade air quality, causing allergies and odor. Accumulation of debris may also impede airflow, and raise energy costs. In the US, the National Air Duct Cleaners Association (NADCA) recommends that the ducts of an HVAC system should be professionally inspected annually and cleaned as required.

9. Stop smoking!

Environmental tobacco smoke (ETS) contributes to indoor air pollution. Active smokers introduce noxious volatile agents and particulates that cause acute and long-term respiratory and cardiovascular health problems for people who inhale their secondhand smoke in enclosed spaces. 

If you are a smoker, stopping smoking (or vaping) will remove a significant source of indoor air pollution from your environment. Smoking outside doesn’t produce an improvement in indoor air quality as the particulates are carried on clothes and continue to be exhaled into room air after smoking has ended.

10. Remove creosote from chimneys and furnaces

Burning wood in fireplaces, furnaces, and stoves generates a hazardous substance called creosote. This noxious substance is a tarry material that is formed from condensed unburned wood gasses and often coats chimneys, flues, and surfaces where wood has been burned.   


Creosote in indoor air causes a variety of health problems including

  • Respiratory tract irritation
  • Skin irritation
  • Eye irritation and sensitivity to bright lights
  • Liver and kidney disease
  • Congenital defects
  • Cancer

Creosote levels in indoor air can be effectively reduced by professional cleaning of chimneys and fireplaces.[4] This should be completed at regular intervals as creosote is flammable and can ignite causing a dangerous chimney fire. 

11. Service gas furnaces and stoves

Appliances that burn natural gas like furnaces and stoves require regular maintenance and servicing to ensure that they operate properly. Inefficient combustion of natural gas leads to the generation of carbon monoxide (CO) which is an extremely serious health risk.  If CO levels build up in a faulty appliance, it can be fatal to building occupants.

Appliances should be checked on an annual basis. Certified home heating technicians assess appliance safety and the condition of ducts and flues that remove exhaust air. By ensuring that appliances are operating efficiently and exhaust air is being removed from the home, you can ensure the safety of building occupants.

12. Clean your property to minimize allergens

Cleaning indoor environments is an effective way to improve air quality. In particular, basic cleaning tasks like vacuuming and removal of dust and dirt reduce the levels of dust, pet dander, mold, pollen, and other allergens that can cause respiratory discomfort. Accessible vents and air filters in the property should also be cleaned to prevent the recirculation of airborne contaminants. 

[BONUS] Will house plants improve indoor air quality?

home plants

Several research studies including the NASA Clean Air Study have suggested that certain house plant species can reduce indoor air pollution. A recent study published by the University of Birmingham in the UK showed that the Fern arum (Zamioculcas zamiifolia), Peace lily (Spathiphyllum wallisii), and Corn plant (Dracaena fragrans) could reduce levels of nitrogen dioxide in indoor environments by as much as 20%. 

However, opinion is divided over whether the benefits of houseplants on indoor air pollution are authentic. The Environmental Protection Agency does not recommend the use of indoor plants for improving air quality, pointing out that they can increase mold growth in the indoor environment and some species release pollutants.

Rounding up

Being proactive about the monitoring and improvement of indoor air quality will promote the health, well-being, and comfort of building occupants. There are a variety of strategies for reducing the levels of common indoor air pollutants. By implementing even the simplest methods, you can make a big difference in the air quality of your property.