People spend almost 90% of their time indoors.1 Unfortunately, internal air is two to five times more polluted than outside and can quickly become 100 times worse.2 

But all is not lost. Acknowledging this modern reality is a crucial first step toward everyone breathing better. 


Article overview:

  • Pollution is worse indoors than outdoors
  • Information is power: improvement starts with measurement
  • Small adjustments equal big improvements
  • Open the windows, curtains, and blinds more often


What is indoor air pollution?

When most people imagine pollution, the idea is factory smoke stacks, rotting landfills, and radioactive waste dumps. But while these striking examples are significant, it’s the pollution inside our homes, businesses, and even schools that can make a greater impact on health.3 

Simply put, physical, chemical, and biological pollutants are damaging to health; even small concentrations of these detrimental substances cause drowsiness, rashes, nausea, headache, and irritation to eyes, noses, and throats. Higher levels and/or increased exposure can negatively impact the kidneys, liver, central nervous system, etc.4


Indoor pollution can be simplified into three categories: 

  1. Particulate Matter (PM): These are small pieces of solids and liquids floating in the air and collecting on the ground as dust.
  2. Gasses: This category highlights carbon monoxide (CO), carbon dioxide (CO2), and nitrogen dioxide (NO2). However, there are other problematic gases like radon, ozone (O3), etc.
  3. Volatile Organic Compounds (VOCs): These are a diverse group of airborne chemicals mostly caused by heating, cooking, and using chemical cleaners/products. Some are harmful alone, while others react in contact with other materials to become hazardous. 


Tips and tricks to beat indoor air pollution

Modern structures have evolved to be increasingly effective at protecting inhabitants. Ironically, better sealing and thicker insulation also trap unwanted materials inside with heating. Widespread combinations of poor ventilation and inefficient air conditioning have given rise to so-called sick building syndrome (SBS).5 

However, reducing and even beating indoor pollution is understandable. So, let’s take a deep breath, and go over some realistic methods on how to fix things. 


1. Start monitoring indoor air quality (IAQ)

It’s difficult to make improvements without data. Here, using measuring devices provide updates on health-centric metrics like CO2, temperature, humidity, etc. Additionally, these numbers directly correlate to airborne pathogen levels: influenza, RSV, the common cold, etc. 

Furthermore, with a tracking system in place, it becomes possible to measure the difference between actions: like following the steps below.

Measurement from Aranet4 HOME IAQ monitor app


2. Open the windows frequently

Fresh air is just that: fresh. Allowing an outside breeze in is a great way to improve IAQ. However, it’s worth considering the timing that shutters open. “10 to 100 percent of indoor air pollution consists of outdoor air pollution that has infiltrated indoor air,” according to Health Risks of Indoor Exposure to Particulate Matter.6

Considering this, it’s best to avoid certain high-pollution times like the big-city traffic peaks of mid mornings and early evenings.


3. Invite the sunlight in

In addition to playing a central role in vitamin D production for brain, bone, and heart fitness, sunshine also helps regulate human sleep cycles. But while these factors are key to staying healthy, sunlight directly kills harmful bacteria and viruses – even when screened through window glass.7 Lab experiments conducted on unlit rooms relative to areas exposed to sunlight showed bacteria survival rates of 12% and 6.8%, respectively. That’s a big difference. 

Doctors and healers of all kinds prescribe sunlight as treatment.8 But while it used to be common knowledge that sunlight was instrumental to well-being, it seems humanity is destined to continually rediscover its utility. 


4. Keep things clean

It makes sense that a bit of surface dusting, floor vacuuming, sheet washing, and other common tidying activities are useful. Additionally, pet dander, dust mites, and allergens continually build up on their own – even without foreign materials being tracked in. 

Speaking of, developing the habit of removing shoes at the door or foyer goes a long way toward keeping the outside outside. 


5. Add some leafy plants

In addition to fostering a healthy-looking environment, certain plants are claimed to help purify indoor air9. During the photosynthetic process, plants literally absorb CO2 and release clean oxygen as a byproduct. It’s worth noting certain plants (like the peace lily and snake plant) have been shown to be exceptionally effective at purifying air.10 


6. Mitigate mold growth 

It’s well worth identifying damp locations that can prompt mold growth. Areas that stay wet or experience high humidity are prone to breeding dust mites, mold spores, insects, and other unwanted inhabitants. To beat these effects, consider:

  • Using an air monitor to regulate humidity
  • Drying clothing outside
  • Buying a dehumidifier
  • Letting more sunlight into the home
  • Scrubbing and cleaning problematic spots in the home


7. Practice clean cooking

Significant amounts of indoor air pollution are created by ovens and stoves: nitrogen dioxide (NO2), formaldehyde (CH2O), and carbon monoxide (CO) are foremost. And while gas burners are notorious for decreasing IAQ11, electric appliances also release these detrimental substances. 

A quick fix is to use stove hoods and fans when cooking. Furthermore, cracking a window for some natural ventilation makes a big difference. A final cooking tip is to use the burners located further back on a stove. This helps working hoods and fans catch more grease, fumes, particles, etc. 


8. Optimize heating, ventilation, and air conditioning (HVAC) systems

Many buildings and homes have different infrastructure for ventilation and temperature regulation. So, it’s rare that there’s a one-size-fits all solution. However, there are several proven ways to boost HVAC performance. 

  • Regulate temperature: Ideally, the range should hover between 20-24°C (68-75.2°F) during winter and 24-27°C (75.2-80.6°F) in summer.12
  • Monitor humidity: Indoor parameters should range between 30-50%.13
  • Clean vents and filters: If bacteria, mold, dust mites, or other harmful particles build up within an HVAC system, these problems could be dispersed throughout an entire structure. Removing the source is key.
  • Upgrade equipment: For high-risk areas, consider adding an air purification system (APU) or install a high-efficiency particulate arrestance (HEPA) filter.
  • Determine optimal air flows: It’s possible that low-traffic or unused spaces take up resources and energy for no reason. Once identified, these areas can be reduced or routed away from. 





  1. Klepeis, N. (2001). The National Human Activity Pattern Survey (NHAPS): A resource for assessing exposure to environmental pollutants.
  2. Ritchie, Hannah. “Indoor Air Pollution. 11 Jan. 2022,
    “Indoor Air Vs. Outdoor Air Pollution.”
  3. Indoor Air Pollution: Sources and Effects.
  4. How to Improve Your Indoor Air Quality at Home.
  5. Health Risks of Indoor Exposure to Particulate Matter.
  6. Daylight exposure modulates bacterial communities associated with household dust.
  7. Want to Kill Dangerous Bacteria? Open Your Blinds.
  8. Interior Landscape Plants for Indoor Air Pollution Abatement.
  9. Air Purifying Plants.
  10. Kitchen Air Quality and Ventilation.
  11. 13 HVAC tips for improving air quality and avoiding disease.
  12. What Temperature Should I Set My Air Conditioner in Summer?.

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