How to improve the air quality in your home?

Indoor air isn’t just “background”—it”’s the environment your lungs live in. Most people spend about 90% of their time indoors, where levels of some pollutants can be 2–5 times higher than outside (and occasionally even more).

Poor indoor air quality (IAQ) is linked to eye and throat irritation, headaches, fatigue, and worsened asthma and heart disease. Globally, air pollution (indoor and outdoor combined) is responsible for an estimated 6.7 million premature deaths every year. 

The good news: you can make your home’s air dramatically healthier with a mix of source control, better ventilation, filtration, and smart monitoring—without turning your life upside down.

What Causes Poor Indoor Air Quality?

Poor indoor air quality is usually caused by a combination of pollution sources inside the building, outdoor pollution that leaks in, and inadequate ventilation to dilute and remove contaminants.

Common sources include combustion (gas stoves, fireplaces), tobacco smoke, cleaning and fragrance products, building materials, furniture, mold, and moisture. Outdoor pollutants like traffic PM2.5 can also infiltrate indoors if windows or ventilation systems bring polluted air inside.

Key indoor pollutants to know

The main pollutant groups to focus on:

• Particulate matter (PM2.5, PM10, PM1)
  Tiny particles from cooking, candles, wood smoke, traffic, and wildfires. Fine particles (PM2.5 and below) penetrate deep into the lungs and are strongly linked with cardiovascular and respiratory disease.
• Volatile organic compounds (VOCs)
  Chemicals that off-gas from paints, cleaning products, air fresheners, furniture, and flooring. Some VOCs (like benzene or formaldehyde) are carcinogenic; others irritate eyes and airways or trigger headaches.
• Combustion gases (CO, NO₂)
  Generated by gas stoves, unvented heaters, fireplaces, and vehicle exhaust in attached garages. Nitrogen dioxide (NO₂) and carbon monoxide (CO) can reach harmful levels indoors if appliances are poorly vented.
• Ozone and secondary pollutants
  Ozone can be brought in with outdoor air or generated by some electronic “air cleaners” and can react with VOCs to form new irritant compounds.
• Biological contaminants
  Mold, dust mites, pet dander, bacteria, and viruses thrive when humidity is uncontrolled and cleaning is inconsistent.
• Legacy hazards (lead and asbestos)
  Older homes may still contain lead-based paint (especially pre-1978 housing) and building products with asbestos, which can release hazardous dust when disturbed.

Because these sources usually coexist, your indoor air problem is rarely “just one thing.” That’s why we approach IAQ as a system.

What Pollutants Should I Focus on Eliminating First?

Start with pollutants that are both common and strongly linked to health impacts: fine particles (PM2.5), combustion gases (CO, NO₂), and high VOC levels.

According to WHO, there is no safe level of PM2.5; even low concentrations increase health risks, which is why their guideline for annual average PM2.5 is just 5 µg/m³. For gases like NO₂ and CO, both WHO and national agencies set strict short-term limits to prevent acute health effects.

Most impactful targets:

• PM2.5 and PM1—From cooking, candles, incense, wood stoves, and outdoor pollution.
• Combustion gases (CO, NO₂) – From gas stoves, unvented heaters, fireplaces, and attached garages.
• High-emission VOC sources—Fragranced products, strong solvents, some paints and finishes.
• Mold and dampness—a consistent predictor of respiratory symptoms and asthma exacerbations.

By tackling these first through source control, ventilation, and filtration, you reduce a large share of the health burden from indoor air pollution.

How Do I Naturally Purify the Air in My House?

You can significantly improve indoor air quality with natural, low-tech measures: smarter ventilation, source control, and moisture management.

This doesn’t mean you never need a filter or air purifier—but it keeps pollution levels lower and reduces how hard your devices have to work.

1. Ventilate wisely (but not blindly).

Ventilation is about exchanging indoor air with cleaner outdoor air. If outdoor air quality is reasonably good, opening windows is one of the simplest and most effective ways to dilute indoor pollutants.

Practical tips:

• Open windows on opposite sides of the home to create cross-ventilation when outdoor air is clean.
• Ventilate during and after high-pollution activities: cooking, cleaning, painting, and showering.
• Always use your kitchen exhaust hood (vented outdoors) when cooking, especially with gas.
• In wildfire or heavy smog episodes, keep windows closed and rely on filtration instead.
  

2. Control sources before you chase “cures.”

Source control is the most reliable and cost-effective way to improve IAQ.

Key moves:

• No smoking indoors. Secondhand tobacco smoke is a major indoor pollutant and carcinogen.
• Choose low- or no-VOC products. Look for low-VOC paints, adhesives, and finishes.
• Switch to fragrance-free cleaning and personal care products. A study of 37 fragranced consumer products found 156 different VOCs in emissions; 42 were classified as toxic or hazardous under U.S. federal laws.
• Avoid plug-in and aerosol air fresheners. They emit VOCs (including terpenes and sometimes benzene and toluene) and can contribute to smog formation when these react in the air.
• Store solvents and paints tightly sealed and (if possible) outside the main living area, such as in a shed or well-ventilated garage.

Many of these recommendations build on earlier practical advice for cleaner home air—like avoiding air fresheners, being wary of fragranced cleaning products, and limiting combustion sources indoors.

3. Keep humidity in the “Goldilocks” zone.

Too dry and your eyes, skin, and airways become irritated; too humid and mold, dust mites, and bacteria flourish. Research suggests that keeping indoor relative humidity around 40–60% may support immune defenses and reduce transmission of some respiratory viruses. 

Practical steps:

• Use bathroom and kitchen exhaust fans during and after showering or cooking.
• Fix leaks and water damage promptly; dry wet materials within 24–48 hours.
• If the air is very dry, use a humidifier—but clean it regularly and avoid over-humidifying. Experts typically recommend staying near 40–60% RH to minimize both dryness and mold.

How to Filter the Air (HVAC Systems, Purifiers, and Vacuums)

Mechanical filtration physically removes particles from the air and is especially useful for PM2.5, pollen, and pet dander.

HVAC filters and air ducts: what actually helps?

Upgrading and maintaining your central HVAC filter is one of the highest-impact, low-effort actions you can take.

• Use the highest MERV rating your system can handle (often MERV 11–13 for residential systems).
• Change filters regularly. How often depends on usage, outdoor pollution, and pets, but clogged filters stop working effectively and may reduce airflow.

As earlier guidance noted, changing filters more frequently during heavy AC use or in homes with multiple pets is sensible; the exact interval should follow manufacturer recommendations.

On duct cleaning, the EPA is cautious: they do not recommend routine duct cleaning for all homes but advise considering it if there is substantial visible mold growth, vermin infestation, or ducts clogged with heavy dust and debris.

Portable air purifiers: how to choose and use them

A quality portable air purifier can significantly reduce particle levels in a room when correctly sized and operated.

• Look for units with a True HEPA filter. HEPA (high-efficiency particulate air) filters are defined in the U.S. as removing at least 99.97% of particles 0.3 microns in diameter.
• Prefer purifiers with both a HEPA filter for particles and an activated carbon filter for some VOCs and odors.
• Run the purifier on at least the medium setting continuously when the room is occupied for best results.
  

The original article rightly highlighted “True HEPA” purifiers as a strong defense against mold spores, pollen, and dust. Updating that advice: many home HEPA filters are changed every 6–12 months, but heavy pollution or 24/7 operation may require more frequent replacement per the manufacturer.

Does vacuuming improve indoor air quality?

Vacuuming improves IAQ over time by removing dust and particles from floors and fabrics—if your vacuum doesn’t just blow them back into the air.

The EPA recommends using vacuums with HEPA filters (or central systems vented outdoors), which reduce the amount of dust re-emitted into the room.

However, vacuuming can temporarily increase airborne particle levels while you clean, so people with asthma or allergies may want to leave the room until the dust settles. 

How Often Should I Ventilate or “Change” My Air?

There is no single magic number that works for every home, but the principle is simple: ventilate more when emissions are high and when outdoor air is clean enough to help.

Evidence-based guidance from agencies emphasizes:

• Use local exhaust (bathroom and kitchen fans) during and after activities that produce moisture or pollutants.
• Ensure mechanical ventilation systems are working as designed and that filters are maintained.
• During wildfire smoke or severe outdoor pollution, keep windows closed, use recirculation mode on HVAC, and rely on filtration.

If you have an air quality monitor that measures CO₂, you can use it as a rough proxy for ventilation: lower CO₂ (closer to outdoor levels, ~400–500 ppm) usually means a better fresh air supply, especially in crowded rooms.

How Do I Stop Mold and Moisture Problems?

To prevent mold, you must control moisture: fix leaks, manage humidity, and dry wet materials quickly.

EPA guidance on mold is very clear: mold will not grow without water or excessive moisture, and dampness problems should be addressed within 24–48 hours. 

Core actions:

• Fix leaks in roofs, walls, plumbing, and windows promptly.
• Dry wet materials (carpets, drywall, furniture) within 1–2 days. If that’s not possible, replacement may be safer.
• Use exhaust fans in bathrooms, kitchens, and laundry rooms.
• Keep relative humidity near 40–60%; use dehumidifiers in damp basements or climates.
• Clean and dry HVAC drip pans regularly to prevent mold colonies—a practical tip consistent with earlier guidance on weekly maintenance.

If you repeatedly see mold in air ducts or around HVAC components, you may need to address insulation or condensation issues and consider professional cleaning following EPA criteria. 

Which Household Items Pollute My Air the Most?

Some everyday items are surprisingly large contributors to indoor pollution. Prioritizing these gives you a big health payoff.

Major culprits include:

• Gas stoves and unvented combustion heaters
  Gas and propane stoves can contribute a large share of NO₂ exposure and have been linked to exposures exceeding WHO guidelines for short-term NO₂, especially in small or poorly ventilated kitchens.
• Fragranced cleaning and personal care products
  As noted earlier, a detailed analysis of 37 fragranced products found 156 VOCs, including 42 classified as toxic or hazardous.
• Candles and incense
  These generate fine particles and, in some cases, VOCs and soot, which can accumulate indoors, especially in poorly ventilated rooms.
• Old lead-based paint and lead dust (in homes built before 1978)
  Deteriorating lead-based paint and contaminated dust pose serious risks, especially for children.
• Asbestos-containing materials (in some homes built before ~1990)
  Disturbing materials that contain asbestos (e.g., some insulation, floor tiles) can release fibers that increase the risk of lung disease and cancers; intact materials should generally be left alone and assessed by professionals if damaged.

If you address even half of these, your indoor air will become significantly safer.

What Are the Symptoms of Poor Air Quality in a House?

Early symptoms of poor IAQ are often subtle: irritated eyes, nose, or throat; headaches; dizziness; fatigue; or trouble concentrating.

These symptoms may improve when you leave the building and worsen when you return, which is a classic clue that something indoors is contributing. Chronic exposure to polluted indoor air is linked with asthma, cardiovascular disease, and, for some pollutants like radon or tobacco smoke, cancer.

If you notice patterns (for example, headaches after cleaning with fragranced products or coughing after using a gas stove), that’s valuable diagnostic information—and a signal to change products or ventilation.

How Do I Improve Air Quality in Specific Spaces?

The principles are the same, but the details change a bit depending on where you live and what the space is like.

How to improve air quality in a bedroom

You spend a third of your life here, so improvements are high-impact.

• Use an HEPA purifier if you live in a polluted area or have allergies.
• Keep the room dust-minimized: wash bedding weekly in hot water, reduce clutter, and vacuum carpets and soft furniture with a HEPA vacuum.
• Avoid scented candles, incense, and plug-in air fresheners in the bedroom.
• Maintain humidity around 40–60% to limit dust mites and mold while keeping your airways comfortable.

How to improve air quality in an old house

Older homes often have character—and hidden hazards.

• Check for lead-based paint if the home was built before 1978; deteriorating paint and dust should be addressed using lead-safe methods and, when needed, professionals.
• Be aware that some building products used before about 1990 may contain asbestos; do not disturb suspect materials and consult certified professionals before renovations.
• Address chronic dampness in basements, crawlspaces, and around foundations; these are classic mold hot spots.

How to improve air quality in an apartment (especially in cities)

Apartments often have less control over building systems but still offer room for improvement.

• Use a room-sized HEPA purifier in the main living/sleeping areas.
• Seal obvious gaps around windows and doors to reduce infiltration from traffic or smoke, while still ventilating when outdoor air quality is acceptable.
• Always use the kitchen hood (ideally vented outdoors) when cooking, and avoid deep-frying on days with bad outdoor air.
• If you are near busy roads, ventilate at times of day when traffic and outdoor pollution are lower.
  

Do Indoor Plants Really Improve Air Quality?

Short answer: houseplants are lovely, but they are not a primary solution for indoor air pollution.

The famous 1989 NASA Clean Air Study found that plants in sealed chambers could remove VOCs from the air. However, later analyses concluded that you would need anywhere from 10 to 1,000 plants per square meter to replicate similar VOC removal in a typical home—which is obviously impractical. 

So, enjoy plants for their psychological benefits (reduced stress, improved mood, aesthetics), but rely on ventilation, filtration, and source control to genuinely improve IAQ.

How Can I Monitor and Track My Indoor Air Quality?

You can’t manage what you don’t measure. Affordable sensors now make it possible to see what’s in your air in real time.

Modern indoor air quality monitors can measure combinations of:

• Particulate matter (PM1, PM2.5, PM10)
• CO₂ (proxy for ventilation and crowding)
• VOCs
• Temperature and humidity

For example, portable monitors like Atmotube PRO are designed to track PM1, PM2.5, PM10, VOCs, CO₂, nitrogen oxides (NOx), temperature, humidity, and barometric pressure in real time, helping users decide when to ventilate or purify the air.

Using a monitor doesn’t replace healthy habits, but it:

• Reveals which activities spike pollution (for example, frying, cleaning with sprays, and burning candles).
• Helps you fine-tune ventilation and purifier use.
• Lets you compare different rooms or even different homes or workplaces.

Earlier guidance already emphasized the value of portable monitoring, and today’s devices have become more accurate and easier to use, often with app-based alerts when air quality drops below a healthy level.

Conclusion: A Simple Blueprint for Cleaner Indoor Air

Improving indoor air quality is less about buying a single “miracle” gadget and more about stacking many small, smart habits:

1. Control sources—No smoking indoors; minimize gas and open-flame use; choose low-VOC, fragrance-free products.
   
   
2. Ventilate wisely—Let in clean outdoor air when available; exhaust pollutants at the source; seal out smoke or smog when needed.
   
   
3. Filter effectively—Use good HVAC filters, HEPA purifiers, and HEPA vacuums.
   
   
4. Control moisture—Fix leaks quickly, manage humidity, and prevent mold.
   
   
5. Monitor your air—Use an IAQ monitor to learn what’s really happening and adjust your strategy.

You don’t have to fix everything overnight. Start with the changes that feel most doable in your life right now—swapping a few products, using the kitchen hood every time you cook, or placing a HEPA purifier in the room where you sleep. Each step makes your home a safer place for your lungs, your heart, and the people you care about.

FAQs

1. What causes poor indoor air quality?

Poor IAQ comes from indoor sources (cooking, heating, smoking, cleaning products, building materials, and mold) and outdoor pollution that leaks in, combined with insufficient ventilation.

2. How do I naturally purify the air in my house?

Focus on source control (no smoking, low-VOC and fragrance-free products), good ventilation when outdoor air is clean, and humidity control around 40–60%. These steps reduce pollutants before you even think about devices. 

3. What are the symptoms of poor air quality in a house?

Common early symptoms include eye, nose, and throat irritation, headaches, dizziness, fatigue, and worsened asthma or allergies. Symptoms that improve when you leave the building and reappear when you return are a strong clue. 

4. Does vacuuming improve air quality?

Yes, over time. Vacuuming removes dust and allergens from floors and fabrics, especially when you use a HEPA-equipped vacuum so particles aren’t blown back into the room. In the short term, vacuuming can stir up dust, so sensitive people may want to avoid the room during and just after cleaning.

5. How can I improve indoor air quality without an air purifier?

You can still make big improvements by:

• Ventilating during and after cooking, cleaning, and showering
• Switching to low-VOC, fragrance-free products
• Controlling humidity and fixing leaks
• Using a good HVAC filter and cleaning regularly.

6. How can I improve air quality in my bedroom?

Keep the bedroom low-clutter and dust-reduced, wash bedding weekly in hot water, vacuum with a HEPA vacuum, and avoid scented candles or plug-in air fresheners. If you live in a polluted area or have allergies, consider a small HEPA purifier and maintain humidity around 40–60%.

7. Do houseplants improve indoor air quality?

Not in a meaningful way on their own. While plants can remove VOCs in sealed chambers, real-world homes would need unrealistically large numbers of plants to match those effects. They’re still great for mood and stres—justt don’t rely on them as your primary “air purifier.”

8. How often should I change my HVAC filter?

It depends on your system, filter type, and conditions, but many manufacturers recommend changing filters every 1–3 months during heavy use and at least every season. Homes with pets, smokers, or heavy outdoor pollution may need more frequent changes, while higher-end filters may last longer if specified.

9. What indoor air quality levels should I aim for at home?

Aim to keep PM2.5 as low as reasonably achievable, ideally around or below WHO’s annual guideline level of 5 µg/m³, and avoid spikes. For CO₂ (if your monitor measures it), keeping indoor levels not too far above outdoor (often <1,000 ppm in occupied rooms) is a practical ventilation target.

10. How do I know if my home’s air is unhealthy?

Look for symptoms (irritation, headaches, fatigue), visible mold or dampness, strong chemical or musty odors, and frequent condensation on windows. The most objective way is to use an indoor air quality monitor to track PM, VOCs, CO₂, temperature, and humidity over time.