How to Improve Indoor Air Quality Naturally: 10 Practical Ways to Breathe Cleaner Air at Home

How to Improve Indoor Air Quality Naturally: 10 Practical Ways to Breathe Cleaner Air at Home

When we think about air pollution, we usually think about busy roads, industrial emissions, or outdoor PM2.5. But the air inside your home can also contain fine particles, gases, allergens, mould, and other pollutants.

The good news is that improving indoor air quality (IAQ) doesn't always require expensive equipment. Many effective steps are surprisingly simple: reduce pollution at its source, ventilate when outdoor air is clean, control moisture, clean regularly, and use filtration when necessary.

The U.S. Environmental Protection Agency (EPA) broadly recommends three approaches to improving indoor air quality: source control, ventilation, and air cleaning or filtration. (EPA)

So, instead of looking for one "natural" solution, think of indoor air quality as a system.

Remove what makes the air dirty. Bring in clean air. Filter what remains.

Here's how to put that into practice.

1. Start by Identifying the Biggest Sources of Indoor Pollution

Before buying an air purifier, look around your home for things that may actually be polluting the air.

Common indoor pollutants include:

• PM2.5: tiny particles produced by cooking, combustion, smoking, and outdoor pollution entering the home

• VOCs: gases released by paints, cleaning products, furnishings, solvents, and other materials

• Nitrogen dioxide (NO₂): commonly associated with combustion, particularly gas appliances

• Carbon monoxide (CO): a dangerous, odorless gas produced by incomplete combustion

• Mould: biological contaminants that can grow when buildings remain damp

• Dust, pollen, and pet allergens: particles that can trigger or worsen symptoms in susceptible people

• CO₂: not usually the primary pollutant of concern, but elevated levels can indicate inadequate ventilation

According to the EPA, indoor air problems can result from indoor pollution sources combined with inadequate ventilation. (EPA)

That means the first question shouldn't be:

"Which air purifier should I buy?"

It should be:

"What's making the air in my home polluted?"

If you can eliminate the source, you don't have to remove that pollution later.

2. Ventilate Your Home When Outdoor Air Is Clean

Fresh outdoor air can dilute pollutants that accumulate indoors.

Opening windows and doors can increase ventilation, while kitchen and bathroom exhaust fans that vent outdoors can remove pollutants directly from the home. The EPA recommends increasing outdoor-air ventilation when weather and outdoor air conditions permit. (EPA)

Try cross-ventilation

If possible, open windows on opposite sides of a room or home.

This creates a pathway for air to enter through one opening and leave through another, helping replace stale indoor air.

You can improve airflow by:

• Opening windows on opposite sides of the home

• Opening interior doors to connect airflow pathways

• Using window or exhaust fans

• Ventilating bathrooms after showers

• Running the kitchen exhaust while cooking

But there's an important catch:

Opening your windows isn't always beneficial.

If outdoor PM2.5, smoke, or pollen levels are high, opening windows can bring those pollutants indoors.

A simple rule is:

Clean outdoor air → ventilate.

Polluted outdoor air → keep outdoor pollution out and rely more on source control and filtration.

You can check the outdoor air quality before deciding when to ventilate. For more on controlling fine particles indoors, see AQIRadar's How to Reduce PM2.5 Inside Your Home.

3. Keep Indoor Humidity Around 30–50%

Humidity is an often-overlooked part of indoor air quality.

The EPA recommends maintaining indoor relative humidity around 30–50%. Keeping humidity below 60% can also help reduce conditions that support mould growth. (EPA)

Persistently damp buildings are associated with respiratory symptoms, allergies, and asthma, according to the World Health Organization's guidelines on dampness and mould. (WHO)

If your home is too humid

You can:

• Use bathroom exhaust fans during and after showers

• Vent cooking moisture outdoors

• Repair plumbing and roof leaks

• Dry wet areas quickly

• Improve airflow in poorly ventilated rooms

• Use a dehumidifier where necessary

The EPA recommends addressing moisture problems and drying wet materials promptly rather than simply covering up the problem. (EPA)

If your home is too dry

A humidifier can increase indoor humidity, but it needs to be cleaned regularly.

A poorly maintained humidifier can itself become a source of biological contamination.

The simplest approach is to measure humidity first with a hygrometer rather than guessing.

4. Control Cooking Pollution

Cooking can produce significant indoor air pollution.

Gas cooking can release combustion pollutants such as NO₂ and CO, while frying, grilling, and other high-temperature cooking methods can generate fine particles.

Research published through the U.S. EPA found that natural-gas cooking can produce substantial pollutant emissions and that range hoods can substantially reduce pollutant concentrations, although their effectiveness varies depending on design and use. (EPA HERO)

Make your kitchen healthier

Whenever possible:

1. Turn on your range hood when you begin cooking.

2. Use a hood that vents outdoors rather than simply recirculating air.

3. Keep the hood running after cooking.

4. Use rear burners when practical.

5. Avoid heavily charring food.

6. Clean the hood and its filters regularly.

7. Open a window when outdoor air quality is good.

Cooking is one reason indoor particle concentrations can change dramatically over short periods.

And remember:

Never use a gas oven as a heater.

The CDC warns that using a gas oven to heat a home can create a carbon monoxide poisoning risk. (CDC)

5. Reduce Smoke and Unnecessary Combustion

One of the simplest ways to improve indoor air is to stop creating unnecessary pollution indoors.

Avoid smoking inside the home. Also consider limiting unnecessary indoor combustion sources such as:

• Candles

• Incense

• Unvented combustion appliances

• Indoor charcoal burning

• Poorly maintained fireplaces

• Unvented kerosene or gas heaters

Combustion can release particles, nitrogen dioxide, and carbon monoxide. (EPA)

Carbon monoxide deserves particular attention because it is colorless and odorless and can cause serious illness or death at high concentrations. (CDC)

If your home contains gas, oil, or other fuel-burning appliances, make sure they are properly installed, vented, and maintained.

A carbon monoxide detector is also an important safety measure in homes with combustion appliances.

6. Keep Dust and Allergens Under Control

Dust doesn't simply disappear when it settles on a surface.

Walking, cleaning, and moving furniture can disturb settled particles and put them back into the air.

Regular cleaning can therefore help reduce dust and allergen reservoirs.

Build a simple cleaning routine

Vacuum carpets and upholstery regularly.

If possible, use a vacuum with HEPA filtration designed to reduce the amount of captured material exhausted back into the room. (EPA)

Damp-dust hard surfaces.

A damp cloth or mop can capture settled dust without disturbing as much of it into the air.

Wash bedding regularly.

Bedding can accumulate dust, skin particles, and allergens.

Keep unnecessary clutter under control.

Fewer dust-collecting surfaces can make regular cleaning easier.

Cleaning won't solve every indoor-air problem, but it is an inexpensive way to reduce particulate and allergen reservoirs.

7. Choose Low-Emission Products and Materials

Your home can release pollutants even when nobody is actively doing anything.

Paints, varnishes, adhesives, cleaning products, furnishings, and building materials can release volatile organic compounds (VOCs).

EPA studies have found concentrations of some organic pollutants indoors approximately 2–5 times higher than outdoors in the homes studied. (EPA)

Some activities can produce much larger temporary increases.

When buying products, consider:

• Low- or no-VOC paints

• Lower-emission adhesives and sealants

• Lower-emission furniture

• Water-based finishes where appropriate

• Products with clear emissions information

Also avoid unnecessarily storing opened containers of:

• Paint

• Solvents

• Fuels

• Adhesives

• Strong cleaning chemicals

• Pesticides

EPA recommends reducing exposure to VOC-emitting products through source control, appropriate storage, and ventilation during use. (EPA)

What about air fresheners?

"Fresh-smelling" does not necessarily mean "clean air."

Fragranced products and air fresheners can release chemical compounds into indoor air.

If improving IAQ is the goal, removing unnecessary emissions is generally more useful than masking odors.

8. Don't Expect Houseplants to Purify Your Home

Houseplants are often presented as a natural alternative to air purifiers.

The idea comes partly from early laboratory research showing that plants could remove certain VOCs under controlled conditions.

But a normal home is very different from a sealed laboratory chamber.

A 2019 analysis of previous plant studies found that the number of plants required to achieve VOC removal comparable to normal building ventilation could be extremely large—roughly 10–1,000 plants per square meter, depending on the assumptions and conditions. (PubMed)

In practical terms:

A few houseplants should not be treated as an air-cleaning system.

Plants can still be enjoyable and contribute to the appearance and comfort of a home. But they should not replace:

• Ventilation

• Source control

• Moisture control

• Effective filtration

There is also a practical concern with excessive watering: persistently wet soil can contribute to unwanted microbial growth.

So keep the plants if you enjoy them—but don't expect a living-room jungle to replace proper ventilation or filtration.

9. Use HEPA Filtration When You Need Extra Particle Removal

"Natural" indoor-air improvement doesn't have to mean avoiding technology completely.

Sometimes filtration is the most practical way to reduce airborne particles, particularly when outdoor pollution is high or indoor sources cannot be completely eliminated.

A HEPA filter is a high-efficiency mechanical filter. Under the commonly used U.S. definition, HEPA filters can remove at least 99.97% of particles at 0.3 micrometers under specified test conditions. (EPA)

That doesn't mean 0.3 micrometers is the smallest particle a HEPA filter can capture. The 0.3-micrometer figure is associated with the particle size used in the standard efficiency rating.

If you're new to HEPA filtration, see AQIRadar's HEPA Filters Explained Simply.

But don't choose a purifier based only on "99.97%"

Real-world performance also depends on:

• CADR

• Room size

• Airflow

• Operating time

• Filter condition

• Filter sealing

• Indoor pollution sources

The EPA recommends selecting an air cleaner with a CADR appropriate for the room and notes that portable air cleaners can supplement source control and ventilation. (EPA)

HEPA filters primarily target particles, not gases.

If VOCs or odors are the main concern, source control, ventilation, and appropriate gas-phase filtration such as activated carbon may be necessary.

10. Consider a DIY Corsi–Rosenthal Air Cleaner

If a commercial purifier isn't practical, a DIY air cleaner can be another option for particle pollution.

A typical Corsi–Rosenthal-style cleaner combines a box fan with MERV-13 filters.

EPA research has examined DIY air cleaners using box fans and MERV-13 filters as a relatively inexpensive approach to reducing indoor smoke concentrations. (EPA)

The basic concept is simple:

Fan → filter → cleaner air

The advantage is that a properly constructed unit can provide substantial particle-cleaning airflow at relatively low cost.

However, construction quality matters.

Make sure:

• The fan is appropriate for the application.

• Filters are installed securely.

• Air cannot easily bypass the filters.

• The unit is placed where airflow isn't obstructed.

• Filters are replaced when dirty.

DIY filtration can be particularly useful during periods of heavy outdoor smoke when commercial air cleaners are unavailable or unaffordable.

What About MERV-13 HVAC Filters?

If your home has a compatible central HVAC system, upgrading filtration can help reduce airborne particles.

The EPA recommends using MERV 13 or the highest-efficiency filter your system can accommodate, provided the HVAC system can handle the additional resistance. (EPA)

Don't automatically install the highest-rated filter available.

A filter that is too restrictive for your HVAC system can create airflow problems.

If you're unsure, check the HVAC manufacturer's specifications or ask a qualified professional.

The key point is that these interventions solve different problems.

Ventilation dilutes indoor pollutants when outdoor air is clean.

Source control prevents pollution from being generated.

Filtration removes airborne particles.

Humidity control addresses moisture-related problems.

No single intervention does everything.

A Simple 30-Day Indoor Air Quality Plan

You don't have to change everything at once.

Today

• Stop smoking indoors.

• Check for obvious moisture leaks.

• Turn on the kitchen exhaust while cooking.

• Ventilate bathrooms after showers.

• Remove unnecessary sources of smoke and strong chemical emissions.

• Check outdoor AQI before opening windows.

This Week

• Start regular vacuuming and damp-dusting.

• Measure indoor humidity.

• Clean kitchen and bathroom exhaust fans.

• Check your HVAC filter.

• Identify products that may be releasing strong VOCs.

• Improve cross-ventilation where practical.

Within a Few Weeks

• Fix leaks or persistent dampness.

• Replace a heavily loaded HVAC filter.

• Consider a HEPA air purifier for rooms where people spend the most time.

• Consider a DIY MERV-13 air cleaner if appropriate.

• Switch to lower-emission products when replacing paints, cleaners, or furnishings.

Over the Next Few Months

• Schedule HVAC maintenance if necessary.

• Consider improving whole-home ventilation.

• Address persistent mould or dampness at the source.

• Plan low-emission materials for future renovations.

• Review your indoor-air routine and adapt it to seasonal outdoor pollution.

The 3-Part Formula for Cleaner Indoor Air

If you remember only one framework from this guide, remember this:

1. Remove the source

Stop indoor smoking, control cooking emissions, fix leaks, and reduce unnecessary chemical emissions.

2. Bring in clean air

Ventilate when outdoor air quality is suitable.

3. Filter what remains

Use appropriate particle filtration when source control and ventilation aren't enough.

This approach closely follows the EPA's hierarchy of source control, ventilation, and air cleaning. (EPA)

And that's why improving indoor air "naturally" isn't about finding one magical plant, ingredient, or household trick.

It's about managing the sources and pathways that determine what you actually breathe.

Frequently Asked Questions

What is the easiest way to improve indoor air quality?

Start with source control and ventilation. Stop indoor smoking, use kitchen and bathroom exhaust fans, control moisture, clean regularly, and ventilate when outdoor air is clean.

Should I open my windows every day?

Not necessarily.

Opening windows can improve ventilation when outdoor air is clean, but it can also bring outdoor PM2.5, smoke, or pollen indoors.

Check outdoor air quality before ventilating.

Do houseplants really clean indoor air?

Plants can remove certain VOCs under laboratory conditions, but evidence suggests that ordinary numbers of houseplants have little practical effect on indoor VOC concentrations. They should not replace ventilation or filtration. (PubMed)

What humidity should I keep my home at?

The EPA recommends maintaining indoor relative humidity around 30–50%. (EPA)

Does cooking affect indoor air quality?

Yes. Cooking can generate particles, while gas cooking can also produce combustion pollutants such as NO₂ and CO. Using an exhaust hood that vents outdoors can help reduce exposure. (EPA HERO)

Does a HEPA purifier remove VOCs?

Not primarily.

HEPA filters are designed to remove particles. VOCs are gases, so reducing VOC exposure may require source control, ventilation, or appropriate gas-phase filtration. (EPA)

Can I improve indoor air quality without buying an air purifier?

Yes.

Source control, ventilation, moisture control, cleaning, and proper exhaust can all improve indoor air quality without purchasing a purifier.

Filtration is a supplement rather than a replacement for these measures.

Final Takeaway

Improving indoor air quality naturally doesn't require turning your home into a laboratory.

Start with the basics:

Stop pollution at the source.

Ventilate when outdoor air is clean.

Keep humidity under control.

Clean dust and allergens regularly.

Use exhaust ventilation while cooking and showering.

Choose lower-emission products.

Use HEPA or other appropriate filtration when additional particle removal is needed.

And don't rely on houseplants as a substitute for actual ventilation or air cleaning.

The most effective indoor-air strategy is usually a combination of several simple actions rather than one expensive solution.

For more on reducing fine particles indoors, read AQIRadar's How to Reduce PM2.5 Inside Your Home. To understand filtration, see HEPA Filters Explained Simply. And for the relationship between air quality and sleep, see Air Quality and Sleep.

Sources & References

1. U.S. Environmental Protection Agency — Improving Indoor Air Quality
   Source control, ventilation, and air cleaning strategies.
   EPA — Improving Indoor Air Quality

2. U.S. Environmental Protection Agency — Care for Your Air: A Guide to Indoor Air Quality
   Guidance covering humidity, ventilation, cleaning, and household practices.
   EPA — Care for Your Air

3. U.S. Environmental Protection Agency — Volatile Organic Compounds' Impact on Indoor Air Quality
   Information on VOC sources, indoor concentrations, and exposure reduction.
   EPA — VOCs and Indoor Air Quality

4. U.S. Environmental Protection Agency — Air Cleaners and Air Filters in the Home
   Guidance on portable air cleaners and filtration.
   EPA — Air Cleaners and Air Filters

5. U.S. Environmental Protection Agency — What Is a HEPA Filter?
   Explanation of HEPA filtration and its particle-removal performance.
   EPA — What Is a HEPA Filter?

6. U.S. Environmental Protection Agency — What Is a MERV Rating?
   Guidance on HVAC filtration and MERV ratings.
   EPA — What Is a MERV Rating?

7. U.S. Environmental Protection Agency — Research on DIY Air Cleaners to Reduce Wildfire Smoke Indoors
   Research on DIY air cleaners using box fans and MERV-13 filters.
   EPA — DIY Air Cleaners Research

8. World Health Organization — WHO Guidelines for Indoor Air Quality: Dampness and Mould
   Evidence concerning dampness, mould, and associated health effects.
   WHO — Dampness and Mould Guidelines

9. CDC — Carbon Monoxide Poisoning Basics
   Information on carbon monoxide exposure and prevention.
   CDC — Carbon Monoxide

10. CDC — Don't Heat Your Home with a Gas Oven
    Safety guidance regarding carbon monoxide risks from using gas ovens for heating.
    CDC — Gas Oven Safety

11. Cummings & Waring (2019) — Potted plants do not improve indoor air quality
    Analysis of previous studies investigating plant-based VOC removal.
    PubMed — Potted Plants and Indoor Air Quality

12. Singer et al. — Pollutant concentrations and emission rates from natural gas cooking burners
    Research examining pollutants generated by gas cooking and range-hood performance.
    EPA HERO — Natural Gas Cooking Research

Medical note: Improving indoor air quality can reduce exposure to pollutants, but individual health effects vary. This article is educational and does not diagnose, treat, or prevent medical conditions.