How to Improve Indoor Air Quality at Home and in the Office

Indoor air is typically 2–5 times more polluted than outdoor air. Not necessarily because homes and offices are visibly dirty, but because modern buildings are sealed well enough to trap pollutants with nowhere to go. Better ventilation, consistent source control, and the right filtration make the most meaningful difference. 

Here's what to prioritize, room by room and desk by desk, to improve air quality at home and in the office.

Quick Wins to Improve Indoor Air Quality Immediately

These 5 changes have the most immediate impact, no major purchases or structural changes required:

• Open windows for cross-ventilation. Two windows open on opposite sides of the building (or room) creates airflow that allows indoor pollutants to escape more easily. Ten minutes in the morning before outdoor traffic peaks is enough to make a meaningful difference.

• Replace or upgrade your HVAC filter. A clogged filter will stop effectively capturing particles and may recirculate them instead. Look for filters rated MERV-8 at minimum; MERV-13 captures the finest airborne particles. Both are widely available at hardware and home improvement stores, labeled clearly by their MERV rating.

• Remove shoes at the door. Tracked-in soil carries pesticides, heavy metals, and biological matter. It's one of the simplest source-control steps available and consistently underestimated.

• Run the kitchen exhaust when cooking. Gas cooking releases harmful gases and fine particles directly into the room; electric cooking produces chemical fumes from heated surfaces. Running exhaust ventilation during and for 15 minutes after cooking reduces these concentrations significantly.

• Vacuum twice a week with a HEPA-filter vacuum. Dust on floors re-enters the air with foot traffic. Frequency matters more than duration here.

Why Indoor Air Quality Matters More Than Most People Realize

Americans spend around 90% of their time indoors. For most of us, that makes indoor air quality a more significant daily health factor than outdoor pollution, yet it's the one we’re the least likely to monitor or actively manage.

Most buildings today are designed to prioritize energy efficiency rather than air exchange. Insulation, sealed windows, and weather-stripping keep heat in, but they also keep fresh air out. 

Without deliberate ventilation, pollutants from cooking, cleaning products, furniture off-gassing, and biological sources accumulate steadily in your home throughout the day.

The health effects of poor indoor air quality range from short-term symptoms - headaches, fatigue, eye irritation - to long-term respiratory and cardiovascular impacts. 

Fine particulate matter (the microscopic particles found in smoke, dust, and combustion fumes) carries the strongest documented health association. Particles at this size bypass the nose and throat entirely, settling deep in lung tissue and, in some cases, entering the bloodstream.

Sleep is another factor that rarely gets discussed in this context. Research consistently links indoor air pollution to poor sleep outcomes, including reduced sleep efficiency, more frequent disturbances, and a higher risk of sleep-disordered breathing.

3 Most Important Factors That Affect Indoor Air Quality

While dozens of variables affect the air you breathe indoors, 3 account for the majority of what determines whether it's genuinely clean or quietly problematic.

1. Ventilation and Air Exchange

Ventilation determines how quickly indoor pollutants are diluted by fresh outdoor air. The relevant measure is air changes per hour (ACH) - how many times the total air volume in a room is replaced within an hour. 

Most homes achieve around 0.35 air changes per hour through natural infiltration, which is the minimum recommended by ASHRAE for residential spaces and is rarely enough to keep pace with everyday pollutant sources.

Without adequate exchange, pollutant concentrations rise throughout the day. That’s why indoor air quality is often worse in the evening in sealed homes, because pollutants have built up for hours with no outlet.

2. Humidity Levels and Why Balance Matters

The EPA recommends keeping indoor relative humidity between 30–50%. Both extremes create problems, and this is one area where most guidance is incomplete.

Below 30%, mucous membranes dry out and lose their natural filtration capacity, making respiratory infections more likely. Above 60%, conditions favor mold growth and dust mite reproduction, both of which are significant allergen sources. The goal isn't to add moisture; it's to stay within range.

A digital hygrometer (as little as $10 at some hardware stores) gives you accurate readings. Most people discover their home isn't where they assumed.

3. Everyday Sources of Indoor Pollution

Three categories account for most indoor pollutant load:

• Combustion: Gas stoves, candles, and incense produce nitrogen dioxide, carbon monoxide, and fine particles. A gas stove running in a poorly ventilated kitchen can raise airborne particle levels to concentrations classified as "unhealthy" within minutes of use.

• VOC off-gassing: Paints, adhesives, new furniture, cleaning products, and personal care products (hairsprays, aerosol sprays, synthetic fragrances) release volatile organic compounds (VOCs) - chemical gases that linger in the air for days, weeks, or months. Formaldehyde deserves a specific mention: found in engineered wood, flooring, and some insulation materials, it's one of the most persistent sources (continuing to off-gas for years in some cases) and is present in virtually every modern home.

• Biological sources: Mold spores, pet dander, dust mite debris, and pollen tracked in from outside. These are the primary triggers for allergy and asthma symptoms and are present in virtually every occupied home.

Identifying which category your main sources fall into determines which interventions will actually help to improve your indoor air quality.

Long-Term Habits That Keep Indoor Air Cleaner Year-Round

Build a Consistent Cleaning and Ventilation Routine

The most effective long-term approach is to reduce pollutant accumulation at the source consistently. That means:

• Making sure to ventilate the house daily. Consistent timing (first thing in the morning, for example) builds the habit and ensures pollutants don't accumulate overnight.

• Running kitchen and bathroom exhaust fans during use and for 15 minutes after.

• Cleaning with fragrance-free, low-VOC products and avoiding aerosol sprays indoors.

• Washing bedding weekly at 130°F (54°C) to kill dust mites and deep-cleaning mattresses and upholstered furniture monthly to remove accumulated dust, skin cells, and dander.

• Scheduling HVAC filter checks every 60–90 days.

The compounding effect of these habits over months is substantially larger than any single purchase or intervention.

Monitor Indoor Air Quality Instead of Guessing

Most people manage indoor air reactively, like opening a window when something smells off. But the problem is that pollutants are invisible (and often odorless), so you can't sense a problem until it's already been building for hours.

Real-time monitoring removes the guesswork. The Dreame PM10 and PM20 Air Purifiers continuously monitor microscopic particles, chemical gas levels, and additional pollutants, with live readings that tell you what's in your air before it becomes a problem. 

They also adjust their purification speed automatically when those pollutant levels rise, so you're not relying on manual checks to catch changes.

Monitoring your air quality means you’re being proactive rather than reactive.

How to Improve Indoor Air Quality at Home

The foundation is the same across all homes: reduce sources, increase ventilation, filter what remains. The specifics vary by room.

Room-by-Room Air Quality Tips

Air Quality Considerations for Homes With Pets, Allergies, or Young Children

These homes need to close the gap between general maintenance and active filtration. 

Pet dander particles range from 0.5–100 microns, and that’s fine enough that standard cleaning doesn't fully capture them. 

Children breathe more air per pound of body weight than adults, which means their pollutant exposure at any given concentration is proportionally greater. That makes consistent air filtration, not just during allergy season, especially important in households with young children.

The practical implication: HEPA-grade filtration in key rooms matters more in these homes than average.

How to Improve Indoor Air Quality in Office Spaces

Office air quality is harder to control than home air quality, for reasons that rarely get discussed. 

Shared HVAC systems serve multiple occupants across different floors and uses, meaning individual control over air exchange rates is limited. 

Also, open-plan layouts allow pollutants to travel more freely than in spaces closed off with doors. 

Office-specific sources (laser printers, synthetic carpet, large numbers of people sharing a sealed space) add a pollutant load that most home guides don't address, too.

Practical Changes at a Personal or Desk Level

• Position your workstation away from printer areas (if you can). Laser printers emit ultrafine particles and VOCs during every print job. Distance makes a measurable difference.

• Keep a CO2 monitor at desk level. A Harvard T.H. Chan School of Public Health study of more than 300 office workers across 6 countries found that elevated fine particle concentrations and carbon dioxide - both common in standard office buildings - were directly associated with slower response times and reduced accuracy on cognitive tests. Carbon dioxide above 1,000 ppm is the threshold where effects become measurable.

• Avoid aerosols and strong fragrances in shared spaces. Products that seem minor at an individual desk contribute to the collective chemical load across an open floor.

• Stay hydrated. Dry office air dries out the sensitive linings of your nose and airways, which reduces your body's natural first line of defense against airborne particles.

Building and Shared Space Improvements

At a facilities or management level, the highest-impact changes are upgrading HVAC filters to MERV-13 minimum, scheduling regular duct cleaning, and increasing outdoor air intake where the system allows.

Where central ventilation is insufficient or difficult to modify, standalone air purifiers for office spaces address the gap at a room or zone level. 

The key specification is CADR (clean air delivery rate) relative to the room's actual square footage - a unit rated for 200 sq ft (18.5m²) will not meaningfully improve air quality in an open-plan floor of 1,000 sq ft (93m²). The Dreame PM20 covers up to 1,883 sq. ft. (175m²) in 15 minutes, making it a practical choice for shared spaces where air quality shifts throughout the working day.

Do Air Purifiers Actually Improve Indoor Air Quality?

Yes, under two conditions: the unit needs to be sized for the space it's actually serving, and it needs to run continuously, not just when something smells off.

Using an air purifier intermittently in a room that's continuously generating pollutants won't keep pace. Three things determine whether it actually works:

• Match CADR to your room size. As a rule, look for a CADR (in m³/h) roughly double your room's floor area in square meters. A 20m² (215 sq. ft.) bedroom needs around 150–200 m³/h; a 40m² (430 sq. ft.) living room needs 300 m³/h or more.

• Position it near the source, not the wall. Place the purifier toward the room's main pollutant source, like beside the bed rather than across the room, or near the cooking area rather than in a corner. Central placement with clearance on all sides maximizes airflow.

• Run it continuously, or use a purifier with an auto mode that adjusts output based on live pollutant levels. Cycling between off and full power clears air in peaks and then lets pollutants rebuild. Auto mode means the unit responds to what's actually in the air rather than running on a fixed schedule.

Create a Cleaner Indoor Environment With Smarter Daily Habits

Most homes should see a meaningful improvement within a few weeks of applying even a handful of these changes consistently. The gap between where most indoor air quality sits and where it could be is smaller than it seems, and the effort required is considerably less than most people expect.

If you're starting from scratch, begin with ventilation and filter maintenance, then add monitoring and active filtration as your baseline improves. Explore Dreame's range of air purifiers for the whole house and for offices to find the right fit for your space.

Frequently Asked Questions

How Do You Improve Air Quality in a Room Without Windows?

Run your HVAC system on fresh-air intake mode with a MERV-13 filter, or install an energy recovery ventilator (ERV) as a more permanent solution; it exchanges stale indoor air with fresh outdoor air without significant heat loss. A standalone air purifier handles particle filtration in the meantime. A carbon dioxide monitor is especially useful here: levels above 1,000 ppm tell you whether ventilation is keeping pace with the number of people in the space.

What Are the Cheapest Ways to Improve Indoor Air Quality?

The highest-impact steps cost little or nothing. Cross-ventilation, running kitchen exhaust during cooking, and removing shoes at the door are all free. A digital hygrometer tracks whether your humidity sits in the EPA-recommended 30–50% range. Upgrading your existing HVAC filter to MERV-13 is the most cost-effective filtration step available, working through the system you already have.

How Do You Improve Air Quality in a Home Without an Air Purifier?

Ventilation and source control are the two highest-impact strategies that don't require filtration equipment. Open windows for cross-ventilation daily, run kitchen and bathroom exhaust fans consistently, reduce combustion sources (candles, gas cooking) and VOC sources, use a HEPA-filter vacuum twice weekly, and manage humidity with a hygrometer.

Can Indoor Plants Improve Indoor Air Quality?

Modestly, and not in the way most people expect. The original NASA research on plants and air purification involved sealed chambers with very high plant densities; conditions that don't reflect normal living spaces. In a typical room, you'd need hundreds of plants to achieve measurable air-cleaning effects. The genuine benefit of indoor plants is humidity regulation and psychological well-being. Worth having for those reasons, but not a replacement for ventilation or filtration.

References:

1. U.S. Environmental Protection Agency - Improving Your Indoor Environment: https://www.epa.gov/indoor-air-quality-iaq/improving-your-indoor-environment

2. U.S. Environmental Protection Agency - Inside Story: A Guide to Indoor Air Quality: https://www.epa.gov/indoor-air-quality-iaq/inside-story-guide-indoor-air-quality

3. U.S. Environmental Protection Agency - Mold and Health: https://www.epa.gov/mold/mold-and-health

4. U.S. Environmental Protection Agency - Children Are Not Little Adults: https://www.epa.gov/children/children-are-not-little-adults

5. U.S. Environmental Protection Agency - How much ventilation do I need in my home to improve indoor air quality?: https://www.epa.gov/indoor-air-quality-iaq/how-much-ventilation-do-i-need-my-home-improve-indoor-air-quality

6. Harvard T.H. Chan School of Public Health - Office air quality may affect employees' cognition, productivity: https://hsph.harvard.edu/news/office-air-quality-may-affect-employees-cognition-productivity/

7. Cedeño Laurent et al. (2021) - Associations between acute exposures to PM2.5 and carbon dioxide indoors and cognitive function in office workers, Environmental Research Letters: https://iopscience.iop.org/article/10.1088/1748-9326/ac1bd8

8. Vert et al. (2020) - Air pollution exposure and adverse sleep health across the life course: A systematic review, Environmental Pollution: https://pmc.ncbi.nlm.nih.gov/articles/PMC7877449/