The air inside your home is 2 to 5 times more polluted than outdoor air, according to the EPA — and Americans spend roughly 90% of their time indoors. Understanding what's in your air, how to measure it, and how to fix it isn't optional anymore; it's a health priority that affects everything from your sleep quality to your long-term cancer risk.
This guide covers every indoor air pollutant you need to know about, the exact testing methods professionals use, EPA and WHO threshold values, and the proven strategies that actually move the needle on air quality. Whether you're dealing with allergies, new construction off-gassing, or just want peace of mind, you'll find actionable data here.
What Is Indoor Air Quality (IAQ) and Why Does It Matter?
Indoor air quality (IAQ) refers to the condition of the air inside buildings as it relates to the health and comfort of occupants. It's determined by the concentration of pollutants — particulate matter, volatile organic compounds, carbon dioxide, carbon monoxide, radon, and biological contaminants — along with temperature and humidity levels.
The health stakes are enormous. The World Health Organization attributes 3.2 million deaths annually to indoor air pollution globally. In the United States, the EPA ranks indoor air pollution among the top five environmental health risks. Poor IAQ has been linked to asthma, cardiovascular disease, cognitive decline, and multiple cancers.
The Indoor Air Problem by the Numbers
| Metric | Value | Source |
|---|---|---|
| Indoor vs. outdoor pollution ratio | 2–5× worse indoors | EPA |
| Time Americans spend indoors | ~90% | EPA |
| Homes with at least one IAQ problem | 96% | ASHRAE studies |
| Annual US deaths from radon exposure | ~21,000 | EPA |
| Annual US CO poisoning deaths | ~420 | CDC |
| Productivity loss from poor IAQ | 6–9% | Harvard T.H. Chan |
| Children's asthma cases linked to indoor allergens | 40% | NIH |
| Average number of VOCs in a typical home | 50–300+ compounds | EPA Total Exposure Assessment |
Your HVAC system is the single biggest factor in indoor air quality. It controls filtration, ventilation, humidity, and air circulation — the four pillars of IAQ management. A poorly maintained system doesn't just waste energy; it actively degrades your air.
The Six Major Indoor Air Pollutants
Understanding what you're breathing is step one. Here are the six pollutant categories that matter most in residential settings, their sources, and the concentration thresholds you should know.
1. Particulate Matter (PM2.5 and PM10)
Particulate matter refers to tiny particles suspended in air. PM2.5 (particles under 2.5 micrometers) is the most dangerous because it penetrates deep into your lungs and enters your bloodstream.
Common indoor sources: Cooking (especially frying and grilling), candles, incense, fireplaces, tobacco smoke, vacuuming without HEPA filtration, and pet dander.
| PM2.5 Level (µg/m³) | Rating | Health Impact |
|---|---|---|
| 0–12 | Good | Minimal risk |
| 12.1–35.4 | Moderate | Sensitive groups may be affected |
| 35.5–55.4 | Unhealthy for Sensitive Groups | Increased respiratory symptoms |
| 55.5–150.4 | Unhealthy | General population affected |
| 150.5–250.4 | Very Unhealthy | Significant health effects |
| 250.5+ | Hazardous | Emergency conditions |
The WHO's 2021 guideline recommends annual average PM2.5 exposure below 5 µg/m³ — far stricter than the EPA's 12 µg/m³ standard. Cooking a single meal on a gas stove can spike indoor PM2.5 to 200+ µg/m³ for 30–60 minutes.
Real-World Example: The Cooking Spike A family in Denver installed an Aranet4 Home monitor and discovered that frying bacon with their range hood off pushed PM2.5 from a baseline of 8 µg/m³ to 340 µg/m³ in under 10 minutes. Turning on their range hood (vented to outdoors) dropped levels back to baseline within 15 minutes. That single behavior change eliminated their biggest daily PM2.5 exposure event.
2. Volatile Organic Compounds (VOCs)
VOCs are gases emitted from solids or liquids that include a variety of chemicals, some of which have short- and long-term adverse health effects. Indoor concentrations are consistently 2 to 5 times higher than outdoor levels.
Common indoor sources: Paints, varnishes, cleaning supplies, building materials, new furniture, air fresheners, dry-cleaned clothing, adhesives, and personal care products.
| VOC | Common Source | EPA/WHO Guideline | Health Effect |
|---|---|---|---|
| Formaldehyde | Pressed wood, insulation | 0.1 ppm (WHO 30-min) | Carcinogen (Group 1) |
| Benzene | Attached garages, tobacco | No safe level (WHO) | Leukemia risk |
| Toluene | Paints, adhesives | 8 ppm (EPA RfC) | Neurological effects |
| Xylene | Paints, lacquers | 0.1 ppm (chronic) | Respiratory irritation |
| Styrene | Plastics, insulation | 0.85 ppm (OSHA) | Possible carcinogen |
| Trichloroethylene | Spot removers | No safe level (EPA) | Liver/kidney damage |
| Acetaldehyde | Pressed wood, tobacco | 0.14 mg/m³ (EPA) | Respiratory irritation |
Total VOC (TVOC) readings from consumer monitors provide a general indicator but don't identify specific compounds. A TVOC reading below 0.3 mg/m³ is considered good; above 3.0 mg/m³ indicates a significant problem.
For a deep dive, see our dedicated guide: VOCs in Your Home: Sources, Dangers, and How to Remove.
3. Carbon Dioxide (CO2)
CO2 is a metabolic byproduct that builds up in occupied spaces with insufficient ventilation. While not toxic at typical indoor levels, elevated CO2 is the single best proxy for overall ventilation adequacy and has measurable cognitive effects.
| CO2 Level (ppm) | Rating | Significance |
|---|---|---|
| 400–450 | Outdoor baseline | Fresh outdoor air (2026 global average ~425 ppm) |
| 450–700 | Excellent | Well-ventilated indoor space |
| 700–1,000 | Good | ASHRAE 62.2 target range |
| 1,000–1,500 | Fair | Drowsiness and reduced concentration begin |
| 1,500–2,500 | Poor | Significant cognitive impairment (15–25%) |
| 2,500–5,000 | Very Poor | Headaches, fatigue, poor decision-making |
| 5,000+ | Dangerous | OSHA workplace limit; health hazard |
A landmark 2015 Harvard study found that cognitive function scores dropped 21% at 1,000 ppm and 53% at 1,400 ppm compared to 600 ppm. Your bedroom CO2 levels can easily reach 2,000–3,000 ppm overnight with doors and windows closed.
4. Carbon Monoxide (CO)
Carbon monoxide is an odorless, colorless gas produced by incomplete combustion. It's the leading cause of accidental poisoning deaths in the United States.
Common indoor sources: Gas furnaces, water heaters, gas stoves, fireplaces, attached garages (vehicle exhaust), generators, and tobacco smoke.
| CO Level (ppm) | Exposure Duration | Health Effect |
|---|---|---|
| 0 | — | Ideal |
| 1–9 | Chronic | Normal indoor background |
| 9–35 | 8 hours | EPA max 8-hour exposure |
| 35–100 | Hours | Headache, dizziness |
| 100–200 | 2–3 hours | Severe headache, impaired judgment |
| 200–400 | 1–2 hours | Life-threatening |
| 400+ | Minutes | Fatal |
For placement guidelines, see our complete guide: Carbon Monoxide Detector Placement Guide.
5. Radon
Radon is a naturally occurring radioactive gas that seeps into homes through foundation cracks and gaps. It's the second leading cause of lung cancer after smoking, responsible for approximately 21,000 lung cancer deaths annually in the US.
| Radon Level (pCi/L) | Risk Level | Action Required |
|---|---|---|
<2.0 | Low | No action needed |
| 2.0–3.9 | Moderate | Consider mitigation |
| 4.0+ | High | EPA action level — mitigate |
| 8.0+ | Very High | Urgent mitigation |
| 20.0+ | Extreme | Equivalent to smoking 1 pack/day |
The EPA's action level is 4.0 pCi/L, but the WHO recommends action at 2.7 pCi/L. About 1 in 15 US homes has radon levels at or above 4.0 pCi/L. Testing is the only way to know — radon levels vary dramatically from house to house, even on the same street.
6. Biological Contaminants
This category includes mold, dust mites, pet dander, pollen, bacteria, and viruses. Biological contaminants thrive when humidity exceeds 60% and are a leading trigger for allergies and asthma.
| Contaminant | Ideal Indoor Level | Problem Threshold | Primary Health Effect |
|---|---|---|---|
| Mold spores | <500 spores/m³ | >1,000 spores/m³ | Allergic reactions, respiratory issues |
| Dust mites | <2 µg/g allergen | >10 µg/g allergen | Asthma trigger |
| Pet dander (Fel d 1) | <1 µg/g | >8 µg/g | Allergic reactions |
| Bacteria | <500 CFU/m³ | >1,000 CFU/m³ | Infection risk |
| Indoor humidity | 30–50% RH | >60% RH | Promotes all biological growth |
If you can see mold or smell a musty odor, your mold problem is already significant. By the time mold is visible, the spore count in your air is likely 5–10× what it should be. Don't wait for visible growth — monitor humidity and address water intrusion immediately.
How to Test Your Indoor Air Quality
Testing transforms IAQ from guesswork into data. Here's every testing method available, from free DIY approaches to professional assessments.
Tier 1: Free Self-Assessment
Start with what you can observe. These indicators don't replace measurements, but they flag obvious problems:
- Condensation on windows — indicates excess humidity (likely >60% RH)
- Musty or chemical odors — suggests mold or VOC issues
- Visible mold anywhere — confirms active biological contamination
- Stuffy feeling / headaches when home — classic CO2 or ventilation issue
- Dust accumulation within days of cleaning — filtration problem
- Symptoms that improve when you leave — strong IAQ indicator
Tier 2: Consumer Air Quality Monitors ($50–$400)
Consumer monitors provide continuous real-time data for the pollutants that matter most. This is the single best investment most homeowners can make for IAQ awareness.
| Monitor | Price Range | Measures | Best For |
|---|---|---|---|
| Aranet4 Home | $200–$250 | CO2, temp, humidity | CO2/ventilation tracking |
| AirThings View Plus | $300–$330 | PM2.5, CO2, VOC, radon, temp, humidity | Comprehensive monitoring |
| Temtop M10i | $80–$100 | PM2.5, HCHO, TVOC, AQI | Budget PM2.5/VOC |
| IQAir AirVisual Pro | $270–$300 | PM2.5, CO2, temp, humidity | PM2.5 accuracy |
| uHoo Smart Air Monitor | $350–$400 | PM2.5, CO2, VOC, CO, O3, NO2, temp, humidity | Most parameters |
| Purple Air PA-I-Indoor | $200–$230 | PM2.5, PM10, temp, humidity | PM research-grade |
For detailed reviews and comparisons, see: Best Indoor Air Quality Monitors.
Pro tip: Place your monitor in the room where you spend the most time (usually the bedroom or home office). Run it for at least 2 weeks before drawing conclusions — IAQ varies dramatically by time of day, weather, and activity. Look for patterns, not single readings.
Tier 3: DIY Test Kits ($10–$200)
Some pollutants require specific test kits rather than continuous monitors:
| Test | Cost | Method | Turnaround |
|---|---|---|---|
| Radon — short-term | $10–$25 | Charcoal canister, 2–7 days | 1–2 weeks (lab) |
| Radon — long-term | $20–$40 | Alpha track, 3–12 months | 2–4 weeks (lab) |
| Mold — air sampling | $30–$50 | Cassette air sampler | 5–10 days (lab) |
| Lead paint | $10–$30 | Swab test | Instant |
| Asbestos | $25–$40 | Sample collection + lab | 5–10 days (lab) |
| Water — VOCs | $100–$200 | Sample kit + lab | 7–14 days (lab) |
| Formaldehyde | $30–$100 | Passive badge, 24–72 hrs | 5–10 days (lab) |
Tier 4: Professional IAQ Assessment ($200–$1,500+)
Professional testing makes sense when you have persistent symptoms, are buying a home, or need legal documentation (mold disputes, workplace complaints).
| Service | Typical Cost | What You Get |
|---|---|---|
| Basic IAQ inspection | $200–$400 | Visual inspection, moisture readings, basic pollutant screening |
| Comprehensive IAQ assessment | $400–$800 | Multi-point testing for PM, VOC, CO2, CO, mold, plus written report |
| Full environmental testing | $800–$1,500+ | All of above plus radon, formaldehyde, specific VOC identification via GC/MS |
| Mold inspection + air sampling | $300–$600 | Visual inspection, moisture mapping, lab-analyzed air samples |
| Duct system inspection | $200–$400 | Camera inspection, airflow testing, contamination assessment |
Real-World Example: The New Construction Problem A couple in Austin, TX moved into a newly built home and experienced persistent headaches and eye irritation. A professional IAQ assessment ($650) found formaldehyde levels of 0.08 ppm — just under the WHO guideline — along with TVOC readings of 2.4 mg/m³. The source was primarily engineered wood flooring and kitchen cabinets off-gassing. The solution: they ran their HVAC fan continuously with MERV-13 filters, opened windows for 30 minutes daily, and added activated carbon filtration. After 6 weeks, formaldehyde dropped to 0.02 ppm and TVOCs fell below 0.4 mg/m³.
Indoor Air Quality Standards and Guidelines
Multiple organizations set IAQ standards. Here's a consolidated reference table showing the thresholds that matter for residential settings.
| Pollutant | EPA Standard | WHO Guideline | ASHRAE 62.2 | OSHA PEL | Recommended Home Target |
|---|---|---|---|---|---|
| PM2.5 (24-hr) | 35 µg/m³ | 15 µg/m³ | — | — | <12 µg/m³ |
| PM2.5 (annual) | 12 µg/m³ | 5 µg/m³ | — | — | <5 µg/m³ |
| CO2 | — | — | <1,000 ppm above outdoor | 5,000 ppm | <800 ppm |
| CO (8-hr) | 9 ppm | 4 ppm (24-hr) | — | 50 ppm | <2 ppm |
| Formaldehyde | — | 0.08 ppm (30-min) | — | 0.75 ppm | <0.05 ppm |
| Radon | 4.0 pCi/L | 2.7 pCi/L | — | — | <2.0 pCi/L |
| Relative humidity | — | — | 30–60% | — | 40–50% |
| TVOC | — | — | — | — | <0.3 mg/m³ |
| Ozone (8-hr) | 0.070 ppm | 0.050 ppm | — | 0.1 ppm | <0.050 ppm |
ASHRAE Standard 62.2-2022 is the primary residential ventilation standard in the US. It specifies minimum ventilation rates based on home size and number of occupants. For a typical 2,000 sq ft home with 4 occupants, it requires a minimum continuous mechanical ventilation rate of approximately 60 CFM.
How Your HVAC System Affects Indoor Air Quality
Your HVAC system is the backbone of your home's IAQ infrastructure. It controls four of the five IAQ fundamentals: filtration, ventilation, humidity, and circulation. Here's how each component contributes.
Filtration — Your First Line of Defense
The air filter in your HVAC system processes your home's entire air volume 5–8 times per day. Filter efficiency is measured by MERV (Minimum Efficiency Reporting Value) rating.
| MERV Rating | Captures | Best For | Pressure Drop |
|---|---|---|---|
| MERV 1–4 | Pollen, dust mites, textile fibers | Minimum protection (most builder-grade) | Very low |
| MERV 5–8 | Mold spores, pet dander, dust | Basic residential | Low |
| MERV 9–12 | Fine dust, legionella, humidifier dust | Good residential | Moderate |
| MERV 13–16 | Bacteria, smoke, sneeze droplets, most virus carriers | Excellent residential / commercial | Moderate–High |
| MERV 17–20 (HEPA) | Viruses, carbon dust, combustion smoke | Hospitals, cleanrooms | Very high |
The sweet spot for most homes is MERV 13. It captures 85%+ of PM2.5 particles while maintaining acceptable airflow in most residential HVAC systems. Going above MERV 13 requires verifying your system can handle the increased static pressure.
Never install a filter with a higher MERV rating than your HVAC system can handle. An overly restrictive filter reduces airflow, causes the evaporator coil to freeze, increases energy consumption by 5–15%, and can shorten compressor life. Check your system manual or ask your HVAC tech for the maximum MERV rating.
Ventilation — Dilution Is the Solution
Ventilation brings in fresh outdoor air to dilute indoor pollutants. Without mechanical ventilation, modern airtight homes can accumulate CO2, VOCs, and moisture to unhealthy levels.
There are three ventilation strategies:
- Exhaust-only ventilation — Bath fans and range hoods exhaust stale air; fresh air enters through leaks. Simple but uncontrolled.
- Supply-only ventilation — Outdoor air is ducted into the return plenum. Provides some filtration but no energy recovery.
- Balanced ventilation (ERV/HRV) — The gold standard. Simultaneously exhausts stale air and brings in fresh air through a heat exchanger, recovering 70–85% of heating/cooling energy.
For a detailed comparison, see: Whole-House Ventilation Systems: ERV vs HRV.
Humidity Control
Humidity outside the 30–50% range accelerates virtually every IAQ problem:
- Below 30% RH: Dried mucous membranes, increased virus survival, static electricity, wood cracking
- Above 60% RH: Mold growth, dust mite proliferation, bacterial growth, musty odors
- Sweet spot: 40–50% RH for health, comfort, and building preservation
Your HVAC system's evaporator coil naturally dehumidifies during cooling cycles. In humid climates, this may not be sufficient, and a whole-house dehumidifier (integrated into the HVAC system or standalone) may be needed. In dry climates, a whole-house humidifier attached to the furnace plenum maintains adequate moisture levels.
Air Circulation and Distribution
Even with great filtration and ventilation, poor distribution means some rooms get clean air and others don't. Key factors:
- Ductwork condition — Leaky ducts can pull in attic/crawlspace contaminants. Duct leakage of 25–40% is common in older homes.
- Register placement — Blocked or closed registers create dead zones.
- Fan operation — Running the HVAC fan continuously (not just during heating/cooling cycles) improves distribution and filtration.
- Duct cleaning — Necessary only if visible mold, vermin, or excessive debris is present. Routine duct cleaning has limited proven benefit.
Real-World Example: The Leaky Ductwork Problem A homeowner in Atlanta wondered why their allergies were worse at home despite using MERV-13 filters. An HVAC contractor performed a duct leakage test and found 33% of their supply air was leaking into the attic before reaching living spaces. Worse, the return duct had a large gap pulling in fiberglass-contaminated attic air. Sealing the ducts with mastic cost $800 and reduced PM2.5 levels from an average of 18 µg/m³ to 6 µg/m³ — a 67% improvement.
Room-by-Room IAQ Concerns
Different rooms have different IAQ challenges. Here's what to prioritize in each space.
Kitchen
The kitchen is the single largest source of indoor PM2.5 in most homes. Gas stoves emit nitrogen dioxide (NO2), carbon monoxide, and formaldehyde in addition to particulate matter. Even electric stoves produce significant PM2.5 during high-heat cooking.
Priority actions: Always use your range hood (vented to outdoors) when cooking. A range hood removing 200+ CFM at the point of cooking captures 60–80% of cooking pollutants. Recirculating range hoods are far less effective — they remove some grease and odors but almost zero PM2.5 or combustion gases.
Bedroom
You spend 7–9 hours in your bedroom with doors and windows typically closed. CO2 levels routinely reach 1,500–3,000 ppm by morning in bedrooms with poor ventilation. This impairs sleep quality and next-day cognitive function.
Priority actions: Ensure adequate ventilation (crack a window or run the HVAC fan), use MERV-13 filtration, encase mattresses and pillows in allergen-proof covers, and consider a portable air purifier with HEPA filtration.
Bathroom
High humidity from showering promotes mold growth. Inadequate exhaust fans leave moisture on surfaces for hours.
Priority actions: Run a properly sized exhaust fan (minimum 50 CFM for small bathrooms, 1 CFM per sq ft for larger ones) for at least 20 minutes after showering. Consider a humidity-sensing fan that runs automatically.
Basement
Basements face radon infiltration, higher humidity, and potential mold growth due to below-grade moisture. They're also where many homes' HVAC equipment, water heaters, and furnaces are located — all potential CO sources.
Priority actions: Test for radon, maintain humidity below 50% with a dehumidifier, ensure combustion appliances are properly vented, and install CO detectors.
Garage (Attached)
Attached garages are a major pathway for vehicle exhaust (including benzene and CO), gasoline fumes, and chemical storage off-gassing to enter your living space.
Priority actions: Seal the wall and door between garage and living space, never idle vehicles in the garage, install a CO detector near the garage entry, and consider exhaust ventilation in the garage.
10 Proven Methods to Improve Indoor Air Quality
Here's a quick priority list. For the full detailed breakdown of each method, see: How to Improve Indoor Air Quality: 10 Proven Methods.
| Rank | Method | Effectiveness | Cost | Difficulty |
|---|---|---|---|---|
| 1 | Upgrade HVAC filter to MERV 13 | ★★★★★ | $15–$30/filter | Easy |
| 2 | Use range hood when cooking | ★★★★★ | $0 (existing) | Easy |
| 3 | Control humidity (40–50% RH) | ★★★★☆ | $0–$1,500 | Easy–Moderate |
| 4 | Increase ventilation (ERV/HRV) | ★★★★★ | $1,500–$4,000 | Professional |
| 5 | Add portable HEPA air purifier | ★★★★☆ | $100–$600 | Easy |
| 6 | Test and mitigate radon | ★★★★★ | $800–$2,500 | Professional |
| 7 | Seal ductwork | ★★★★☆ | $500–$1,500 | Professional |
| 8 | Eliminate source pollutants | ★★★★☆ | $0–$500 | Easy |
| 9 | Monitor air quality continuously | ★★★☆☆ | $100–$350 | Easy |
| 10 | Schedule HVAC maintenance | ★★★★☆ | $100–$200/year | Easy |
The Connection Between IAQ and Energy Efficiency
There's a real tension between IAQ and energy efficiency. Tighter homes save energy but trap pollutants. More ventilation improves air quality but increases energy costs. Here's how to balance both.
The modern solution is mechanical ventilation with energy recovery. An ERV or HRV provides controlled fresh air exchange while recovering 70–85% of the energy from exhaust air. The annual operating cost is typically $50–$120 in electricity — far less than the energy penalty of opening windows.
| Ventilation Strategy | IAQ Impact | Energy Impact | Annual Cost |
|---|---|---|---|
| No mechanical ventilation | Poor | Lowest energy | $0 |
| Opening windows (1 hr/day) | Moderate | High energy loss | $200–$600 (HVAC penalty) |
| Exhaust-only fans | Fair | Moderate energy loss | $30–$80 |
| Supply ventilation | Good | Moderate energy loss | $40–$100 |
| ERV/HRV balanced | Excellent | Minimal energy loss | $50–$120 |
Real-World Example: Energy Recovery Ventilation Payback A homeowner in Minneapolis installed a Broan AI Series 200 CFM ERV for $3,200 (installed). Before installation, bedroom CO2 averaged 2,200 ppm overnight. After installation, CO2 stayed below 800 ppm. The ERV's heat recovery efficiency of 82% meant the additional heating cost was only $65/year versus an estimated $480/year if they'd achieved the same ventilation by opening windows. ROI on comfort and health was immediate; energy payback versus exhaust-only ventilation was approximately 8 years.
Special IAQ Situations
New Construction and Renovation
New homes and freshly renovated spaces have the highest VOC and formaldehyde levels. Off-gassing is most intense in the first 6–12 months and can continue at lower levels for 3–5 years.
Best practices: Request low-VOC materials during construction, run the HVAC system with MERV-13 filters continuously for the first 3 months, increase ventilation rates during this period, and consider an air purifier with activated carbon for VOC absorption.
Wildfire Smoke Events
Wildfire smoke sends outdoor PM2.5 to hazardous levels (200+ µg/m³), and this infiltrates homes rapidly. During smoke events, your home becomes a shelter — but only if you manage it properly.
Best practices: Close all windows and doors, run HVAC in recirculate mode with MERV-13 filters, run portable HEPA air purifiers, avoid cooking and other PM2.5-generating activities, and seal any obvious air leaks temporarily.
Allergy and Asthma Management
For allergy and asthma sufferers, IAQ management is medical treatment. The American College of Allergy, Asthma & Immunology identifies indoor allergens as a primary trigger for 60–80% of asthma patients.
Key interventions: HEPA air purification, MERV-13+ HVAC filtration, allergen-proof bedding covers, humidity control (40–50% RH to suppress dust mites and mold), and regular HVAC maintenance.
Key Takeaways
- Indoor air is 2–5× more polluted than outdoor air — and you spend 90% of your time indoors
- The six pollutants to track: PM2.5, VOCs, CO2, CO, radon, and biological contaminants
- A MERV-13 HVAC filter is the single highest-impact upgrade for most homes
- CO2 monitoring reveals whether your ventilation is adequate — target below 800 ppm
- Test for radon regardless of your location — it's the #2 cause of lung cancer
- Humidity between 40–50% RH suppresses mold, dust mites, and bacteria simultaneously
- Balanced ventilation (ERV/HRV) solves the IAQ vs. energy efficiency tradeoff
- Cooking is the #1 daily source of PM2.5 — always use a vented range hood
- Invest in a multi-parameter air quality monitor and track data for at least 2 weeks before making decisions
- Professional IAQ testing makes sense for persistent symptoms, home purchases, and legal documentation
Frequently Asked Questions
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