Indoor Air Quality Monitoring: What to Measure and Why It Matters

Indoor Air Quality Monitoring: What to Measure and Why It Matters
Tips & Tricks

Indoor Air Quality Monitoring: What to Measure and Why It Matters

October 11, 2025

Why Indoor Air Quality Matters

We spend 90% of our time indoors, yet indoor air can be 2-5 times more polluted than outdoor air. From VOCs off-gassing from furniture to CO2 building up in bedrooms overnight, the air in your home directly impacts your health, sleep quality, and cognitive function.

Smart air quality monitors make the invisible visible, letting you take action before problems affect your wellbeing.

Key Air Quality Metrics

Carbon Dioxide (CO2)

High CO2 indicates poor ventilation and correlates with drowsiness and reduced cognitive performance:

  • Outdoor: ~420 ppm
  • Good indoor: Under 800 ppm
  • Moderate: 800-1000 ppm
  • Poor: Over 1000 ppm
  • Action needed: Over 1500 ppm

Particulate Matter (PM2.5)

Fine particles that penetrate deep into lungs. Sources include cooking, candles, outdoor pollution, and dust:

  • Good: 0-12 µg/m³
  • Moderate: 12-35 µg/m³
  • Unhealthy for sensitive: 35-55 µg/m³
  • Unhealthy: Over 55 µg/m³

VOCs (Volatile Organic Compounds)

Gases from paints, cleaners, furniture, and building materials. Measured in ppb or as an index:

  • New furniture and flooring are major sources
  • Cleaning products cause temporary spikes
  • Poor ventilation allows accumulation

Temperature and Humidity

These foundational metrics affect comfort and health:

  • Ideal temperature: 68-72°F (20-22°C)
  • Ideal humidity: 30-50% relative humidity
  • Below 30%: Dry skin, static, respiratory irritation
  • Above 50%: Mold risk, dust mite proliferation

Recommended Air Quality Monitors

Best Overall: Airthings View Plus

Measures CO2, PM2.5, VOCs, temperature, humidity, radon (bonus), and air pressure. Excellent app with trends and insights. Battery-powered with optional plug-in.

Best Budget: IKEA VINDSTYRKA

Surprisingly capable for the price. Measures PM2.5, VOCs, temperature, and humidity. Integrates with IKEA smart home and Matter.

Best for HomeKit: Eve Room

CO2, VOCs, temperature, and humidity with full HomeKit integration. Triggers automations based on readings.

Best for Detail: Awair Element

CO2, PM2.5, VOCs, temperature, and humidity with excellent data visualization and actionable recommendations.

Strategic Placement

Priority Rooms

  1. Bedroom: CO2 builds up overnight, affecting sleep quality
  2. Living room: Where you spend most awake time
  3. Home office: CO2 affects concentration and productivity
  4. Kitchen: Cooking generates significant PM2.5

Placement Tips

  • Mount at breathing height (3-5 feet)
  • Avoid direct sunlight and heat sources
  • Keep away from windows and vents
  • Allow air circulation around the sensor

Automation Ideas

Ventilation Control

If you have smart HVAC or fan controls:

  • When CO2 exceeds 1000 ppm, turn on ventilation
  • When PM2.5 is high, increase HVAC filtration
  • When outdoor AQI is good and indoor is poor, prompt to open windows

Air Purifier Automation

Smart plugs can control non-smart purifiers:

  • Turn on purifier when PM2.5 exceeds threshold
  • Run purifier on schedule during cooking hours
  • Turn off when levels return to normal

Humidifier/Dehumidifier Control

  • Activate humidifier when humidity drops below 30%
  • Turn off humidifier when humidity reaches 45%
  • Alert when humidity exceeds 60% (mold risk)

Improving Your Air Quality

Reduce CO2

  • Open windows regularly, even briefly in winter
  • Run bathroom exhaust fans longer
  • Add plants (though impact is modest)
  • Upgrade HVAC to increase fresh air intake

Reduce PM2.5

  • Use range hood when cooking
  • Avoid burning candles and incense
  • Run a HEPA air purifier
  • Vacuum with HEPA filtration
  • Change HVAC filters regularly

Reduce VOCs

  • Choose low-VOC paints and finishes
  • Let new furniture off-gas in garage first
  • Use natural cleaning products
  • Increase ventilation after using chemicals

Understanding Your Data

After a week of monitoring, you'll notice patterns:

  • Morning CO2 peak: Overnight bedroom buildup
  • Cooking PM2.5 spikes: Especially with gas stoves or high-heat cooking
  • Evening VOC rise: Cleaning products and personal care
  • Humidity drops: Winter heating dries indoor air

Use these patterns to time your interventions - ventilate before bed, run purifiers during cooking, humidify during heating season.

The Bottom Line

Air quality monitoring transforms an abstract concern into actionable data. Start with one monitor in your most-used room, learn your baseline, and take targeted action to improve the air you breathe.

Explore our complete guide to air quality monitors to find the right sensor for your home.