Atmos
The air around you. Decoded.

Indoor Air Estimation

Understanding how we estimate the air quality inside your spaces

Important: Not Medical Advice

Our indoor air quality estimates are for informational purposes only and should not be considered medical advice. These are estimates based on scientific models and questionnaire responses. Always consult healthcare professionals for medical concerns related to air quality.

How Indoor Air Estimation Works

Indoor air quality is complex and influenced by many factors. We use a scientific approach combining outdoor air quality data with building characteristics to estimate indoor conditions.

Our Estimation Model

We calculate indoor air quality using a multi-factor model that considers:

1

Outdoor Air Quality

The starting point for all calculations. Outdoor pollutants infiltrate indoor spaces through ventilation, doors, windows, and building envelope leaks.

2

Building Type & Age

Different building types have different infiltration rates. Modern buildings are typically more airtight than older structures. We adjust estimates based on your building's characteristics.

3

Ventilation System

Air conditioning, heating systems, and mechanical ventilation significantly impact indoor air quality. HVAC systems with filters can reduce pollutant levels by 20-60%.

4

Air Purification

Air purifiers with HEPA filters can dramatically improve indoor air quality. We account for purifier presence and effectiveness in our calculations.

5

Window Status

Open windows increase air exchange with outdoors. When outdoor air quality is poor, keeping windows closed helps maintain better indoor conditions.

6

Indoor Sources

Activities like cooking, smoking, or burning candles add pollutants. We adjust estimates when you indicate these activities occur in your space.

The Calculation Formula

Our model uses a penetration factor approach based on EPA and research guidelines:

Indoor PM2.5 = Outdoor PM2.5 × Infiltration Factor × (1 - Filter Efficiency) + Indoor Sources

Infiltration factors typically range from 0.2 to 0.8 depending on building characteristics and ventilation.

Factors That Affect Accuracy

Indoor air quality estimates may vary significantly from actual conditions based on several factors:

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Ventilation Variability

The actual ventilation rate in your space can vary greatly based on HVAC operation, weather conditions, and building usage. Our estimates assume typical ventilation patterns.

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Building Characteristics

Every building is unique. Age, construction quality, maintenance, and retrofits all affect air infiltration rates. We use standard assumptions that may not perfectly match your specific building.

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Indoor Activities

Cooking, cleaning products, furniture off-gassing, and occupant activities can significantly impact indoor air quality in ways our model cannot fully predict.

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Location Within Building

Air quality can vary between rooms and floors. Areas near windows, kitchens, or high-traffic zones may have different conditions than our general estimate.

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Filter Maintenance

HVAC filter effectiveness degrades over time. Dirty or clogged filters provide less protection than clean ones, which our model assumes are well-maintained.

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Temperature & Humidity

Environmental conditions affect pollutant behavior and infiltration rates. Extreme temperatures or humidity levels can impact accuracy.

How to Get More Accurate Estimates

You can improve the accuracy of our indoor air quality estimates by providing detailed information about your spaces:

📝Complete the Questionnaire

Fill out the detailed questionnaire about your home, office, and other indoor spaces. Include:

  • Building age and type
  • HVAC system details
  • Air purifier presence
  • Typical window usage

🔄Keep Information Updated

Update your space details when conditions change:

  • New air purifier installed
  • HVAC system upgraded
  • Seasonal window habits change
  • Building renovations completed

📊Use Actual Monitors

For the most accurate readings, consider purchasing an indoor air quality monitor:

  • Real-time measurements, not estimates
  • Detect room-specific variations
  • Monitor indoor sources
  • Validate our estimates

💡Understand Limitations

Recognize when estimates may be less reliable:

  • During active cooking or cleaning
  • In very old or unique buildings
  • With significant indoor sources
  • When outdoor conditions change rapidly

Scientific Basis

Our estimation methodology is based on peer-reviewed research and guidelines from leading environmental health organizations:

  • 📚EPA Indoor Air Quality Guidelines - Standards for indoor/outdoor air quality relationships and infiltration factors
  • 📚ASHRAE Standards 62.1 & 62.2 - Ventilation and acceptable indoor air quality in residential and commercial buildings
  • 📚WHO Air Quality Guidelines - Health-based air quality standards and exposure assessment methods
  • 📚Lawrence Berkeley National Laboratory Research - Building air infiltration and ventilation effectiveness studies

While our model is scientifically grounded, it provides estimates, not measurements. Individual results may vary based on specific conditions.

Ready to Estimate Your Indoor Air Quality?

Fill out the questionnaire to get personalized indoor air quality estimates for your spaces.

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