How do you measure indoor air quality?

The quality of the air inside your building can be a determining factor of occupant health and comfort. But how can you tell if you have poor indoor air quality? Here are some ways that indoor air quality is measured:

  • Humidity Sensors
  • CO₂ Sensors
  • Minimum Efficiency Reporting Values (MERV) Rating for Filters

Humidity Sensors

Humidity is an important standard for good indoor environments. It can be measured using a humidity sensor. Humidity sensors detect and measure the amount of water vapor in the air. Relative humidity is the measurement that is used to determine how comfortable a space is. Relative humidity takes into account both the amount of moisture in the air and the temperature. It is typically reported as a percentage. Occupants are most comfortable with relative humidity at 40-60%.

CO₂ Sensors

The level of carbon dioxide (CO₂) in the air is a key indicator of indoor environmental quality. Humans inhale oxygen and exhale CO₂. If CO₂ levels are too high, then occupants have difficulty concentrating because they can’t access enough oxygen. Levels of carbon dioxide are measured with a CO₂ sensor. These sensors report CO₂ in parts per million (ppm). Typically, CO₂ levels should stay below 1,000 ppm to prevent cognitive impairment and keep buildings occupants healthy.

MERV Ratings

Air filters are essential components of building HVAC systems because they prevent dust and other particulate matter from flowing freely throughout a building. This prevents occupants from breathing in those air pollutants. Air filters are rated using Minimum Efficiency Reporting Values, or MERV Ratings. MERV ratings report an air filter’s ability to prevent particulate matter from entering a space. MERV ratings range from 1-16. Filters with a MERV rating of 16 can filter out the smallest particles. MERV ratings on filters are important to consider when ensuring air quality. As air flows through a building, small particles are carried with it. These can be particles of pollen, dust, mold, bacteria, and even viruses. They can have a significant negative impact on occupants if they are being breathed in and are not filtered out of the air. The average MERV rating on a standard air filter is 8 for a large building.

Measuring your indoor air quality is a good way to start understanding how comfortable and healthy your building is.

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