What is carbon dioxide?

CO2 is a molecule of gas that consists of two oxygen atoms bonded to a single carbon atom.  It is commonly measured in parts per million (ppm) and is present in the atmosphere at approximately 300-500 parts per million.

Where does carbon dioxide come from?

Carbon dioxide is a common by-product of most organic processes.  It is generated when fuels are burned (petroleum, natural gas, wood, coal, etc.) and when animals breathe.  CO2 is also used in some manufacturing and food production industries (breweries and specialty indoor gardening).

Why is testing carbon dioxide useful?

We often use carbon dioxide levels as a benchmark indicator for ventilation in occupied spaces.  As humans generally exhale 35,000-50,000 ppm of CO2 in each breath, it can be an easy gas to measure and calculate a percentage of outside air.  We also can measure carbon dioxide levels in manufacturing facilities, green-houses, and indoor gardening operations.

Is carbon dioxide a health risk?

The occupational safety standard for CO2 exposure is time-weighted 5,000 ppm over an eight hour workday.  This level is very unlikely to ever occur outside of a specialty manufacturing facility or confined entry area, but lower levels may also cause some minor irritation and concerns.  At levels typical to occupied environments carbon dioxide is not a specific health risk, but levels above 1,000 ppm have been linked to symptoms such as lethargy and a decrease in worker productivity.

How do we test for carbon dioxide?

We use a variety of highly sensitive instruments to measure carbon dioxide, usually employing meters with NDIR (no drift infra-red) sensors.  The unit we use for our standard surveys is the TSI IAQ-CALC.  Additional equipment and long-term monitoring is available on a case-by-case basis.