COMMON QUESTIONS
Why is Indoor Air Quality and Air Safety Important?
About Air Safety
When people gather in a closed or partially closed space, their exhaled CO2 (carbon dioxide) builds up in concentration along with particles, odors (perspiration), and germs. If someone is ill, their exhaled breath contains tiny aerosol droplets to which are attached bacteria or viruses such as flu and Covid. A healthy indoor environment is one where the ventilation system brings in fresh, filtered outside air while exhausting (removing, washing away) the contaminated room air. CO2 levels are low in outside air, so the if indoor CO2 levels are high, it indicates that outside air ventilation is so inadequate that occupants may be breathing in dangerous concentrations of germs.
Is CO2 Toxic?
CO2 is not directly toxic to breathe, but higher levels are associated with headaches and inattention. Car and truck drivers, to remain alert, should monitor the cabin concentration when heating or cooling with the vents closed.
What is a Safe Level of CO2?
Expert authorities (OSHA / ASHRAE) have established that indoor gatherings should maintain a CO2 concentration of no more than 1000 parts per million (ppm), or 0.1%. Between 1000 and 2000 ppm, air is becoming stuffy and somewhat contaminated with minor effects. Above 2000 ppm, studies show an increase in drowsiness, headaches, lowered concentration, and the likelihood of spreading viruses like colds and flu and Covid-19. The Personal Air Safety Reporter provides a colored light for each of these CO2 levels, green, yellow, or red, in addition to an accurate concentration in ppm.
What to do about Unsafe Air?
When you encounter an unsafe level of CO2, TAKE ACTION. In a car or truck cab, open a window or open the outside air vent. In a school or hospital, contact the building manager, show your Personal Air Safety Reporter, and suggest that the ventilation equipment be adjusted to increase outside air until the CO2 concentration level gets down into the green region below 1000 ppm.
How Accurate is the Personal Air Safety Reporter (PASR)?
Evergreen Telemetry uses state-of-the-art sensing technology and a sophisticated calibration method that is directly linked to the National Institute of Standards and Technology (NIST) in Washington, DC, as confirmed on the enclosed calibration certificate. Laboratory conditions allow precise control of CO2 levels and other environmental conditions. In practical applications, the user will observe minute-by-minute variations and differences between meters, because the levels of CO2 being detected are so very, very tiny. 1000 parts per million is only one tenth of one percent. The accuracy of the Reporter is expressed as 5% of the reading, plus 50 ppm. That means that if the actual CO2 level is 1000 PPM, one meter may read 950 and another meter may read 1050, and both would be considered accurate. PPM guidelines should be considered as broad ranges with fuzzy boundaries. It is not the purpose to distinguish between 999 ppm vs 1001 ppm, but between a solidly healthy 700 ppm vs a less desirable 1500 ppm vs a definitely unhealthy 2500 ppm.
