Air Quality Measurement

UK law requires employers to make sure there’s adequate ventilation to supply fresh air to enclosed areas of the workplace.

The Covid-19 pandemic has made ventilation more important as it can reduce how much virus is in the air, which helps to reduce the risk from aerosol transmission. So adequate ventilation should be one of the factors considered in a Covid-19 risk assessment.

Ventilation is normally provided either naturally through air vents or open windows; or mechanically through ducts using fans to draw in fresh air.

As people exhale carbon dioxide (CO2), high concentrations of this in the air can indicate that the ventilation needs improving.

The amount of CO2 in the air is measured in parts per million (ppm). Outside air has a CO2 level of approximately 400ppm and indoors a CO2 value less than 800ppm is likely to indicate that the area is well ventilated.

Carlton Thermal Systems Ltd supplies a range of transmitters and sensors for monitoring CO2 levels between 400 and 5000 ppm. Other parameters measured can include temperature, humidity, atmospheric pressure, and volatile organic compounds (VOC) for a complete picture of indoor environment quality.

Detailed guidance on ventilation is published on the HSE site.