Evotech marks Clean Air Day 2023

15 June 2023

Evotech is marking this year’s National Clean Air Day (CAD) through its continued support to indoor air quality in local schools and the promotion of its #CleanAirSchools CO2 report which highlights poor ventilation in schools. 

The theme of this year’s CAD #CleanAirDay on June 15th is ‘Clean up our air to look after your mind’ which is designed to draw attention to the impact poor air quality can have on mental health as well as physical well-being. 

Evotech’s air quality division has launched the report after a year long study into classroom CO2 levels at five Calderdale schools. 

The pandemic shone a spotlight on the role of ventilation in making indoor spaces safer and healthier and England’s chief medical officer Professor Chris Whitty subsequently called for IAQ monitoring to become ‘standard practice’. 

Today Evotech is reinforcing its message to schools about how they can act positively to improve occupant comfort, health, and well-being by improving air quality and ventilation. However, many schools have difficulty improving ventilation through the age and fabric of their buildings. 

Fifty Nine percent of English state schools were built before the 1980s and by design have limited energy and thermal efficiency. Most classrooms also have high occupancy levels which can cause CO2 levels to rise rapidly, resulting in stale air and high virus transmission risks. And, according to the DfE’s Condition of School Buildings Survey 2021, the estimated cost of remedial repairs to the 22,031 state schools, in England alone, is £11.4 billion. 

The highest recorded CO2 reading of 5,966ppm (parts per million), over the school year (excluding weekends, holidays and lunchtimes) was 4,466ppm above DfE guidelines of 1,500ppm. However, the average classroom CO2 reading across all classrooms in the five schools over the whole academic year was 959ppm, which as a stand-alone figure looks fine, but the total number of hours spent over 1,500ppm was 4,846 which is far from ideal. 


The Evotech team is currently analysing levels of particulate matter at the schools with its next report due later this year and wants to step up pressure on the government to be more ambitious in its targets for reducing air pollution, which currently lags behind the latest WHO Air Quality Guidelines (September 2021). For example: the Environment Act 2021 in secondary legislation sets a concentration target for fine particulate matter (PM2.5) of 10 µg/m3 by 2040 against a WHO target of 5 µg/m3. Experts have stated that there is no safe level of particulate matter and that the health risks of exposure to even low levels of PM2.5 can be serious.


Click here to download the full report on Classroom CO2 Levels