Low-cost indoor air pollution monitoring helps protect children’s health

University of Birmingham researchers have developed a low-cost means of measuring indoor air quality in schools—creating new opportunities to safeguard the health of young people.

The researchers installed air pollution sensors in three classrooms at a Cardiff high school, measuring particulate matter (PM), which is the most important pollutant for human health. The sensors allowed researchers to pinpoint the sources of air pollution within the classrooms and whether they came from inside or outside the room.

Sensor data showed that 93-98% of tiny PM₁ pollutants originated outside the building. This contribution decreased as particle size increased, with outdoor sources accounting for 74-89% of PM_2.5 and 19-40% of larger PM₁₀ particles respectively.

In addition to outdoor sources, they discovered that differences in classroom PM concentration related to differences in lesson activities and frequency, whether the room was carpeted or hard-floored, and the classroom’s location within the school.

Published in Indoor Air this is the first paper published by McCall MacBain Clean Air Fellows studying for the master’s degree in Air Pollution Management and Control at the University of Birmingham.

Co-author and Clean Air Fellow Owain Rose commented, “Indoor air quality is becoming one of the most important factors for public health, as people spend far more time indoors compared to outdoors. By combining low-cost air pollution sensors with algorithms to determine pollution source, we can understand the factors affecting indoor air quality within a typical UK school—measuring air pollution concentrations during a typical school week and subsequent holiday period.”

The researchers discovered PM levels remained within World Health Organization guidelines while students were in the building during school hours—with the dominant sources of PM₁ and PM_2.5 coming from outdoors, while PM₁₀ sources were mainly from indoor sources.

Co-author and Clean Air Fellow Catrin Rathbone commented, “Our approach is easily translated to other indoor locations worldwide and could be scaled due to its low cost. It would allow air quality management in locations crucial for the public health and educational outcomes of children.”

The high school studied is in an urban area of Cardiff and accommodates approximately 900 pupils, between the ages of 11 and 19. For the two-week study period, three optical particle counter (OPC) sensors were installed in a religious studies classroom, an English studies classroom, and a home economics classroom.

Air pollution is a significant global environmental challenge that endangers human health, especially among vulnerable populations like children.

Schools represent a significant microenvironment for exposure to air pollution during childhood. In the UK, children spend 14.1% of their total year in school, making healthy indoor air quality within school environments vital for safeguarding their health.

Professor Francis Pope, from the University of Birmingham, commented, “The University of Birmingham is passionate about clean air—we’re at the forefront of research on the causes and effects of air pollution upon human health across the UK and around the globe.”

Imogen Martineau from the Clean Air Fund stated, “It has been amazing to see the success of the first Clean Air Fellow cohort. Owain and Catrin have been amazing ambassadors, and it is great to see them continuing their clean air journeys through taking jobs with leading environmental consultancies that specialize in air quality.”