University of Birmingham scientists have developed a new way of measuring, analysing, and mapping indoor air pollution that - in initial trials - has established a clear link between office occupancy, physical activity, and air quality.

Using radar-powered movement detectors and low-cost pollution sensors, researchers equipped office space in central Birmingham to monitor the number of people present and measure the kinetic energy they generated as they went about their work.

One of the most important, yet insufficiently studied, sources of indoor air pollution is particulate matter (PM) that is made airborne through occupants’ movements. Particulate matter trapped within carpeting, furniture, office equipment, and people’s clothes and shoes becomes airborne in indoor environments through human activity.

Publishing their findings in NPJ Climate and Atmospheric Science, the researchers found that weekday concentrations of inhalable particulate matter one-fifth the width of a human hair – known as PM10 – were up to four times higher during occupied periods than during unoccupied periods. Other pollutants studied – carbon dioxide (CO2) and total volatile organic compounds (TVOC) – also showed elevated levels on working days, up by 22% and 140% respectively.

When mapping indoor air pollution, occupied office periods averaged 13.7 µg/m³ PM₁₀, compared to 3.75 µg/m³ when empty. WHO’s annual PM₁₀ guideline is 15 µg/m³. CO₂ rose by 130 ppm to 584 ppm and TVOCs rose by 318 µg/m³ to 495 µg/m³ indoors.

The University of Birmingham team worked on the new system – installed in an open plan office area and a meeting room – with counterparts from Queen Mary University London and experts from Cundall, an independent, global sustainable engineering and design consultancy.

Co-author Francis Pope, Professor of Atmospheric Science at the University of Birmingham, said: “Government and industry are looking for evidence-based, low-cost methods to manage indoor pollution. Our study creates a new way of analysing and discussing indoor air quality that can be used immediately to help create better buildings for work, leisure and living.”

Read the full article about mapping indoor air pollution at University of Birmingham.