A recent study has found that keeping classroom windows closed is not an effective way to reduce air pollution in schools. The Schools’ Air quality Monitoring for Health and Education (SAMHE) project, led by Imperial College London, monitored air pollution in nearly 500 classrooms across the UK for an academic year.
The study found that days with high outdoor pollution led to higher pollution levels inside classrooms. Six per cent of school days had outdoor particle pollution above World Health Organization daily guidelines, but these days contributed 17 per cent of the annual classroom pollution.
Dr Alice Handy of the SAMHE team said: “Reducing ventilation will not stop outdoor PM2.5 entering classrooms. We saw high levels of particle pollution in classrooms during weekends around fireworks night when schools and classrooms were closed.” She emphasised the importance of ventilation for reducing carbon dioxide levels, which affect attention and infection risk.
The good news is that classrooms provided some protection, with average particle pollution 30 per cent lower than outdoors. Over the school year, about 80 per cent of classroom pollution came from outside. The study also tested air filters in 300 classrooms, which reduced particle pollution by 29 per cent compared with nearby schools, but outdoor air quality remained the main driver.
Dr Samuel Wood said: “We saw significant reductions, but outdoor air quality was still the leading driver of classroom particle pollution, even with filters installed. Air filters may mitigate some effects but are unlikely to remove them altogether.” The researchers called for continued initiatives such as no-idling zones and reducing fossil fuel use.
