Poor air quality in metros can discourage riders, risk the safety of staff, and attract negative media attention. The Air Quality study examined how COMET metros monitor and manage air quality in their systems. It is focused on underground stations and onboard trains where pollutants can accumulate.
The report outlined the strategies metros have used to improve indoor air quality, including strategies that prevent emission of pollutants, reduce pollution concentration, and keep customers away from poor air quality. The study summarised the key recommendations to metros based on good practices identified from 30 metro organisations.