Improve air quality in public transportation | Science

Millions of people rely on urban public transport systems (1), which are essential for sustainable urban living. However, in vehicles and public transportation hubs around the world, air quality remains unregulated (2) and levels of air pollutants exceed those in ambient outdoor air (3–7), threatening the health of commuters and transit workers. Improving air quality in these contexts is essential to preserve the health of the population in increasingly urbanized societies.