Whilst showing a resident how to use a particulate air quality monitor, he told me that he would “never walk in Beech Street Tunnel again”. This statement was based on his involvement in Science in the City, a citizen science project that we are currently running to support communities to measure and map air quality. Based on the data gathered by the local community, between October 2013 and February 2014, this particular resident decided that there are cleaner, ‘healthier‘ and less polluted routes he could take to and from his home. When we at Mapping for Change are asked what impact our work has, or how involving non-professional scientists in community based scientific research makes a difference – I guess here’s the answer! This chap might even live an extra few years – who knows!!