In the fifth episode of the Envirohealth podcast, Carl spoke with Andrew Grieve about using apps, smartphones, and digital devices as communication and research tools for air pollution research. During such work, he has designed and developed several air quality apps, including LondonAir, CityAir (for the City of London), SarajevoAir (for the United Nations), Canairy (for the British Safety Council) cleanairroutes.london (for Cross River partnership) and Airwaze for a Ph.D. studentship.