This time in Book Club, we follow sustainability journalist Tim Smedley as he pursues one of humankind’s greatest challenges and looks at the dangers posed by air pollution. Intrigued by some casual facts and figures he’d stumbled across in a newspaper, Smedley investigated further, then decided to travel around the world to look at the factors affecting air quality in major cities. Along with examples of how air pollution occurs and some frightening statistics – some compiled from his own measurements using a hand-held air pollution monitor – he suggests practical ways individuals can make a tangible difference to the quality of air in their communities.