The way our cities are built, and how, or whether, they are shaped around transit, has a major effect – positively or negatively – on public health. Transport affects public health in many ways as transport emissions are a major source of air pollution. Air pollution contains harmful products like particulate matter, carbon monoxide, nitrogen oxide, and carcinogens. These are leading factors in asthma, respiratory illness, heart disease, low birth rates, and premature death. ITDP is working to improve health & safety for millions of people in cities all over the world with a host of programs that reduce air pollution, enhance road safety, and promote active living.