When I talk to people about air pollution sources they normally blame the nearest busy road. In new research, 16,000 people were asked where they thought air pollution came from, revealing some important misunderstandings. Respondents from seven European countries were asked to pick the two main sources of air pollution. Top choices everywhere were industry and traffic. However, the reality is very different. Despite being in the top two, industry was responsible for less than 10% of the particle pollution measured in each country. This reflects decades of controls on the pollution that factories can dispose of up their chimneys. The top source of particle pollution breathed in six out of the seven countries, including the UK, was agriculture. This is frequently overlooked since agriculture emits little particle pollution directly. However, the ammonia from livestock and fertiliser reacts in the atmosphere to produce the smogs that plague Europe each spring. Home heating was also ranked low in people’s perception, but it is an important source in all the seven countries, especially in Italy as a result of wood burning, and in Poland where many homes are warmed by coal stoves. The researchers concluded that more dialogue between scientists, the public and politicians is needed to produce better policies to control air pollution.