Wood heating is reintroducing lead into the air of local communities and homes, a systematic investigation by academics has found. Overwhelming evidence of lead’s neurotoxicity meant the metal was banned as an additive in petrol more than 25 years ago. The research by academics from the University of Massachusetts Amherst began by analysing samples of particle pollution from five suburban and rural towns in the north-east US. They looked for tiny particles of potassium that are given off when wood is burned and also particles containing lead. Samples from seven winters revealed associations between potassium and lead. When there were more wood burning particles in a daily sample, there was more lead in the air, with clear straight-line relationships in four of the five towns.…