Do trees pollute the atmosphere? Tim RadfordThursday May 13, 2004The Guardian Yes, just as president Ronald Reagan said in 1981. "Trees cause more pollution than automobiles do," he opined. A little later, environmental scientists ruefully confirmed he was partially right. In hot weather, trees release volatile organic hydrocarbons including terpenes and isoprenes - two molecules linked to photochemical smog. In very hot weather, the production of these begins to accelerate. America's Great Smoky Mountains are supposed to take their name from the photochemical smog released by millions of hectares of hardwoods. This week Natural Environment Research Council scientists warned that...