As the effects of continuing wildfires in Canada spread to the United States, President Trump argued that the costs of air pollution should be added to the tariffs currently imposed on Canada, saying that it is the result of Canada's neglect of forest management. In the eastern province of Ontario, Canada, wildfires have been occurring one after another due to high temperatures and lightning strikes, and firefighting efforts are continuing, but air pollution from wildfire smoke is also spreading across the border to the United States.