According to research by the Environmental Protection Agency, New York is at the top of the ranking for air pollution. Most of the harmful substances are emitted into the atmosphere by cars, buses and construction vehicles. Thick smog often hangs over the city. Experts believe that if the situation does not change, residents will have to use respirators when going outside. The most difficult situation is in Manhattan. This is one of the most densely populated areas with heavy traffic. The incidence of cancer here is three times higher than the US average. This disease is associated with the presence of toxic particles in the atmosphere.