Some National Parks' Air Worse Than New York City's

Two national parks on opposite sides of the country were found to have air quality levels worse than such major cities as New York City and Washington, DC. For Sequoia, the combined pollution of Los Angeles and the San Joaquin Valley obscures views and triggers asthma in visitors. While a natural blue haze may have given the Great Smoky Mountains its name, a new kind of smoke - this time from power plants and heavy industry to the north and west - has caused the natural park to violate ozone standards set by the EPA.