Our overall air quality is better now than it was 30 years ago.
Part of this success is due to efforts by the coal-based electricity industry to reduce emissions.
Source: Coalition for Affordable and Reliable Energy

Coal is increasingly less polluting
Coal consumption trends to lower sulfur coal and sulfur dioxide emissions from U.S. coal-fired power plants have declined by more than 20% since 1970. This comes as a result of improved technology even as coal consumption for domestic electric power has almost tripled.
Source: Coalition for Affordable and Reliable Electricity

Clean coal technologies represent a new class of pollution control and power generating processes
These processes reduce air emissions and lower greenhouse gases to a fraction of the levels of conventional coal-burning plants. They also boost power plant efficiencies and release carbon gases in a form that can be prevented from entering the atmosphere.
Source: Department of Energy