Coal is the single biggest air polluter in the US. Union of Concerned Scientists (UCS), a US-based body suggests that 44% of the entire nation's electricity is generated via coal.
A typical (500 megawatt) coal plant burns 1.4 million tons of coal each year. As of 2012, there are 572 operational coal plants in the U.S. with an average capacity of 547 megawatts.
In fresh evidence about the dangers of coal pollution, a scientist said a switch to coal-fired power in a southern US state after a nuclear accident in 1979 led to a sharp fall in birthweight, a benchmark of health.
Coal plants also lead to the emission of other toxic gases into the environment such as nitrogen dioxide, mercury, sulfur dioxide and other particulate matter.
After the energy switch, the weight of newborns fell by 5.4 percent in Tennessee Valley counties that had the highest levels of air pollution from coal particles emitted by the replacement plants, the investigation found.
Birthweight reductions of just over five percent can result in illness, stunted growth and neurodevelopment problems later in life, earlier research has shown. They are also strongly linked to lower IQ and income.