Even coal-burning has become dramatically cleaner over the last 200 years. A simple technical fix added to coal plants in developed nations after 1950 reduced dangerous particulate matter by 99 percent. High-temperature coal plants are nearly as clean as natural gas plants, save for their higher carbon emissions. Natural gas is still, as a rule, superior to coal, for inherently physical reasons. But on the question of air pollution, the extent to which coal plants have become far cleaner is remarkable.
