Which source is currently the primary contributor to sulfur dioxide emissions?

The primary contributor to sulfur dioxide emissions is coal burning power plants. This is largely due to the combustion of coal, which contains significant amounts of sulfur. When coal is burned for electricity generation, it releases sulfur dioxide into the atmosphere, contributing to air pollution and various environmental issues, such as acid rain and respiratory problems in humans.

In contrast, natural gas power plants produce significantly lower sulfur dioxide emissions because natural gas contains much less sulfur than coal. Solar energy installations and nuclear reactors do not emit sulfur dioxide during operation, making them cleaner alternatives in terms of this particular pollutant. These factors position coal combustion as the dominant source of sulfur dioxide emissions among the options provided.