The stratosphere is a layer of the atmosphere 9-31 miles above the Earth. Ozone in the stratosphere filters out harmful sun rays, including a type of sunlight called ultraviolet B, which has been linked to health and environmental damage. The heat content of subbituminous coal ranges from 16 to 24 million Btu per ton as received and averages about 18 million Btu per ton. Subbituminous coal, mined in the western coal fields, is used for generating electricity and space heating. A facility or equipment that switches, changes, or regulates, e.g., steps up or steps down, the electric voltage in utility power lines.
Voltage is stepped up where power is sent through long-distance transmission lines.
One of the elements present in varying quantities in coal which contributes to environmental degradation when coal is burned. Compliance'' coal, when burned, emits no more than 1.2 pounds of sulfur dioxide per million Btu. Some Appalachian and much Powder River Basin reserves are of compliance and low sulfur grades. A criteria air pollutant. Sulfur dioxide is a gas produced by burning coal, most notably in power plants.