Environmental policy of the United States Environmental Protection Agency, were people with a history of opposition to the agency they were named to head. Since the environmental movement of the 1970s, the nature of environmental issues has changed. While the initial emphasis was on conventional air and water pollutants, which were the most obvious and easily measurable problems, newer issues are long-term problems that are not easily discernible and can be surrounded by controversy. Acid deposition, in the form of acid rain and dry deposition, is the result of sulfur and nitrogen dioxide being emitted into the air, traveling and landing in a different place, and
Sulfur dioxide is made when sulfur combines with oxygen. The method of converting sulfur dioxide to sulfuric acid is called the contact process. Several billion kilograms are produced annually for this purpose. Sulfur dioxide is sometimes used as a preservative for dried apricots, dried figs, and other dried fruits, owing to its antimicrobial properties, and is called E220 when used in this way in Europe. As a preservative, it maintains the colorful appearance of the fruit and prevents rotting. It is also added to sulfured molasses. Sulfur dioxide was first used in winemaking by the Romans, when they discovered that burning sulfur