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 refineries to produce sulfur as a byproduct. The Stretford process has also been used to remove sulfur from fuel. Redox processes using iron oxides can also be used, for example, Lo-Cat or Sulferox. Fuel additives such as calcium additives and magnesium carboxylate may be used in marine engines to lower the emission of sulfur dioxide gases into the atmosphere. As of 2006, China was the world's largest sulfur dioxide polluter, with 2005 emissions estimated to be . This amount represents a 27% increase since 2000, and is roughly comparable with U.S. emissions in 1980. Inhaling sulfur dioxide is associated with