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
Emission standard limit that sets thresholds above which a different type of emission control technology might be needed. While emission performance standards have been used to dictate limits for conventional pollutants such as oxides of nitrogen and oxides of sulphur (NOx and SOx), this regulatory technique may be used to regulate greenhouse gasses, particularly carbon dioxide (CO). In the US, this is given in pounds of carbon dioxide per megawatt-hour (lbs. CO/MWhr), and kilograms CO/MWhr elsewhere. In Canada, the Canadian Environmental Protection Act, 1999 (CEPA 1999) transfers the legislative authority for regulating emissions from on-road vehicles and engines to Environment Canada from