Internal combustion engine the atmosphere by the reaction of and volatile organic compounds in the presence of sunlight. Ground-level ozone is harmful to human health and the environment. Though the same chemical substance, ground-level ozone should not be confused with stratospheric ozone, or the ozone layer, which protects the earth from harmful ultraviolet rays. Carbon fuels contain sulfur and impurities that eventually produce sulfur monoxides (SO) and sulfur dioxide (SO) in the exhaust, which promotes acid rain. In the United States, nitrogen oxides, PM, carbon monoxide, sulphur dioxide, and ozone, are regulated as criteria air pollutants under the Clean Air Act to levels
Environmental standard that can be released into atmosphere in order to maintain air quality and human health and regulate the release of greenhouse gases such as carbon dioxide (CO), oxides of nitrogen and oxides of sulfur. The standards are established in two phases to stay up to date, with final projections aiming to collectively save Americans $1.7 trillion in fuel costs and reduce the amount of greenhouse gas emissions (GHG) by 6 billion metric tons. Similar to the ambient standards, individuals states may also tighten regulations. For example, California set their own emissions standards through the California Air Resources Board (CARB), and