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x. In atmospheric chemistry, NOx is shorthand for nitric oxide ( NO) and nitrogen dioxide ( NO2 ), the nitrogen oxides that are most relevant for air pollution. [1] [2] These gases contribute to the formation of smog and acid rain, as well as affecting tropospheric ozone . NOx gases are usually produced from the reaction between nitrogen and ...
Greenhouse gas emissions from wetlands of concern consist primarily of methane and nitrous oxide emissions. Wetlands are the largest natural source of atmospheric methane in the world, and are therefore a major area of concern with respect to climate change. [1] [2] [3] Wetlands account for approximately 20–30% of atmospheric methane through ...
Nitrogen dioxide is a reddish-brown gas with a pungent, acrid odor above 21.2 °C (70.2 °F; 294.3 K) and becomes a yellowish-brown liquid below 21.2 °C (70.2 °F; 294.3 K). It forms an equilibrium with its dimer, dinitrogen tetroxide ( N2O4 ), and converts almost entirely to N2O4 below −11.2 °C (11.8 °F; 261.9 K). [6]
The five most abundant greenhouse gases in Earth's atmosphere, listed in decreasing order of average global mole fraction, are: [5] [6] water vapor, carbon dioxide, methane, nitrous oxide, ozone. Other greenhouse gases of concern include chlorofluorocarbons (CFCs and HCFCs ), hydrofluorocarbons (HFCs), perfluorocarbons, SF. 3.
History Initial petition and initial denial. Section 202(a)(1) of the Clean Air Act requires the Administrator of the EPA to establish standards "applicable to the emission of any air pollutant from…new motor vehicles or new motor vehicle engines, which in [her] judgment cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare" (emphasis ...
Greenhouse gas monitoring is the direct measurement of greenhouse gas emissions and levels. There are several different methods of measuring carbon dioxide concentrations in the atmosphere, including infrared analyzing and manometry. Methane and nitrous oxide are measured by other instruments. Greenhouse gases are measured from space such as by ...
The United States produced 5.2 billion metric tons of carbon dioxide equivalent greenhouse gas (GHG) emissions in 2020, [5] the second largest in the world after greenhouse gas emissions by China and among the countries with the highest greenhouse gas emissions per person. In 2019 China is estimated to have emitted 27% of world GHG, followed by ...
Carbon dioxide (CO 2) is the main greenhouse gas resulting from human activities. It accounts for more than half of warming. Methane (CH 4) emissions have almost the same short-term impact. [5] Nitrous oxide (N 2 O) and fluorinated gases (F-gases) play a lesser role in comparison.