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Greenhouse gas emissions from bioenergy can be low because when vegetation is harvested for bioenergy, new vegetation can grow that will absorb CO 2 from the air through photosynthesis. [2] After the biomass is harvested, energy ("bioenergy") is extracted in useful forms (electricity, heat, biofuels , etc.) as the biomass is utilized through ...
A biogenic substance is a product made by or of life forms. While the term originally was specific to metabolite compounds that had toxic effects on other organisms, [1] it has developed to encompass any constituents, secretions, and metabolites of plants or animals. [2] In context of molecular biology, biogenic substances are referred to as ...
In contrast, anthropogenic sources are caused by human activity. Some sources of a trace gas are biogenic processes, outgassing from solid Earth, ocean emissions, industrial emissions, and in situ formation. [1] A few examples of biogenic sources include photosynthesis, animal excrements, termites, rice paddies, and wetlands. Volcanoes are the ...
[9]: 2248 Subsequently, a pool is defined as "a reservoir in the Earth system where elements, such as carbon and nitrogen, reside in various chemical forms for a period of time". [ 9 ] : 2244 The United States Geological Survey (USGS) defines carbon sequestration as follows: "Carbon sequestration is the process of capturing and storing ...
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 added). [3]
[22] [23] Another human-caused source of carbon dioxide is cement production. The burning of fossil fuels and cement production are the main reasons for the increase in atmospheric CO 2 since the beginning of the industrial era. [10] Other human-caused changes in the atmospheric carbon cycle are due to anthropogenic changes to carbon reservoirs.
Methane emissions occur in all sectors of the natural gas industry, from drilling and production, through gathering and processing and transmission, to distribution. These emissions occur through normal operation, routine maintenance, fugitive leaks, system upsets, and venting of equipment.
Methanogenesis or biomethanation is the formation of methane coupled to energy conservation by microbes known as methanogens.It is the fourth and final stage of anaerobic digestion.