Draft Environmental Impact Report - East Bay Municipal Utility District

Estates Reservoir Replacement Draft Environmental Impact ReportGreenhouse Gasesin negative radiative forcing. The depletion of stratospheric ozone and its radiativeforcing was expected to reach a maximum in about 2000 before starting to recover,with detection of such recovery not expected to occur much before 2010. The pastincrease in tropospheric ozone, which is also a GHG, is estimated to provide the thirdlargest increase in direct radiative forcing since the pre-industrial era, behind CO 2 andCH 4 . (USEPA 2008)Halocarbons, Perfluorocarbons, and Sulfur Hexafluoride (SF 6 ) - Halocarbons are, forthe most part, man-made chemicals that have both direct and indirect radiative forcingeffects. Halocarbons that contain chlorine—CFCs, hydrochlorofluorocarbons (HCFCs),methyl chloroform, and carbon tetrachloride—and bromine—halons, methyl bromide,and hydrobromofluorocarbons (HBFCs)—result in stratospheric ozone depletion.Although CFCs and HCFCs include potent global warming gases, their net radiativeforcing effect on the atmosphere is reduced because they cause stratospheric ozonedepletion, which is itself an important GHG in addition to shielding the Earth fromharmful levels of ultraviolet radiation. (USEPA 2008)Carbon Monoxide (CO) - Carbon monoxide has an indirect radiative forcing effect byelevating concentrations of methane and tropospheric ozone. Carbon monoxide iscreated when carbon containing fuels are burned incompletely. (USEPA 2008)Nitrogen Oxides (NO x ) - The primary climate change effects of nitrogen oxides (i.e., NOand NO 2 ) are indirect and result from their role in promoting the formation of ozone inthe troposphere and, to a lesser degree, lower stratosphere, where it has positive radiativeforcing effects. Nitrogen oxides are created from lightning, soil microbial activity,biomass burning – both natural and anthropogenic fires – fuel combustion, and, in thestratosphere, from the photo-degradation of N 2 O). (USEPA 2008)Nonmethane Volatile Organic Compounds (NMVOC) - Nonmethane volatile organiccompounds (also referred to as VOC) include compounds such as ethane (C 2 H 4 ), propane(C 3 H 8 ), butane (C 4 H 10 ), and pentane (C 5 H 12 ). These compounds participate, along withNO X , in the formation of tropospheric ozone and other photochemical oxidants.NMVOCs are emitted primarily from transportation and industrial processes, as well asbiomass burning and non-industrial consumption of organic solvents. (USEPA 2008)Aerosols - Aerosols are extremely small particles or liquid droplets found in theatmosphere. They can be produced by natural events such as dust storms and volcanicactivity, or by anthropogenic processes such as fuel combustion and biomass burning.Aerosols are removed from the atmosphere relatively rapidly by precipitation. (USEPA2008)Various categories of aerosols exist, including naturally produced aerosols such as soildust, sea salt, and anthropogenically manufactured aerosols such as industrial dust andcarbonaceous aerosols from transportation, coal combustion, cement manufacturing,waste incineration, and biomass burning. The net effect of aerosols is believed toproduce a negative radiative forcing effect.sb09_001.doc 3-8.5 7/22/2009