Of the energy systems considered, only coal technologies will produce primary and secondary atmospheric particles. HLLV launches associated with the SPS may produce small amounts of secondary particles, and these emissions may contribute slightly to regional climatic modification. The contribution of coal-combustion particles to any global warming or cooling should be small. Table 2 shows that the primary particulate emissions from coal-fired utilities constitute a very small fraction of total particulate emissions in the U.S. However the contribution of coal combustion to secondary particulate loadings by emission of S0x and N0x may be more important than the emission of primary particles, but the increasing use of emission control devices should limit these impacts. CO2 Impacts Gaseous CO2 is transparent to incoming solar radiation, but is a strong absorber of terrestrial radiation. Hence, an increase in atmospheric CO2 can produce an increase of absorbed terrestrial radiation in the troposphere, which is the portion of the atmosphere that is below the stratosphere and extends 10 to 15 kilometers from the earth's surface. The net effect has been shown to be tropospheric warming and a slight stratospheric cooling. Table 2. Annual Primary Particulate Emissions from U.S. Coal-Fired Utilities Compared with Annual Particulate Emissions from All Sources
RkJQdWJsaXNoZXIy MTU5NjU0Mg==