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An emission inventory for fine particle aerosol carbon has been constructed for the Metropolitan Los Angeles area and compared to the results of ambient sampling. Information on the level of source activity, total aerosol emission rate, particle size and chemical composition was used to estimate the mass emission rate of particulate organic and elemental carbon in this urban area. It was found that carbonaceous particle emissions to the atmosphere arise from more than fifty classes of mobile and stationary air pollution sources. Emission data for elemental carbon at present contain significant uncertainties. Methods for verifying the consistency of carbonaceous aerosol emission inventories thus are important. Verification tests based on comparison of the ratio of organic carbon to elemental carbon and lead in source emissions versus that measured in the atmosphere were developed in this paper. Using these tests, excellent agreement was found between the emission inventory and results of ambient sampling in Los Angeles during January and February 1980.

Aerosol carbon concentrations have been measured under wintertime conditions at two sites in the Los Angeles basin. Samples were analyzed for total carbon by the Gamma Ray Analysis of Light Elements (GRALE) technique and for elemental carbon by reflectance. Total carbon concentrations at downtown Los Angeles averaged 24 µgm^(-3) and elemental carbon concentrations averaged 9 µgm^(-3) during the 7 am to 1 pm period. The light absorption efficiency of ambient elemental carbon particles was determined to be 11.9 + 0.9 m^2g^(-1), and it was estimated that light absorption by elemental carbon could account for up to 17% of total light extinction in downtown Los Angeles. Baseline conditions for elemental carbon concentrations in the Los Angeles area prior to the introduction of large numbers of diesel passenger cars into the vehicle fleet are established by these measurements. A method for reconstruction of a long time series of past historical air monitoring data on elemental carbon concentrations is described.

Aerosol carbon concentrations have been measured under wintertime conditions at two sites in the Los Angeles basin. Samples were analyzed for total carbon by the Gamma Ray Analysis of Light Elements (GRALE) technique and for elemental carbon by reflectance. Total carbon concentrations at downtown Los Angeles averaged 24 µgm^(-3) and elemental carbon concentrations averaged 9 µgm^(-3) during the 7 am to 1 pm period. The light absorption efficiency of ambient elemental carbon particles was determined to be 11.9 + 0.9 m^2g^(-1), and it was estimated that light absorption by elemental carbon could account for up to 17% of total light extinction in downtown Los Angeles. Baseline conditions for elemental carbon concentrations in the Los Angeles area prior to the introduction of large numbers of diesel passenger cars into the vehicle fleet are established by these measurements. A method for reconstruction of a long time series of past historical air monitoring data on elemental carbon concentrations is described.

The Rio Tinto copper mines in Spain, abandoned for 13 centuries after the major Roman operations came to an end, were rehabilitated by L. Wolters in 1725 and worked by his successors Samuel Tiquet (1727-1758), Francisco Thomas Sanz (1758-1783), the state (1783-1829) and the Marquis of Remisa (1829-1849). Production, metal recovery and fuel consumption figures are given for these periods and the dry and wet processes used for Cu extraction are discussed, as well as their long-term environmental effects. Ore consisted of chalcopyrite and pyrite with minor oxides and secondary sulphides. The dry processing route, established in 1747 and continued until artificial cementation was substituted in 1845, involved three phases of open-air calcining followed by smelting and refining stages. Wet processing by natural cementation involved precipiting Cu from acid mine drainage by passing the acid waters over a stoichiometric excess of iron fragments in a channel in the old Roman working of San Roque. Major environmental impacts included the clearing of forests for furnace fuel and the generation of acid rain, which leached nutrients from the ground and polluted both groundwater and surface water., The Rio Tinto copper mines in Spain, abandoned for 13 centuries after the major Roman operations came to an end, were rehabilitated by L. Wolters in 1725 and worked by his successors Samuel Tiquet (1727-1758), Francisco Thomas Sanz (1758-1783), the state (1783-1829) and the Marquis of Remisa (1829-1849). Production, metal recovery and fuel consumption figures are given for these periods and the dry and wet processes used for Cu extraction are discussed, as well as their long-term environmental effects. Ore consisted of chalcopyrite and pyrite with minor oxides and secondary sulphides. The dry processing route, established in 1747 and continued until artificial cementation was substituted in 1845, involved three phases of open-air calcining followed by smelting and refining stages. Wet processing by natural cementation involved precipiting Cu from acid mine drainage by passing the acid waters over a stoichiometric excess of iron fragments in a channel in the old Roman working of San Roque. Major environmental impacts included the clearing of forests for furnace fuel and the generation of acid rain, which leached nutrients from the ground and polluted both groundwater and surface water.