PM and gases should be improved to ensure that policy makers have accurate data on the amount and sources of pollution. A related paper by Bergin adds that high aerosol loadings decrease visual range and attenuate solar radiation, which may result in decreased crop yields in nearby rural areas.
Chow and Watson discuss problems with sampling techniques and the unreliability of conclusions based on incomplete data. They also note the relationships between combustion-related particulates, fugitive dust, and precursors. For example, it has been widely assumed that the source of much of the PM in Xian is the desert west of the city. However, sampling reveals that PM is mostly from combustion sources and local dust, such as unpaved roads and empty tracts of land. Based on this information, policy makers can now develop a more effective, locally based strategy for controlling pollution in Xian.
Natural gas is widely considered a viable replacement for coal, both for industry and home heating. But natural gas is expensive and not easily available in Chinese cities. In addition, further research will be necessary before vehicles that run on natural gas can be developed and before coal-fired heating boilers can be converted to natural gas.
Therefore, the Chinese government is committed both to the development of cleaner coal technology and to reducing the country’s dependence on coal. Coal combustion continues to be the largest contributor to air pollution in China, with particulates and SO2 causing the most significant problems. Although emissions of SO2 and particulates have declined in some major cities since the mid-1990s as a result of improved controls and the increased use of low-sulfur coals in the power sector, emissions of both pollutants must clearly be reduced further. However, it is not obvious how this can be done economically. China needs a full analysis of SO2 reduction under various control and policy strategies across various economic sectors. Xu et al. describe several control scenarios (with the required investments) for the power sector.
Xu et al. and Fritz both argue that coal will continue to be the dominant fuel for the next 50 years and that a variety of new technologies will be necessary to mitigate the negative environmental effects of coal consumption. These authors present a sober, realistic assessment of the difficulty of making a rapid transition to natural gas and renewable energy.
Based on the expectation that coal use will not only continue, but will even increase, Jin et al. make a strong case for the development and implementation of integrated gasification combined cycle (IGCC) with carbon dioxide (CO2) sequestration technology for power generation from coal. Fan and Yu provide a detailed look at the composition of the energy supply in China and urge local authorities to increase energy efficiency, use advanced technologies, and diversify the fuel mix.