「エアロゾルの地球化学」によせて(<特集>エアロゾルの化学)

概要

論文の詳細を見る
Aerosol particles exist abundantly in the ambient atmosphere, where their diameters range from 〜10nm to > 10μm. The atmospheric particles directly reflect or absorb solar radiation, cooling or warming the earth surface. If the aerosol are enriched with ammonium sulfate and organic compounds, they scatter the radiation back to the space because of their white nature. In contrast, if the particles are enriched with black carbon, they absorb the radiation and warm the atmosphere. The direct effect of the aerosols on the radiation, therefore, largely depends on their chemical composition. Further, aerosols can act as cloud condensation nuclei (CCN) to form clouds, which indirectly control the radiation balance on the earth surface. This indirect effect of aerosols is also controlled by the chemical composition of aerosols and their hygroscopic properties. Both direct and indirect effects of atmospheric aerosols are significantly influenced by their chemical composition. Although these effects on the radiation are large enough to cancel out the warming effects of greenhouse gases emitted by human activities (IPCC, 2001; 2007), there are significant uncertainties in the estimates of the direct/indirect effects on the earth surface. The uncertainties are mainly caused from the incomplete understanding of chemical composition, spatial distributions and physico/chemical properties of aerosols in the atmosphere. Atmospheric aerosol particles contain inorganic and organic pollutants (e.g., sulfate, organic acids, etc.) that cause adverse effect on plants, animals as well as human health on a regional and global scale. Those chemical species are primarily emitted from the various sources and/or secondarily produced in the atmosphere by photochemical exidation of precursor compounds. For the last two decades, economical growth and industrial development have been significantly enhanced in the East Asian countries, especially in China. Consequently, atmospheric emissions of aerosol particles and their precursors (SO_x, NO_x, volatile organic compounds, etc.) have seriously increased in East Asia as a result of increased usage of fossil fuels (Akimoto, 2003). In addition to the increased sulfur emissions, a significant increase in the concentration of nitrogen oxides has been observed in the coastal China by the satellite observation from the space (Richter et al., 2005). In the western Pacific region, important international programs on atmospheric aerosols have been conducted for the past several years, including ACE-Asia project (Aerosol Characterization Experiment in Asian Pacific Region) (e.g., Huebert et al., 2003). Many Japanese scientists have joined to those programs and contributed to a progress in the aerosol chemistry in East Asia. In this special issue, we collected 6 papers focused on the Special Session on Geochemisty of Aerosols and Related Gases in the East Asia and Pacific Ocean region (7 oral and 10 poster presentations), which was held at the annual meeting of Geochemical Society of Japan (October 13-15, 2006, Tokyo). Six papers presented in this issue cover several topics on the water-soluble ions in the aerosols from Chinese mega-cities, semi-volatile aldehydes in Tokyo, organic tracers in Jeju Island, South Korea and Cape Hedo in Okinawa Island, long-range atmospheric transport of Chinese dusts over western Japan, and chemical composition of sea fogs as a scavenger of atmospheric particles over the western North Pacific. Although these topics are few examples of the aerosol studies that have been conducted in East Asia and the western North Pacific, these papers should be helpful to understand the current research subjects of aerosols and most recent outcomes from the aerosol programs in East Asia. We wish that this Special Issue of Geochemistry could act as useful media for the aerosol community and the new comers to this research field of atmospheric chemistry.
2007-12-28

「エアロゾルの地球化学」によせて(<特集>エアロゾルの化学)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク