| With the rapid development of industrialization and urbanization in Pearl River Delta, the pollution from vehicular particulate matter is increasing in urban areas. Road dusts are one of the two major sink of vehicular particles and other sourced dusts. On the other hand, road dusts also serve as the source to the pollutions of atmospheric aerosol and of the urban land-surface water and sediments. However, the study on the organic pollutants in the road dusts and related dusts is very limited. In this dissertation, the road and street dusts, gully sediments and tunnel ceiling dusts from Guangzhou and Hong Kong are fully and systematically investigated in term of abundance, composition and distribution of organic pollutants. The results indicate that the vehicle-emitted particles are the major source of organic pollutants in these dusts. In general, the characteristics of organic pollutants in these dusts from both cities are comparable but there also are significant differences between these two cities. These discriminations in road dusts from Hong Kong and Guangzhou suggest that road dusts and related dusts can be used as new indication system for assessing the environmental impact of vehicular exhaust on Pearl River Delta region. So, the following major points can be drawn from this study:1. The amount of extractable organic matter in road dusts, gully sediments and tunnel ceiling dusts from Hong Kong are significantly higher than that from Guangzhou. However, the relative distribution of organic hydrocarbon compositions in these dusts from both cities is comparable. According to the amount of the total extracts in the road dusts and gully sediments from Guangzhou, these dusts are categorized to three types: the total extract in road dusts is higher than, lower than and equal to that in gully sediments. While for Hong Kong's dust samples, the amounts of extracts in all road dusts are uniformly higher than that in gully sediments. These differences are mainly attributed to the heavily input of dusts from construction & transportation related activities as well as dry deposition from air in Guangzhou, which diluted the concentration of particle from vehicular emission.2. The difference in total extracts between tunnel ceiling dusts from the two cities mainly caused by the difference in their asphaltene contents. This difference may not only result from the difference in the quality and types of fuels used in two cities, but also attribute to the chronic weathering process since the Hong Kong tunnel has a much longer history than that of Tunnel in Guangzhou. The concentration of extracts in the ceiling dust from south-driving tunnels in both citiesis also significantly higher than that from north-driving tunnels. Coincidently, this difference is also mainly caused by the difference in the asphaltene content. This suggests that south-driving tunnel is relatively different from north-driving tunnel in ventilation. The findings are of active significance in engineering3. The distribution of n-alkanes in road dusts and gully sediments from Guangzhou can be divided into three patterns: front-peaked, tabled and isolated-peaked, while the patterns of n-alkanes in these dusts from Hong Kong are mainly front-peaked, rear-peaked, bimodal and fish-boned shaped. Aliphatic hydrocarbons are also characterized by unimodal (high boiling point) and bimodal (high or low boiling point) UCM for road dusts and gully sediments from Guangzhou, while only unimodal (high boiling point) UCM for road dusts and gully sediments from Hong Kong.4. The low ring triterpanes and hopanes are dominated by C tricyclic triterpanes and Csoccp hopane in tunnel ceiling dusts, road dusts and gully sediments from Guangzhou, respectively; while these dusts from Hong Kong are featured by dominating 24 tetracyclic triterpanes and 290 hopane. Gammacerane is abundant in tunnel ceiling dusts, road, dusts and gully sediments in Guangzhou city. The regular steranes in these dusts from Guangzhou are in the order of C29>C27>C28 which discriminated fro...
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