tailieunhanh - Air pollution from ships: Bellona Foundation
Trees absorb pollutants through the same process they take up nutrients, . stomata (pores on the surface of the leaf), roots and root hairs. Additional pollution is removed by capture on their leaf/needle and bark surfaces. Taylor and Constable (1994) estimated for SO2 and O3 that 70% and 80% of the pollution absorbed is internal to the leaf. For particulates, the main wet absorption route is through tree roots (Broadmeadow and Freer-Smith, 1996), whereas the main dry absorption route is through deposition on leaf and bark surfaces. Occult deposition is also difficult to measure and may only be important in. | Increasing emissions Shipping is a major cause of harmful air pollution in Europe and by 2020 shipping emissions of SO2 and NOx could exceed the emissions of these pollutants from all other sources in the EU. This pollution must be reduced dramatically to protect health and the environment and to make shipping a more sustainable form of transport. Technical measures exist that could cut the level of pollution from ships by at least 80-90 per cent and doing so would be much cheaper than cutting the same amount of pollution from land-based sources. While pollutant emissions from land-based sources are gradually coming down those from shipping show a continuous increase. Emissions from ships engaged in international trade in the seas surrounding Europe the Baltic Sea the North Sea the north-eastern part of the Atlantic the Mediterranean and the Black Sea were estimated at million tonnes of sulphur dioxide SO2 million tonnes of nitrogen oxides NOx and 250 000 tonnes of particulate matter PM a year in 2000. Under a business-as-usual scenario it is expected that shipping emissions of SO2 and NOx will increase by 40 50 per cent between the year 2000 and 2020. By 2020 the emissions from international shipping around Europe are expected to equal or even surpass the total from all land-based sources in the 27 EU member states combined see Figures 1 and 2 . It should be noted that these figures high as they are refer only to ships in international trade. They do not include emissions from shipping in countries internal waterways or from ships plying harbours in the same country which are given in the domestic statistics of each country. However if the recent international agreement see pp. 4 5 on new SO2 and NOx emission standards is implemented by 2020 emissions of SO2 should come down significantly and those of NOx will not increase as much as previously anticipated. 12 000 10 000 8 000 6 000 4 000 2 000 0 15 000 12 000 9 000 6 000 3 000 0 Figure 1 Emissions of SO2
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