... Weightings were calculated from straight-line measurement of the length of each country's coastline bordering the sea area in question. The weighted average was then calculated as the sum of: {[externality ... applied in the future.External costs of air pollution vary according to a variety of environmental factors, including overall levels of pollution, geographic location of emission sources, height of ... widespread in Europe, with particular hot-spots in a few countries, such as the Netherlands. The most visible effect is one of reducing the viability of rarer species of plant, allowing other species,...