|| Checking for direct PDF access through Ovid
The type of energy system and industrial structure of urban areas is very important for the total amounts of Cu emitted. The total per capita emission for the New York area is estimated to be approximately 4 times larger than Stockholm municipality between 1900–1980. The latter was mainly the result of large differences in energy systems and industrial structure. Hydro-electric power and non fossil fuels were important energy sources for Stockholm while coal was a much more significant fuel for the New York area. Metal processing has characterised the industries of Stockholm while the New York area was a national centre for copper and petroleum refining as well as the chemical industry. In both cases the estimated Cu emissions from fuel combustion and industry decreased from 1900–1980. But in the case of consumption related emissions the time trends differ between the two urban areas. In Stockholm end use was the largest category of Cu emissions during the whole time period studied. In the New York area consumption related emissions became the largest source of Cu emission in the 1950s.