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This work is intended to provide a relatively simple tool for assessing the sources of atmospheric particles during pollution episodes. The main line of investigation is to examine the relationships, if any, between hourly average concentrations of PM10 and, where data are available, PM2.5 and the other, gaseous, pollutants monitored at sites in the UK's national monitoring network. Particles are a pollutant of especial interest as there is a considerable amount of evidence suggesting that they have significant adverse health effects. There is a growing body of evidence to suggest that there can be both chronic and acute effects. There is also evidence to suggest that particles can affect both the respiratory system and the cardiovascular system. Air pollution episodes are more likely to bring about acute effects but these can either result in people with respiratory conditions having to take extra medication or in increased hospital admissions or, in extreme cases, can lead to increased numbers of deaths in the period following an episode. There is considerable debate as to whether these deaths are advanced by a few days and are in groups of people who are already in a poor state of health (the "harvesting effect") or whether there are significant advances in deaths. A range of episodes are examined. These look at construction activities causing high concentrations of PM10, summer photochemical episodes, long range transport episodes involving secondary particles, industrial emissions causing elevated concentrations of PM10, both in the short term and over longer periods, a "Sahara Sand" episode and episodes involving emissions from road traffic in mid-winter. This figure shows a construction episode:
and this shows a long range transport episode:
The final three graphs illustrate a winter road traffic episode in Bristol. These illustrate the "Excess" or "Residual" concentrations of PM10, nitrogen dioxide and ozone during the episode. This represents the difference between the measured concentrations of these pollutants during the episode and the long term hourly average concentrations for each pollutant.
For more informtaion relating to Source apportionment of PM10 during air pollution episodes contact David Muir: david_muir@bristol-city.gov.uk Author: Dave Muir |
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