In order to protect the environment and human health from being harmed by air pollution, governments and organisations have been publishing standards and guideline values for pollutant emissions and ambient concentrations, as well as acts and regulations for enforcement. Consequently, various techniques have been developed for sampling and analysing ambient air, to ensure that the set standards and regulations are complied with. New legislation increasingly requires investment in environmental monitoring and pollution control that will deliver the greatest added value to regulatory bodies, by reducing costs and targeting the most culpable sources. The work described in this thesis was therefore to explore and develop suitable methods and techniques to help with cost-effective air quality monitoring. An approach which may add to the range of tools available is directional passive air sampling. A new flow-through directional passive air sampler (DPAS) was designed and tested to facilitate both enhanced sampling rates and pollution source locating and apportionment. Different from performing directional analysis on historical air monitoring data acquired by automatic monitors, the new sampler designs should be able to directly obtain direction-resolved air samples for source-concerning studies. Desirable features of such a device are discussed, and a possible design for sampling gaseous pollutants was conceived, and tested. Preliminary wind tunnel tests showed that it started to turn into the wind direction at fairly low wind velocity, and was successful in generating an identifiable directional result after short exposure in a pilot chemical test. Based on the first findings, the first prototype for gas directional sampling was re-designed and further characterised in the wind tunnel. Nitrogen dioxide (N02) was the test analyte. Uptake rates were derived, and linearity between the internal and external wind velocities established.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:619261 |
| Date | January 2011 |
| Creators | Lin, Chun |
| Publisher | Lancaster University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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