Air pollution dispersion within the Tamar Valley
Power, M (2001) Air pollution dispersion within the Tamar Valley. PhD thesis, University of Tasmania.
The Tamar Valley is a well-defined coastal valley, located in northern Tasmania
(Australia). The valley has significant air pollution problems. At Bell Bay,
approximately 5 km inland, there is a heavy industrial estate containing an
aluminium smelter, a ferroalloy smelter, a medium density fibreboard plant and a
thermal power station. The city of Launceston (pop. 72 000) is located 65 km inland,
at the head of the valley. Launceston has a significant winter woodsmoke problem,
regularly exceeding the 24-hour National Environment Protection Council (NEPC)
goal for PM,o particles.
Data from a network of 16 meteorological stations were combined to produce a
climatology of the Tamar Valley, with many variables being mapped on a seasonal
basis. The most important climatological parameters were amalgamated into an
index of air pollution potential.
A diagnostic wind field model, NUATMOS was used to model hourly wind fields for
two-day periods each season under poor dispersion conditions. The modelled wind
fields clearly showed the dominant flows occurring in the valley under anticyclonic
conditions. Coastal westerlies and sea breezes are channelled inland along the
northwest-southeast aligned valley. At night, there is a transition to down-slope and
down-valley winds, which drain out of the valley.
The CITPUFF Gaussian puff dispersion model was used to simulate dispersion of
current winter woodsmoke emissions throughout the valley under poor-dispersion
conditions. This model was used to help devise woodsmoke reduction strategies.
The findings show that a 72 % reduction in woodheater numbers in Launceston is
required to meet the NEPC particle goal. This goal is exceeded only in the Launceston region, and is chiefly caused by local sources, with only 4% of the
particles modelled within Launceston originating outside of the city. Measured
particle concentrations in Launceston have declined over the past few years, however
additional measures are required if the NEPC goal is to be met. The introduction of
reticulated natural gas to Launceston will allow the NEPC goal to be met if the city
experiences an uptake to gas heating similar to that experienced by Canberra when
gas was introduced. A more realistic scenario, with an uptake half that of
Canberra's, would provide a significant reduction in PM,o concentrations, however
this alone would not meet the NEPC goal. Banning open fires and non-certified
woodheaters would come close meeting the goal. The goal is most likely to be met
using a combination of reduction measures.
Dispersion of SO2 from the combined Bell Bay industrial sources was modelled for
each season, showing frequent exceedences of the NEPC hourly goal for SO2. The
Bell Bay thermal power station was the dominant source, however this will shortly
be converted from oil-fired to gas-fired operation. Modelled NO^ emissions from the
gas-fired power station reveal a significant reduction in the number of exceedences.
|Item Type:||Thesis (PhD)|
|Additional Information:||Copyright © the Author|
|Keywords:||dispersion; modelling; smoke; industry; meteorology; Tamar Valley; Launceston|
|Deposited By:||UTAS ePrints officer|
|Deposited On:||18 Jul 2011 11:51|
|Last Modified:||17 Dec 2012 12:55|
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