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Air pollution findings need fine tuning, expert says |
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Written by GORDON HOEKSTRA
Citizen staff
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Friday, 14 November 2008 |
The contribution of diesel locomotives is too high in the latest research to pinpoint sources of the smallest fine particulate air pollution in the Prince George airshed and will be fixed, UNBC air pollution expert Peter Jackson said Friday.
The new significant source is identified in the preliminary finding of a long-awaited study. The research work, which is being overseen by UNBC, is being carried out to provide a scientific basis for improving air quality in Prince George which perennially ranks among the communities in B.C. with the worst levels of fine particulates. The microscopic dry and liquid particles are increasingly considered a health hazard because the can penetrate deep into the lungs and even be absorbed into the blood stream.
Jackson stressed the research findings remain preliminary until a third-party review is complete -- and following further examination by a research working group that answers to the Prince George Air Improvement Roundtable -- but added that the diesel locomotive contributions will likely be halved.
That's because a complex computer-modelling exercise used peak emissions of the locomotives rather than average emissions, Jackson told an audience of about 70 at UNBC.
The modelling -- which Jackson outlined in a presentation largely to students and university instructors -- predicted that locomotives were responsible for 31 per cent of the fine particulate air pollution downtown, while industrial sources like pulp mills and sawmills were responsible for 30 per cent.
The preliminary results also indicated that commercial sources were responsible for 10 per cent of the smallest fine particulates downtown, and that residential sources and secondary formation of particles accounted for seven per cent each.
While the broad categories of sources and their levels matched earlier research -- where pulp mills have been identified -- the locomotive emissions were a new source. The vast majority of the locomotive emissions are attributed to the only railway company operating in Prince George, CN.
"Right now we're fine-tuning that emission inventory and getting feedback from CN on it," Jackson told reporters following his presentation.
Once the emission inventory is adjusted the computer model will be run again.
The U.S. Environmental Protection Agency -endorsed model that is being used is called CALPUFF, It uses weather and terrain data, coupled with the emission inventory, to calculate the level of fine particulate air pollution in a particular area, in this case a 40-kilometre square area that encompasses the Prince George airshed.
Jackson said other emission sources that could be adjusted include mobile sources on roads, which includes diesel trucks and gasoline cars.
He also noted that the third-part review, which is expected to be complete before the end of the year, could also find areas in the model that need to be changed.
Jackson said the research has also introduced population as a health-factor measure. The air pollution levels are weighted to the population in a given area. It indicates a lower impact in populated areas than in downtown or in an industrial area like the BCR industrial site. However, Jackson said the population weighting does not take into account the fact people work downtown and in the BCR industrial site.
All the latest research is expected to be weighted against previous research to produce a report that will form the basis for the next stage of an air pollution reduction plan sometime in 2009.
The air pollution reduction reduction effort is being led by the recently-renamed Prince George Air Improvement Roundtable. The roundtable includes representatives from the province, city, industry, Northern Health and the public, many of which contributed to the $210,000 CALPUFF computer modelling study.
The modelling study has been three years in the making and is already a year behind schedule.
A Citizen investigation, published last fall, found that little urgency had been applied to improving air quality in Prince George in the past decade.
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Last Updated ( Friday, 14 November 2008 )
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