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New study, new findings in air quality research |
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Written by GORDON HOEKSTRA
Citizen staff
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Friday, 04 April 2008 |
Pulp mill emissions, mobile sources and wood burning are the major contributors to the smallest fine particulates measured downtown, a study of monitoring data commissioned by the Prince George Air Quality Implementation Committee has found.
The study's findings differ from previous research, as it turns the focus away from road dust, and also puts the first parameters around mobile sources, which include diesel trucks and locomotives, as well as gasoline cars and trucks. It also points the finger at wood-burning appliances as a contributor to poor air quality downtown.
Mellissa Winfield-Lesk, chair of the Prince George Air Quality Implementation Committee, said the results weren't necessarily surprising to those engaged in the scientific process, but may be to the public.
"People see these huge smoke stacks and immediately pinpoint industry as a major source, and they are one of the major contributors, but it's difficult for them to conceptualize how many individual wood-burning appliances there are out there when you don't see them," she said.
But in terms of responsibility, nobody is getting off the hook, said Winfield-Lesk, who is an official with B.C. Environment in Prince George.
Everyone is eager to move forward, she said. "We're confident this is robust science that we can apply to our management regime."
Winfield-Lesk spoke to The Citizen Friday about the report, which has not been released officially, but was posted on the Prince George Air Quality Research Working Group's website.
The study -- carried out by California-based Sonoma Technology Inc., a leading North American expert in this kind of work -- is part of research the implementation committee is carrying out to pinpoint the sources contributing to fine particulate air pollution in Prince George.
Using data collected at the B.C. Ministry of Environment's downtown Plaza monitoring site, chemical signatures were used to analyze filter samples to determine the sources of the particulate.
The study examined fine particulates that are smaller than 2.5 microns, more commonly known as PM2.5, which are about 1/20 the width of a human hair. The PM2.5 is considered a significant health risk because the microscopic particles can penetrate deep into the lungs. Fine particulates are linked to respiratory and heart illnesses, as well as conditions like asthma.
Two different analysis methods were used, both using complex mathematical computations to derive results.
One determined that pulp mills contributed 24 per cent, burning 26 per cent, carbon (particularly from heavy duty diesel vehicles and light duty gas vehicles) 24 per cent, soil five per cent and an "other" category accounting for 20 per cent.
The other analysis determined that pulp mills were responsible for 24 per cent, burning 18 per cent, carbon 22 per cent, soil 10 per cent and an "other" category accounting for 26 per cent.
Still to come is a computer modeling study that uses an inventory of fine particulate sources, weather data and terrain information to see how pollutants would disperse in the airshed.
Winfield-Lesk said they may lean on those results more since there was significant local input into the emission inventory that drives the modelling study. (She said the preliminary results of that study are not too different from the Sonoma work).
Winfield-Lesk acknowleged that one of the uncertainties of the Sonoma study is that it only uses one local profile -- from Northwood pulp mill -- to determine the chemical signatures. The others come from outside the community, including a sawmill in Missoula, Mont., an asphalt plant profile from California, and road dust from Seattle. There was no chemical signature for an oil refinery.
The study also did an analysis of levoglucosan, which the report said is a proven molecular marker for wood smoke from residential fireplaces and forest fires.
A time series showed near zero concentrations of levoglucosan during the summer.
The 81-page report noted wood combustion is commonly used for power generation by industries in Prince George, including pulp mills and sawmills. "If levoglucosan was emitted from these sources, the concentration would be higher than observed in the summer because the industries operate all year," the report stated. "Residential wood-burning for home heating has a strong increase during winter, indicating that the dominant source of levoglucosan emissions is this type of wood burning."
Dave Fuller, president of the People's Action Committee for Healthy Air, is skeptical of the study results indicating that wood-burning appliances are a major contributor of PM2.5. Fuller has not read the final report, but is aware of the general conclusions. He said given his belief there is a low-level use of wood burning appliances for heat, particularly in the downtown area, the results just don't make sense.
The committee, which has more than 1,000 members, was formed out of a frustration that not enough was being done to improve air quality in Prince George.
Jo Graber, a long-time air quality advocate, said he thinks the conclusion wood-burning appliances are a major contributor to PM2.5 will be controversial. Graber, who recently joined the research working group, also said he has a belief that there's a low-level use of wood-burning appliances in the downtown area.
The Sonoma report noted that a recent Prince George survey showed that 15 to 20 per cent of home-heating needs in the area are met with wood-burning appliances.
Sonoma officials will be coming to Prince George this spring to hold a public information session.
The report will be posted on the air quality committees website -- www.pgairquality.com -- so people can view the report before the meeting.
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Last Updated ( Friday, 04 April 2008 )
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"Have you used wood as a heat source in your home in the past year?" Anyone who answered yes to that would automatically be branded as using wood as a heat source.
How convenient that they didnt measure the refinery or the plumes of dust from street sweeping we put up with every spring as a major source or particulate. Everyone knows these studies are a huge waste of time and taxpayers money.