The B.C. Ministry of Environment is continuing efforts in Prince George to try to pinpoint the source of odours that Millar Addition residents say are an irritant and a health concern.
The environment ministry recently wrapped up a formaldehyde sampling program that found no evidence of high levels, and has now turned its attention to other volatile organic compounds (VOCs) which can give off odours, said environment ministry regional manager Dean Cherkas. "We are further researching compounds that could be responsible for the odour complaints received," said Cherkas in an e-mail response.
No conclusions have been drawn from the initial samples, said Cherkas.
The first three VOC samples taken on March, 9, 10 and 15 near Fort George Park did not exceed the objectives they were measured against, largely thresholds from Texas, and a lesser number of standards from Ontario and Alberta.
Of the 190 VOCs the environment ministry tested for, only a handful were highlighted because the concentrations of the others were less than five per cent of the objective levels.
Acrolein, which may be formed from the breakdown of pollutants, was measured at 1.69 micrograms per cubic metre to 2.92 micrograms per cubic metre, ranging from 38 per cent to 65 per cent of an Ontario objective level.
Acrolein has a burned, sweet, pungent odour that most people may begin to smell at concentrations of 600 micrograms per cubic metre, according to the environment ministry.
Other VOCs that were detected at the highest concentration measured against objective levels included a-Pinene, methyl vinyl ketone and b-Pinene.
All of these VOCs were detected at low levels in the sampling.
The pinenes are emitted by a wide variety of vegetation, including softwood trees, but can also be emitted from pulp mills. Methyl vinyl ketone is an emission from trees, but can also be emitted from various waste streams, according to the environment ministry.
