Yellowknife (July 16/04) - The smoke descending on the city this week, borne in on high winds from fires in the Yukon, may cause problems for people with lung or heart problems.

Dr. Andre Corriveau, chief medical health officer for the NWT, said that his staff is monitoring the situation, but a serious problem has yet to develop.

"People with respiratory illnesses would be the first affected by the smoke," he says, adding he has not heard of anyone falling ill from exposure to forest fire smoke -- this summer or in summers past.

Sharon Cook, director of patient care services at Stanton Territorial Hospital, says her hospital has not seen an influx of smoke exposure cases.

Asthmatics have been calling with questions, and are being referred to the Tele-Care hotline.

Smoke particulate has increased substantially in Yellowknife in recent days, but is not necessarily dangerous.

"It is still much lower than you'd have been exposed to in a bar until recently," says Corriveau.

Air quality in Yellowknife is monitored by the Department of Resources, Wildlife and Economic Development.

A particulate monitor is used to measure the proportion of fine particles in the air and produces a reading every hour. Twenty-four-hour averages are compiled to determine relative air quality.

Graham Veale, air quality programs co-ordinator, explains that the system collects particles around 2.5 microns in size, about one-fortieth the diameter of a human hair. The hourly readings are of micrograms per cubic metre of air.

"This equipment is top of the line," he says.

Readings in Yellowknife are generally in the five-10 micrograms per cubic metre range; Wednesday afternoon the hourly readings were approximately 160 micrograms.

Daily numbers are compared against a national ambient air quality standard of 30. The standard, says Veale, is health-based, but is still higher than Yellowknife's average.

"We have very clean air here, by and large," he says.

Corriveau says Yellowknifers not feeling any ill effects should not be alarmed by the smoke in the city.

"People have a high tolerance for smoke," he says.

The NWT Department of Health has released a factsheet on its Web site to educate people about the effects of forest fire smoke, including ways to avoid exposure.