Brent Reaney
Northern News Services

Yellowknife (Aug 24/05) - Smoke blown in from Alaskan forest fires cast a haze over Yellowknife, beginning Monday morning.

"Alaska has some pretty large fires on the east side," said Roger Fraser of the department of Environment and Natural Resources.

A website maintained by the United States Forest Service showed seven Alaskan fires as active Tuesday morning.

According to Environment Canada, the smoke has been tracked up to 12,000 feet in the atmosphere. As it rises, the smoke particles are carried by strong air currents.

"It's like a river of air and if you happen to be at the end of that, then you're going to get the smoke," said Yvonne Bilan-Wallace with Environment Canada.

The smoke is expected to last until the end of the week, but a change in the wind pattern could clear the air within hours.

Last summer, smoke from fires burning in the Yukon brought a similar problem.

People with respiratory problems are encouraged to remain indoors - with the windows closed - because of the small particles in the smoke.

Measuring about 2.5 millionths of a metre thick, even a pollution mask is will not catch the particles.

By comparison, a human hair measures about 80 millionths of a metre.

"It can bypass your nose and throat defences and it gets right down deep into your lungs," said Graham Veale, who monitors air quality with the GNWT.