By SHANNON HAUGLAND
Sentinel Staff Writer
The Alaska Division of Air Quality says smoke from northern wildfires is not expected to have more than a “moderate” effect on Sitka’s air quality this weekend.
“It’ll be moderate, if any impacts at all,” said Mark Smith, meteorologist for the Department of Environmental Conservation’s Division of Air Quality.
Smith sent out an advisory about air quality today, regarding “degraded air quality” in Southeast, the result of Canadian wildfires.
Areas as far south as Sitka, and on the ocean, should not be as affected as communities farther north and inland, such as Haines and Juneau, Smith said.
“The worst case I believe will be ‘moderate,’” he said of Sitka.
Smith, who is based in Anchorage, said in his advisory that the air flow around the east side of the high pressure system in Southcentral Alaska is taking smoke from Canadian fires into the Panhandle.
“This pattern is expected to persist through the first part of next week,” he said. “Air quality will vary between ‘good’ and ‘very unhealthy’ depending on fire intensity and the amount of smoke lifted into the transport winds.”
Sitka’s air quality will be helped by “afternoon sea breezes keeping smoke out of the lower elevations,” Smith told the Sentinel. “Being farther south gives the smoke time to dissipate or mix out.”
Smith included a chart of cautionary statements for each range of air quality, and possible steps to take. Air quality is rated on the effect of smoke on miles of visibility.
The “good” air quality category (10 and more miles of visibility) has no “cautionary statements.”
The “moderate” air quality category (6 to 9 miles) says “Unusually sensitive people should consider reducing prolonged or heavy exertion.”
Other categories are “unhealthy for sensitive groups (3 to 5 miles),” “unhealthy (1.2 to 2.5 miles),” “very unhealthy (.9 to 1.4 miles)” and “hazardous (.8 miles or less).”
The DEC advisory, which is in effect through Monday, says: “Be aware that areas immediately downwind of any fire will experience ‘hazardous’ levels of smoke. Generally, worse conditions occur overnight and during the early morning hours, as the atmosphere cools and brings smoke to the surface. During the day, surface heating will mix smoke and carry it upwards, temporarily improving air quality.”
