This just in from the Alaska Dispatch:
Readings at a North Pole, Alaska, air quality monitor on Tuesday showed hazardous levels of particulate pollution. Those levels, according to Dermot Cole of the Fairbanks News-Miner, are up this week, leading to an “unhealthy” air quality forecast from the Fairbanks North Star Borough.
On Tuesday, temperatures in North Pole ranged from minus-19 F to minus-28 with little wind. Increasing winds on Wednesday were expected to drive the wind chill down to minus-55.
“Air quality in the borough is classified as very unhealthy and exceeds the EPA health limit for fine particulate pollution,” according to an alert from the National Weather Service. “People with respiratory or heart disease, the elderly, and children should avoid any outdoor activity. Everyone else should avoid prolonged exertion. The air quality is forecast to remain very unhealthy in North Pole.”
A North Pole air-quality monitor showed a reading of 267 micrograms per cubic meter at noon Tuesday. For a 24-hour stretch, readings exceeding 250 are considered hazardous.
Particle pollution consists of a mix of solid particles and liquid droplets in the air. Some particles, such as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked eye. Others can only be detected using an electron microscope.
The EPA terms “inhalable course particles” as those between 2.5 and 10 micrometers. By comparison, human hair is about 70 micrometers in diameter.
According to the EPA, “good air” contains fewer than 12 micrograms per cubic meter of particulate pollution averaged over a 24-hour period. But in North Pole and Fairbanks, an inversion — cold stagnant air trapped on the valley floor by warmer air above — magnifies pollution released from wood stoves, cars and oil furnaces.
In contrast to North Pole’s high readings, the highest reading in California on Monday was 47 micrograms per cubic meter, according to the News-Miner. The highest in Shanghai was 54.