Investigations on Fairbanks air quality: Team examines meteorological conditions for elevated PM2.5

July 11, 2011

 

Despite a minimal population and vast terrain, air quality is a challenge in some Alaska communities. During the winter months, the Interior city of Fairbanks traditionally exceeds the 24 hour National Ambient Air Quality Standard, or the NAAQS. Professor Nicole Mölders of the Geophysical Institute’s Atmospheric Sciences group and doctoral candidate Huy Tran are investigating what causes elevated particulate levels in the community. 

 

“When you have an air quality problem, the first thing you have to do is an inventory to see what is causing the problem,” Mölders said. “You look at the meteorological situation and the emissions and the situation when you have the exceedences [of the NAAQS].”

 

From the winters of 2004 to 2009, there were 128 exceedances of the NAAQS. Mölders and Tran examined observational data collected in Fairbanks’ city center from the winters of 1999 to 2009. What they found is that concentrations of PM2.5 — fine particulate matter smaller than 2.5 microns in diameter — occurred during winter under calm wind, extremely low temperature, low humidity and multi-day surface inversions. The meteorological recipe for exceedances is that the inversion traps the pollutants near the ground, in the breathing level, and the calm wind (<2.2 mph) inhibits transport of the noxious aerosols out of the area. 

 

Surrounding topography compounds the air quality problem. Fairbanks is bordered by hills on three sides, which restrains the exchange of air in the horizontal direction, while the inversion inhibits the exchange in the vertical direction. Mölders compares it to being situated in a Crock-Pot with a tight lid, but without the heat.

 

Plummeting temperatures also play an important role in the air quality problem. From November through February, an abundance of PM2.5 exists due to traffic and other combustion processes used for heating and power generation. Since its unlikely that topographic and winter meteorological conditions will soon change, this leaves a greater responsibility on Fairbanksans themselves to improve the air quality of their city by making slight adjustments to how they respond to those low temperatures. 

 

Since traffic is the cause for roughly 30 percent of the PM2.5 problem in downtown Fairbanks, cold starts and the idling of vehicles could be reduced. In addition, smarter choices for home heating would benefit local air quality. 

 

“People have to burn wood efficiently to reduce the problem,” Mölders said. “It’s important that people are educated on how they burn wood and that they burn seasoned wood.” 

 

According to the Fairbanks North Star Borough, wood smoke is the source of more than 60 percent of the PM2.5 particles found at monitoring sites in the Fairbanks area. Therefore, burning dry, seasoned wood could make a difference by curtailing the amount of harmful emissions. 

 

Exploration of the Fairbanks air quality issue allows Huy Tran the opportunity to do applied research and his studies will ultimately improve the very city in which he lives. This opportunity may be fairly common among graduate students at the GI, but it’s unique when compared to most graduate programs in the country.

 

“I’m always interested in doing research that contributes to the community,” Huy said. “This research gave me a great opportunity [that will help] when I apply for jobs after graduation.”

 

The graduate student continues to research Fairbanks air quality and is currently examining the impacts of traffic and wood stoves on the issue. Tran graduates in 2012.