Fairbanks inversion

An inversion traps cold air and pollution across the city during a cold day in Fairbanks in January 2012.

New modeling shows that smoke pollution levels in the Fairbanks area are on track to be cut in half by 2024.

The modeling supposes that residents avoid burning wood on bad air days and that thousands of homes and businesses switch from No. 2 grade heating oil to cleaner but more expensive No. 1 grade oil in the next two years.

State Air Quality Program Manager Cindy Heil said she is hopeful the new modeling means the Fairbanks North Star Borough is on track to satisfy requirements in the federal Clean Air Act.

“This assumes that all of the control measures in the Serious SIP (state implementation plan) continue and people comply,” Heil said. “We cannot relax.”

The state announced the new modeling Friday along with a new public comment period on a change to the Serious SIP, which is the name for the state plan for reducing pollution.

Smoke levels rise on cold winter days when the air is stagnant and exhaust from chimneys and tailpipes lingers at ground level. The main concern is a toxic, almost-invisible, substance in the smoke known as PM2.5.

An area of the borough covering the two cities and neighborhoods in between is under federally required monitoring and tight rules for what can come out of chimneys on days that PM2.5 levels are high.

The pollutant has been shown in study after study to degrade human health.

The only change proposed for the state’s pollution-control plan would add a new contingency measure “if PM2.5 levels are not headed in the right direction,” according to a news release Friday from the Alaska Department of Environmental Conservation.

The new proposed contingency measure lowers the threshold for burn bans from 30 micrograms of PM2.5 per cubic meter to 25 micrograms per cubic meter.

“The measure would be triggered if the area fails to show continued progress in lowering PM2.5 levels to achieve federal air quality standards or fails to meet any requirements by the target dates in the updated Serious SIP. DEC does not anticipate that the new contingency measure would be triggered before 2024,” the news release states.

A telephonic public hearing is scheduled for Oct. 15 at 6 p.m. The public comment period for the modified SIP ends Oct. 29.

According to Heil, the new modeling showing attainment in four years uses data from recent years, 2016-2019, in which the air quality has improved, as a baseline.

Previous modeling used preceding years, when the air was worse, as a baseline, Heil said.

“We can show attainment because we now get to use the latest modeling data,” she said.

The modeling was performed by a contractor hired by the state, and the U.S. Environmental Protection Agency will be checking the math, she said.

Several air pollution control measures are ready now to go into effect in the coming years. Those measures are factored into the new modeling.

One new measure starts in a few weeks. As of Oct. 2, all stoves 25 years old or older with a particulate matter emission rating of more than 2 grams per hour are required to be removed before the sale or lease of a building.

In the fall of 2021, a requirement for wood sellers to sell only dry wood takes effect.

In 2023, power plants will come under new stricter rules.

By the end of 2024, small-scale coal-fired heaters and outdoor hydronic heaters must be removed in the federally recognized area known as the air quality nonattainment area.

Contact staff writer Amanda Bohman at 459-7545. Follow her on Twitter: @FDNMborough.