Boise implemented new air pollution controls over decades — and it now shows. Here’s how

Earlier this month, the Trump administration decided against setting tougher standards for soot emissions from cars and industrial plants.

Scientists from the Environmental Protection Agency had recommended lowering the standard by up to one fourth the current level. Reducing the limit could save between 9,000 and 34,600 lives annually, the scientists said in a draft report.

The outgoing administration officials weren’t the only ones reducing air pollution rules. In 2017, the Idaho Legislature passed a law that allowed farmers to burn fields even though they increased ozone pollution levels.

Dr. Karen Miller, a pulmonologist at St. Luke’s Medical Center, said people with lung diseases like asthma are sensitive to even moderate levels of air pollution.

“I’m seeing a lot of my patients are more aware about the air quality around us in just the last couple of years,” Miller said. “They are using the (EPA) AirNow app on their smartphones to make their decisions about whether to go outside.

“They know they can’t depend on the federal government or the state government to manage their lung disease,” Miller said.

Threat of air violation drops

The temperature inversion that trapped cold air and soot near the ground in the Treasure Valley under a layer of warmer air during the first 10 days of December was relatively mild at raising the area’s level of soot, which is made up of tiny particles that can be breathed deep into the lungs and ultimately the bloodstream. But it did not threaten to exceed federal standards.

For the near future, the Treasure Valley doesn’t appear to be facing an imminent threat of violating the Clear Air Act in the Treasure Valley, despite continued rapid growth.

“For the short term, the biggest concern is a nasty inversion in the wintertime,” said David Luft, air quality specialist for the Idaho Department of Environmental Quality.

Reduced traffic this year due to the COVID-19 pandemic is one of the reasons. Auto volume on Interstate 84 dropped more than 26% from June 2019 to 2020, according to the Community Planning Association of Southwest Idaho.

Pollution control in the Treasure Valley has worked

But a series of actions over the past 40 years in the Treasure Valley, from testing automobiles, to cleaner cars to planning and zoning that reduced automobile trips to burning restrictions and dust control have made our air cleaner, especially in the winter. These actions, done under federal orders, state law and voluntary action, have allowed the region to grow largely unimpeded by onerous federal restrictions.

In 2013, a shroud of warmer air settled above Ada and Canyon counties, trapping stagnant cold air against the Foothills for 11 days that January. The worst inversion since 1985 also built up soot, known formally as pm 2.5, which stands for particles 2.5 microns or smaller. Pollution levels were high enough that they threatened healthy people.

“This latest inversion was not bad at all. Not like ones that I have seen in prior years,” said Dr. Perry Brown, a pediatrician and co-director of the Cystic Fibrosis Center of Idaho.

Brown said the Treasure Valley has one of the highest rates of lung cancer among nonsmokers in the nation, and he believes pollution is one of the reasons.

Planners predict lower emissions

Planners have sought to limit the growth of vehicle miles traveled in the Treasure Valley as a way to control the man-made pollutants. The planning association, or COMPASS, uses computer models to forecast future vehicle emissions and compares those to established pollution ‘budgets’ for specific pollutants designed to keep them within limits.

“Despite the anticipated growth in population and vehicles miles traveled, we forecast that emissions will stay below those budgets through at least 2040,” said Matt Stoll, COMPASS executive director.

Efforts to reduce greenhouse gases that cause climate change will reduce this wintertime soot pollution even more.

“Overall, the vehicles driving our roads are getting ‘cleaner,’ with continual increases in the number of electric, hybrid, and fuel-efficient models,” he said. “This helps offset the growth in vehicle miles traveled.”

But the climate change has already lengthened the fire season and with hotter and drier summers smoke, a form of particle pollution, has filled the valley for weeks on end. Managing the smoke, which often comes from fires far away, has proven difficult.

But Scott Ki of the Idaho Conservation League said the change in the administrations should address the cause of the fires and help clean up man-made emissions.

“President-elect Biden has stated his support for increasing fuel efficiency and helping consumers shift to electric vehicles,” Ki said. “This shift will both improve Treasure Valley air quality and help fight climate change. “

Forty years of air pollution in the Treasure Valley

OZONE

A form of oxygen that causes burning of the lungs even at low levels. It irritates the eyes and other tissues and aggravates existing respiratory and cardiac conditions. Prolonged exposure can cause permanent damage to the lungs.

Ozone forms when nitrogen oxide, emitted primarily from cars, mixes with volatile organic chemicals in the atmosphere and is “cooked” by sunlight. The chemicals come from a wide variety of sources including cars, which also are major sources of nitrogen oxide. Another source of volatile organic chemicals is fumes of gasoline emitted from gas stations and tank farms.

PARTICULATES

Federal standards for larger particles - 10 microns or less - were relaxed in 1997, and the Valley meets federal standards. Standards for smaller particles — 2.5 microns or less (a human hair is about 70 microns in diameter) — were strengthened in 2012. The Valley exceeded the standards during the 2013 inversion but did not exceed the three-year standards because of exemptions for wildfire smoke.

The pollution comes directly from sources such as automobiles, industrial plants and burning wood. It also forms when gases from burning fuels react with water vapor and cold, stagnant air. Those smaller particles, also known as soot, are breathed most deeply into the lungs and are considered the most hazardous to human health.

The EPA says particulate pollution has been linked to heart attacks and other medical problems. An EPA study in the 1980s conducted in Boise showed that auto pollution increased the risk of lung cancer and could cause 88 people in Ada County to be stricken.

CARBON MONOXIDE

An odorless, colorless gas produced by burning fossil fuels. It interferes with the ability of blood to carry oxygen to organs and tissue, slowing reflexes, causing confusion and reducing the ability to learn. From 1978 to 2003, Boise was designated a “nonattainment area.” Boise exceeded the eight-hour standard 55 times in 1979. The last time Boise exceeded federal standards was in 1987. Federal tailpipe emission limits required all cars to reduce carbon monoxide in the mid-1970s. As the older cars disappeared, the carbon monoxide problem in the Treasure Valley dissipated.

This story was originally published December 15, 2020 at 4:00 AM.