State air quality officials, Logan residents, seek ways to curb PM 2.5 pollution

By J.P. Rodriguez

February 6, 2009 | LOGAN -- Officials from the State Division of Air Quality met with concerned Cache Valley residents Feb. 3 in a public meeting to discuss the state implementation plan (SIP) that will help Cache Valley attain the EPA standards for the air pollutant known as PM 2.5.

PM 2.5 stands for particle matter suspended in the air that is less than 2.5 microns in size. According to Bill Reiss, implementation plan coordinator for the Division of Air Quality, these are particles that can cause health problems.

The point of reducing these particles is to "protect the most sensitive in the population, health wise," explained Reiss. These include young and older people, as well as those who may have pulmonary problems.

These particles are small enough to get into the lungs and blood, and are difficult for the body to expunge from its systems, he said, adding he was reluctant to answer medical specifics, because he is not a physician.

The EPA keeps track of PM 2.5 levels for two specific time periods. One is a yearly average while the other is a 24-hour period. While Logan does not have a problem with the yearly average, Reiss said it often fails to meet requirements for the 24-hour periods.

Revisions made in December 2006 to the EPA's air quality regulations require that, for a one-day period, there be fewer than 35 particles sized 2.5 microns or less per cubic meter of air. At levels higher than this, health issues appear in the population, Reiss said.

Periods when the levels exceed this limit are the so-called "red days."

"Weather and topography is a major issue here," explains Reiss. Because Cache Valley is surrounded by mountains, pollution has no place to go or dissipate because of winds. To add to this complication, during the winter inversion periods small particles in the air accumulate, which are the periods when we have problems.

These particles "start as gas, and combine with compounds to become a particle," Reiss said. Gases such as sulfur dioxide and nitrogen oxide combine with other elements, and eventually become ammonium sulfate or ammonium nitrate.

Under EPA regulations, it is required that a SIP be prepared in order to implement regulations and standards to bring down PM 2.5 levels in the Cache Valley area, which includes the northern end of Cache county and the southern part of Franklin county in Idaho.

As part of the process, the Division of Air Quality will take several steps to draft and implement the SIP. Among them, they will use a complex mathematical model that can aid them to measure the pollution in the area, and will tell them how different regulations may affect particle level in the valley. In order to have accurate models, large amounts of date have been and are still being collected in the valley.

"We have to make these improvements on the face of a growing population," said Reiss, explaining that as part of the model, the expected growth in the valley has to be taken into account, adding to the complications of these models.

The SIP will also set forth regulations and administrative measurements that will have to be implemented locally to reduce the levels of PM 2.5. Reiss said that while the model will "Shoot for the best," the main goal of the SIP is only intended to keep levels of particles "Under the line" of 35 microns per cubic meter.

Reiss explained that there are three types of sources that cause this kind of pollution in the air: point, area, and mobile sources. Point sources are places like large smoke stacks, while area sources are smaller sources in an area. Mobile sources are the many vehicles in the valley.

"Vehicle inspections may make the most significant impact. A few vehicles pollute the most," he said, explaining that inspections are a way to both bring these vehicles back to standard, as well as a way to provide funding for the program. He adds that while federal regulations required local areas to med these standards, no funding aid is provided to accomplish this standards.

"It is not going to solve the problem," said Reiss about the SIP, reiterating however that the intention of the SIP process is only to reduce levels of PM 2.5 in the area, and bring Cache Valley "under attainment levels."

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