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[Corrections] Seward ambient air quality tests completed

Bob Stark

Corrections (Mar. 9, 2012): Regretfully, the following story contained several significant errors in its original form, which Alaska Dispatch reposted from the Seward Journal here on Mar. 6, under the erroneous headline, "Coal dust no problem in Seward, despite local worries" and the erroneous page title, "Despite Alaskans' Worries, Tests Show Coal Dust Is No Problem in Seward."

The Department of Environmental Conservation sent Alaska Dispatch the following corrections through Barbara Trost, the air monitoring program manager for DEC's Division of Air Quality. They have been edited slightly for length, but are otherwise unchanged.

We apologize and regret republishing these errors.

  • The air monitors sample for a 24-hour period every 6th day, not every 24 hours as was originally written. The filter analysis performed determines the amount of particulate collected on a sample day, which can be used to calculate the concentration of particulate matter in the air that day. The result can be compared to the air quality standard set by EPA, which was adopted by the state.
  • Sampling started in 2011, not 2001.
  • In the report, DEC lists the major sources that may impact the sampling site, a common practice when installing sampling sites. However, contrary to what was written below, naming potential sources does not necessarily mean those are the sources of air pollution. To determine which sources actually impact a site would require a chemical analysis of the material collected on the air filter, which would need to be combined with analysis of wind patterns and other meteorological factors from that same day. But even with that analysis, it might not be possible to pinpoint every single source. To date, the DEC has not performed a chemical analysis on the sampled filters from Seward and as such did not make any statement regarding where the material is coming from. DEC would not typically do this more robust chemical analysis unless concentrations were close to or exceeding air quality standards.
  • The statement: "No coal dust was found" is premature. The monitoring survey only looked at how much material was in the air, not its composition.
  • A "national standard" and a "national average" are not the same thing. The national average would be an average amount of a pollutant found in the air of all communities across the country. A national standard is based on health information and is the amount of a pollutant EPA allows in a community's air.

After an array of complaints from locals about Seward's suspected coal dust problem, the city teamed up with the Alaska Department of Environmental Conservation, Alaska Native Tribal Health Consortium and the Qutekcak Native Tribe to develop an air-monitoring program to collect air samples from three different sites around town 24 hours a day.

Preliminary results indicate that Seward's air quality is far superior to the national average -- but first let's take a look at some of the technical terms involved in the study.

Air quality monitors record the particulate matter (PM10) in the air every 24 hours as well as the sources of those particulates, which come in many forms -- wood smoke, vehicle exhausts, cigarette smoke, candles, cooking, windblown silt, traffic dust, sanded roads, and coal dust, among other things. The number 10 refers to the size of the particulate matter in micrometers, with 10 micrometers being about a seventh the width of human hair.

The U.S. Environmental Protection Agency claims, "Concerns for human health from exposure to PM10 include: effects on breathing and respiratory systems, damage to lung tissue, cancer, and premature death. The elderly, children, and people with chronic lung disease, influenza, or asthma, are especially sensitive to the effects of particulate matter."

To protect air quality, the federal government has set the National Ambient Air Quality Standard (NAAQS) at 150 micrograms of PM10 per cubic meter every 24 hours. Anything below this standard is acceptable.

Testing in Seward began in 2001, with three monitor sites around town at varying distances from the Seward Coal Terminal. One is northwest on the roof at the Mountain Haven Facility; one is west of the terminal alongside Ballaine Boulevard and the last one is south of the terminal on the roof of Seward Community Library.

Seward's highest single concentration of 44 micrograms is only 29 percent of the national standard. In fact, the three Seward sites averaged only 9.6 micrograms per 24 hours.

The monitor on the roof of the Mountain Haven Facility is roughly two miles from the coal terminal. The device registered an average of 7 micrograms of PM10 per cubic meter per 24 hour time span. Sources of particulates were unpaved roads and traffic dust from the Seward High School, as well as wind-blown glacial silt from river beds on the north end of the Resurrection Bay. No coal dust was found.

The second monitor at Ballaine Boulevard is the closest to the coal terminal, only 0.8 miles west. Sources of particulate matter were wind-blown glacial silt from the soil, sand on icy roads, stockpiles of materials used for roadside maintenance, and coal dust -- with an average reading of 11. The highest level of PM10 registered at any site was here, with one reading of 44 micrograms. The site is surrounded by parking lots and plant-free areas, and perhaps more plant life would reduce the amount of particulate matter in the air.

The third site 1.4 miles southwest of the coal terminal sits on the roof of the Seward Community Library. The major sources particulates there came from glacial silt in the local soil (in open unvegetated areas), the deterioration of road surfaces, sand used in winter for icy roads, stockpiles of road maintenance materials, and coal dust from the terminal. The average level of PM10 per cubic meter per 24-hour time span was also 11.

The three monitors will continue to collect information every sixth day until May.

Some Seward residents plan to form a Bucket Brigade to monitor particulates themselves. The "bucket" is approved by the EPA and is strung along a person's fence to collect air samples and to give locals the ability to conduct their own tests. Bucket Brigades have been formed by residents across the country interested in taking their own samples and reporting their findings to officials.

So far, the measurements show that the amount of particulates that Seward residents breathe is sharply lower than the national average.

Bob Stark writes for the Seward Journal