Wood Stoves a Major Contributor to “Unhealthy” Air Days in Clallam County, WA

Read The Biomass Monitor's coverage of the story behind these air pollution tests: "Tracking Biomass Air Pollution on the Olympic Peninsula" 

-  by Arwyn Rice, July 14, 2014, Peninsula Daily News  

[[{"type":"media","view_mode":"media_large","fid":"208","attributes":{"alt":"","class":"media-image","style":"width: 333px; height: 275px; margin: 3px 10px; float: left;"}}]]PORT ANGELES — Air quality in central and eastern Clallam County is generally good, but wood burning for home heating and transportation-related pollutants are contributing to occasional “unhealthy” air days, according to a year-long Olympic Region Clean Air Agency study.

Odelle Hadley, senior air monitoring specialist for the agency, presented the study to about 40 area residents during a meeting at the Port Angeles Library on Sunday.

The study, undertaken in 2013 to identify which location would best represent the area to test air quality, is a precursor to testing air quality impacts of the new co-generation biomass boiler at the Nippon Paper Industries USA Inc. plant in Port Angeles.

Nippon’s new biomass boiler — one of four boilers at the plant — was operational for about a month in November and December but has been under repair since, so the study does not reflect any impact the boiler may have on local air quality, Hadley said.

Prevailing winds during the brief operational period blew any pollutants from the Nippon site toward the Strait of Juan de Fuca and away from monitoring stations, she said.

The initial year of study provided a baseline air quality measurement and was used to determine where the most representative site for measurements is located.

The four optical particle counters used in the study assessed particles in the air of 2.5 microns and smaller but not as small as ultrafine particles, which are of particular concern to biomass-burn critics.

Three of the four have been moved to Jefferson County for a similar study.

An air monitor has been located at Stevens Middle School, 1139 West 14th St., and the study added three temporary sites: the Port Angeles Fire Department, 102 E. Fifth St.; the Port Angeles Library, 2210 S. Peabody St.; and in Sequim at the Clallam County Fire District No. 3 fire station, 323 N. Fifth Ave.

After comparing data, the site at Port Angeles Fire Department was most representative for the region, and the remaining particle counter will be moved to that site, Hadley said.

The process to move the site can take several months as it moves through the state Department of Ecology and the Environmental Protection Agency, she said.

“Good” air, by state standards, is described as containing no more than 13.4 micrograms of 2.5 micron particles per cubic meter of air, while 13.5 to 20.4 micrograms is considered “moderate.” Measurements above 20.5 indicate the air is “unhealthy for sensitive groups,” which Hadley said includes children, the elderly and those with health issues.

The study found summertime pollutants were relatively steady with little variation during the day.

In Sequim, data showed a relatively constant 7 to 8 micrograms from the start of the day to the end.

Port Angeles stations recorded lower levels — 4 micrograms per cubic meter at the Stevens site and 6 micrograms at the fire station and library.

Winter daily concentrations were considerably higher in Port Angeles, lower in Sequim and varied more during the day, Hadley said.

In Sequim, the winter air contained 5 to 6 micrograms during the larger portion of the day, with a 6 microgram spike at about 9 a.m. and rising to 9 micrograms at about 8 p.m.

Port Angeles stations recorded variety between the stations, with up to four micrograms difference between the fire station site and the Stevens site.

However, all four show a 9 a.m. peak rising to 10-12 micrograms and a spike that begins at 4 p.m. rising to 14-18 micrograms by 8 p.m.

The fire department site tended to reflect higher numbers, and the Stevens site showed lower numbers, Hadley said.

“Nearly all of the winter black carbon in late evening and early morning is from wood smoke,” she said.

Black carbon can be produced by burning biomass — such as firewood — or petroleum products.

Audience members suggested Stevens Middle School administrators be contacted to adjust physical education classes to avoid outdoor exercise during peak morning pollution hours.

During the summer, Sequim had consistently higher concentrations than Port Angeles.

“I was surprised a little bit,” Hadley said.

However, air quality was usually quite good, she said.

Hourly measurements showed Sequim had “good” air more than 90 percent of the summer, while Port Angeles good air measurements reached near 99 percent.

The Sequim results show a July 2013 spike to 14 micrograms that corresponded with the Lavender Festival and a mid-to-late September spike to 13 micrograms that corresponded with offshore winds that may have brought pollution from the Seattle area, she said.

She said that other spikes did not correspond to anything obvious, but Hadley speculated that it could be from construction or farming activity that stirs up dust, or from days when wind was calm, allowing the air to stagnate and concentrate pollutants.

In Port Angeles, winter pollutants were higher and exceeded 13.5 micrograms on four days, according to the study.

About 70 percent of hourly winter measurements were good, 22 percent were moderate and eight percent reached the unhealthy range or above.

In Sequim, about 92 percent of hourly measurements were in the “good” range, with about 7 percent in the moderate range and about one percent in the unhealthy range.