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South Park
Air Monitoring
South Seattle residents started noticing an unpleasant smell in the air in Spring 2001. Many described the odor as “chlorine-like,” “acrid” and “caustic,” and some said it affected their breathing.
The complaint locations varied from the South Park and Georgetown neighborhoods to West Seattle, Beacon Hill and Highland Park. But with so much industry in the vicinity, it was difficult to determine where the bad smell was coming from or if the odor was coming from just one source or a combination.
Puget Sound Clean Air Agency records show over 200 businesses registered as active sources of air pollution in the Duwamish Valley, an area of mixed industrial and residential land use. Agency staff investigated by looking at various industries and utilities that use or store chlorine or chlorine-like compounds or emit nitrogen oxide (NOx) and sulfur dioxide (SO2).
This search was inconclusive, but circumstantial evidence pointed to the Lafarge Cement plant, located a few miles north of where the odor complaints were generated.
We welcome your suggestions. Please contact Mike Gilroy.
Data monitoring captures elevated levels
However, the agency wanted better information to substantiate the source of the odors.
Prior to 2004, the closest, active NOx monitoring station was located atop Beacon Hill. Another monitor located in Georgetown until 2002 had indicated NOx emissions were primarily associated with heavy traffic on Interstate 5 as opposed to industrial sources in the Duwamish Valley. However, data from these two air monitoring stations weren’t necessarily representative of the areas due to differences in prevailing winds, climatology, elevation and local geography.
In order to pinpoint the primary cause of these odors, the agency harnessed new technology to monitor target pollutants such as the suspected NOx and SO2. The agency purchased and installed a new technology called “open path” monitors at South Park and Highland Park. These monitors, continually gathering data at five-minute averages, can detect NOx and SO2 at much lower concentrations than odor thresholds and are similar to federal reference monitors.
From summer into fall 2004, real-time pollutant measurements and near-by wind direction were documented and compared with odor complaints reported to the agency by South Seattle residents. If was often found that when the wind blows from the north and there were elevated concentrations of NO and SO2, odor complaints were reported to the agency by South Seattle residents.
The agency gathered and compared data from the South Park and Highland Park monitors again in summer 2005. Preliminary data was summarized and posted online weekly, showing NO and SO2 concentrations, wind direction and any odor complaints reported from the area. Data gathering began May 9 and continued into September, 2005.
Improvements underway
While not agreeing with the agency’s finding, Lafarge, never the less, agreed to look for ways to reduce its emissions and potential impact on the environment as a result of the cement-making process.
The company has since installed a new computer system with sensors throughout the plant. The system integrates all production steps to prevent or stop kiln upsets. Although not yet fully automated, since its installation, the plant’s NOx emissions are down.
The Seattle plant also added Lafarge’s NewCem® product to its lineup in 2005. Because the product requires fewer raw materials, Lafarge will be firing its kiln less so emissions are dramatically reduced during the high-heating process.
Report odors
Residents are encouraged to report odor concerns by calling 206-343-8800 or 800-552-3565. Please note, as specifically as possible, the time the odor was noticed, the address where the odor was detected and any other specific details about the problem, along with your name and daytime phone number.
