References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-9-7997-2009

Now you see it, now you don't: Impact of temporary closures of a coal-fired power plant on air quality in the Columbia River Gorge National Scenic Area

Jaffe

D. A.

¹ Reidmiller

D. R.

¹ ²

Department of Science and Technology, University of Washington-Bothell, USA

Department of Atmospheric Sciences, University of Washington-Seattle, USA

23 10 2009

9 20 7997 8005

This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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The goal of this study is to identify major point sources that contribute to elevated particulate matter in the Columbia River Gorge, USA and to quantify their contribution. To answer this question we analyzed 14 years of aerosol data spanning 1993–2006 from the IMPROVE site at Wishram, Washington (45.66° N, 121.00° W; 178 m a.s.l.) in the Columbia River Gorge (CRG) National Scenic Area of the Pacific Northwest of the USA. Two types of analyses were conducted. First, we examined the transport for days with the highest fine mass (PM2.5) concentrations using HYSPLIT backtrajectories. We found that the highest PM2.5 concentrations occurred during autumn and were associated with easterly flow, down the CRG. Such flow transports emissions from a large coal power plant in Boardman, Oregon and a large agricultural facility into the CRG. This transport was found on 20 out of the 50 worst PM2.5 days and resulted in an average daily concentration of 20.1 μg/m3, compared with an average of 18.8 μg/m3 for the 50 highest days and 5.9 μg/m3 for all days. These airmasses contain not only high PM2.5 concentrations, but also elevated levels of aerosol NO3−. In the second analysis, we examined PM2.5 concentrations in the CRG during periods when the Boardman power plant was shut down due to repairs and compared these values with concentrations when the facility was operating at near full capacity. We also examined this relationship on the days when backtrajectories suggested the greatest influence from the power plant on air quality in the CRG. From this analysis, we found significantly higher PM2.5 concentrations when the power plant was operating at or near full capacity. We use these data to calculate that the contribution to PM2.5 mass in the CRG from the Boardman power plant was 0.90 μg/m3 averaged over the entire year, 3.94 μg/m3 if only the month of November is considered and 7.40 μg/m3 if only November days when the airflow is "down-gorge" (from east to west). This represents 14, 46 and 56% of the PM2.5 mass in the CRG for the full year, November only and November days with "down-gorge" transport, respectively.

References 1

Draxler, R. and Rolph, G. D.: HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) Model access via NOAA ARL READY web site, NOAA Air Resources Laboratory, Silver Spring, MD, 2002, available at: http://www.arl.noaa.gov/ready/hysplit4.html, last access: May 2009.

Eatough, D. J., Richter, B. E., Eatough, N. L., and Hansen, L. D.: Sulfur chemistry in smelter and power-plant plumes in the western United States, Atmos. Environ., 15(10-1), 2241–2253, 1981.

Eldred, R. A., Ashbaugh, L. L., Cahill, T. A., Flocchini, R. G., and Pitchford, M. L.: Sulfate levels in the southwest during the~1980 copper smelter strike, J. Air Pollut. Cont. Assoc., 33(2), 110–113, 1983.

Fenn, M. E., Geiser, L., Bachman, R., Blubaugh, T. J., and Bytnerowicz, A.: Atmospheric deposition inputs and effects on lichen chemistry and indicator species in the Columbia River Gorge, USA, Environ. Pollut., 146(1), 77–91, 2007.

Green, M., Xu, J., Adhikari, N., and Nikolich, G: Causes of Haze in the Gorge (CoHaGo), Final Report. Southwest Clean Air Agency, available at: http://www.swcleanair.org/gorgereports.html, released July 2006.

Hewitt, C. N.: The atmospheric chemistry of sulphur and nitrogen in power station plumes, Atmos. Environ., 35(7), 1155–1170, 2001.

Malm, W. C., Schichtel, B. A., Ames, R. B., and Gebhart, K. A.: A 10-year spatial and temporal trend of sulfate across the United States, J. Geophys. Res., 107(D22), 4627, doi:10.1029/2002JD002107, 2002.

Malm, W. C., Sisler, J. F., Huffman, D., Eldred, R. A., and Cahill, T. A.: Spatial and seasonal trends in particle concentration and optical extinction in the United States, J. Geophys. Res., 99(D1), 1347–1370, 1994.

Pitchford, M. L, Green, M. C., Morris, R., Emery, C., Sakata, R., Swab, C., and Mairose, P. T.: Columbia River Gorge Air Quality Study, Final Science Summary Report, available at: http://www.swcleanair.org/gorgereports.html, released Feb 2008.

Romo-Kröger, C. M., Kiley, J. R., Dinator, M. I., and Llona, F.: Heavy metals in the atmosphere coming from a copper smelter in Chile, Atmos. Environ., 28, 705–711, 1994.

Seinfeld, J. H. and S. N. Pandis: Atmospheric Chemistry and Physics: From Air Pollution to Climate Change, 2nd Edn., Wiley-Interscience, Hoboken, New Jersey, 1232 pp., 2006.

Sharp, J. and Mass, C. F.: Columbia Gorge Gap Winds: Their Climatological Influence and Synoptic Evolution, Weather Forecast., 19(6), 970–992, 2004.

Vong, R. J., Moseholm, L., Covert, D. S., Sampson, P. D., O'Loughlin, J. F., Stevenson, M. N., Charlson, R. J., Zoller, W. H., and Larson, T. V.: Changes in rainwater acidity associated with closure of a copper smelter, J. Geophys. Res., 93(D6), 7169–7179, 1988.