ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-8-6297-2008 Trans-Pacific dust events observed at Whistler, British Columbia during INTEX-B McKendry I. G. 1 Macdonald A. M. 2 Leaitch W. R. 2 van Donkelaar A. 3 Zhang Q. 4 Duck T. 3 Martin R. V. 3 Department of Geography, The University of British Columbia, Vancouver, B.C., V6T 1Z2, Canada Science and Technology Branch, Environment Canada, Toronto, Ontario, M3H 5T4, Canada Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS M3J 1P3, Canada State University of New York at Albany, Albany, New York, USA 30 10 2008 8 20 6297 6307 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. This article is available from http://www.atmos-chem-phys.net/8/6297/2008/acp-8-6297-2008.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/8/6297/2008/acp-8-6297-2008.pdf

The meteorology and physico-chemical characteristics of aerosol associated with two new cases of long range dust transport affecting western Canada during spring 2006 are described. Each event showed enhancements of both sulfate aerosol and crustal material of Asian origin. However, the events were of quite different character and demonstrate the highly variable nature of such events. The April event was a significant dust event with considerable enhancement of fine particle sulfate while the May event was a weaker dust event, also with significant fine particle sulfate enhancement. The latter event was notable in the sense that it was of short duration and was quickly followed by a large increase of organic material likely of regional origin. Comparison of these two events with other documented cases extending back to 1993, suggests that all dust events show coincident enhancements of sulfate and crustal aerosol. However, events vary across a wide continuum based on the magnitude of aerosol enhancements and their sulfate to calcium ratios. At one extreme, events are dominated by highly significant crustal enhancements (e.g. the well-documented 1998 and 2001 "dust" events) while at the other are events with some dust transport, but where sulfate enhancements are of very high magnitude (e.g. the 1993 event at Crater Lake and the 15 May 2006 event at Whistler). Other events represent a "mix". It is likely that this variability is a function of the comparative strengths of the dust and anthropogenic SO<sub>2</sub> sources, the transport pathway and in particular the extent to which dust is transported across industrial SO<sub>2</sub> sources, and finally, meteorological and chemical processes.

 References Brock, C. A., Hudson, P. K., Lovejoy, E. R., Sullivan, A., Nowak, J. B., Huey, L G., Cooper, O. R., Cziczo, D. J., de Gouw, J., Fehsenfeld, F. C., Holloway, J. S., Hübler, G., Lafleur, B. G., Murphy, D. M., Neuman, J. A., Nicks Jr., D. K., Orsini, D. A., Parrish, D. D., Ryerson, T. B., Tanner, D. J., Warneke, C., Weber, R. J., and Wilson, J. C.: Particle characteristics following cloud-modified transport from Asia to North America, J. Geophys. Res., 109, D23S26, doi:10.1029/2003JD004198, 2004. Chin, Mian, Diehl, T., Ginoux, P., and Malm, W.: Intercontinental transport of pollution and dust aerosols: implications for regional air quality, Atmos. Chem. Phys., 7, 5501–5517, 2007. Cooper, O. R., Forster, C., Parrish, D., Trainer, M., Dunlea, E., Ryerson, T., Hübler, G., Fehsenfeld, F., Nicks, D., Holloway, J., de Gouw, J., Warneke, C., Roberts, J. M., Flocke, F., and Moody, J.: A case study of trans-Pacific warm conveyor belt transport: The influence of merging airstreams on trace gas import to North America, J. Geophys. Res., 109, D23S08, doi:10.1029/2003JD003624, 2004. Duck, T. J., Firanski, B. J., Millet, D. B., Goldstein, A. H., Allan, J., Holzinger, R., Worsnop, D. R., White, A. B., Stohl, A., Dickinson, C. S., van Donkelaar, A.: Transport of forest fire emissions from Alaska and the Yukon Territory to Nova Scotia during summer 2004, J. Geophys. Res.-Atmos., 112, D10S44, doi:10.1029/2006JD007716, 2007. Dunlea, E. J., DeCarlo, P. F., Aiken, A. C., Kimmel, J. R., Peltier, R. E., Weber, R. J., Tomlison, J., Collins, D. R., Shinozuka, Y., McNaughton, C. S., Howell, S. G., Clarke, A. D., Emmons, L. K., Apel, E. C., Pfister, G. G., van Donkelaar, A., Martin, R. V., Millet, D. B., Heald, C. L., and Jimenez, J. L.: Evolution of Asian aerosols during transpacific transport in INTEX-B, Atmos. Chem. Phys. Discuss., 8, 15 375–15 461, 2008. Fairlie, D. T., Jacob, D. J., and Park, R. J.: The impact of transpacific transport of mineral dust in the United States, Atmos. Environ., 41, 1251–1266, 2007. Gong, S. L., Zhang, X. Y., Zhao, T. L., Zhang, X., McKendry, I. G., and Zhao, C. S.: A Simulated Climatology of Asian Dust Aerosol and its Trans-Pacific Transport 2. Interannual Variability and Climate Connections, J. Climate, 19, 104–122, 2006. Hacker, J. P., McKendry, I. G., and Stull, R. B.: Modeled downward transport of Asian dust over Western North America during April 1998, J. Appl. Meteorol., 40, 1617–1628, 2001. Heald, C. L., Jacob, D. J., Park, R. J., Alexander, B., Fairlie, T. D., Yantosca, R. M., and Chu, D. A.,: Transpacific transport of Asian anthropogenic aerosols and its impact on surface air quality in the United States, J. Geophys. Res., 111, D14310, doi:10.1029/2005JD006847, 2006. Holzer, M., McKendry, I. G., and Jaffe, D. A.: Springtime Trans-Pacific atmospheric transport from East Asia: A transit-time-PDF approach, J. Geophys. Res., 108(D22), 4708, doi:10.1029/2003JD003558, 2003. Holzer, M., Hall, T. M., and Stull, R. B.: Seasonality and weather-driven variability of trans – Pacific transport, J. Geophys. Res., 110, D23103, doi:10.1029/2005JD006261, 2005. Husar, R. B., Tratt, D. M., Schichtel, B. A., Falke, S. R., et al.: The Asian Dust Events of April 1998, J. Geophys. Res., 106, 18 317–18 333, 2001. Jacob, D., Logan, J. A., and Murti, P. P.: Effect of Rising Asian Emissions on Surface Ozone in the United States, Geophys. Res. Lett., 26(14), 2175–2178, 1999. Jaffe, D., McKendry, I., Anderson, T., and Price, H.: Six `New' Episodes of Trans-Pacific Transport of Air Pollutants, Atmos. Environ., 37(3), 391–404, 2003. Jaffe, D. A., Anderson, T., Covert, D., Kotchenruther, R., Trost, B., Danielson, J., Simpson, W., Berntsen, T., Karlsdottir, S., Blake, D., and Harris, J.: Carmichael G. and Uno I.: Transport of Asian Air Pollution to North America, Geophys. Res. Lett., 26, 711–714, 1999 Jaffe, D., Snow, J., and Cooper, O.: The April 2001 Asian dust events: Transport and substantial impact on surface particulate matter concentrations across the United States, EOS Transactions, 84(46), 501–507, 2003. Jaffe, D., Tamura, S., and Harris, J.: Seasonal cycle and composition of background fine particles along the west coast of the US, Atmos. Environ., 39, 297–306, 2005. Jayne, J. T., Leard, D. C., Zhang, X., Davidovits, P., Smith, K. A., Kolb, C. E., and Worsnop, D. R.: Development of an aerosol mass spectrometer for size and composition analysis of submicron particles, Aerosol Sci. Tech., 33, 49–70, 2000. Leaitch, W. R., Macdonald, A. M., Anlauf, K. G., Liu, P. S. K., Toom-Sauntry, D., Li, S.-M., Liggio, J., Hayden, K., Wasey, M. A., Russell, L. M., Takahama, S., Liu, S., van Donkelaar, A., Duck, T., Martin, R. V., Zhang, Q., Sun, Y., McKendry, I., and Cubison, M.: Evidence for Asian Dust Effects from Aerosol Plume Measurements during INTEX-B 2006 near Whistler, BC, Atmos. Chem. Phys. Discuss., accepted, 2008. Li-Jones, X. and Prospero, J. M.: Variations in the size distribution of non-sea-salt sulfate aerosol in marine boundary layer at Barbados: Impact of African dust, J. Geophys. Res., 103(D13), 16 073–16 084, 1998. Liu, P. S. K., Deng, R., Smith, K. A., Williams, L. R., Jayne, J. T., Canagaratna, M. R., Moore, K., Onasch, T. B., Worsnop, D. R., and Deshler, T.: Transmission Efficiency of an Aerodynamic Focusing Lens System: Comparison of Model Calculations and Laboratory Measurements for the Aerodyne Aerosol Mass Spectrometer, Aerosol Sci. Tech., 41, 721–733, 2007. Macdonald, A. M., Anlauf, K. G., Leaitch, W. R., and Chan, E.: Interannual variability of ozone and carbon monoxide at the Whistler high elevation site, 2002–2006, in preparation, 2008. Macdonald, A. M., Anlauf, K. G., and Leaitch, W. R.: Multi-year characterization of particles at a high elevation Pacific site, in preparation, 2008. McKendry, I. G., Hacker, J. P., Stull, R., Sakiyama, S., Mignacca, D., and Reid, K.: Long range transport of Asian dust to the Lower Fraser Valley, British Columbia, Canada, J. Geophys. Res., 106(D16), 18 361–18 370, 2001. McKendry, I. G., Strawbridge, K., O'Neill, N., Macdonald, A. M., Liu, P., Jaegle, L., Jaffe, D., Fairlie, D., Anlauf, K., and Westphal, D.: A Case of Trans-Pacific Transport of Saharan Dust to Western North America, J. Geophys. Res., 112, D01103, doi:10.1029/2006JD007129, 2007. Ohara, T., Akimoto, H., Kurokawa, J., Horii, N., Yamaji, K., Yan, X., and Hayasaka, T.: An Asian emission inventory of anthropogenic emission sources for the period 1980–2020, Atmos. Chem. Phys., 7, 4419–4444, 2007. Peltier, R. E., Hecobian, A. H., Weber, R. J., Stohl, A., Atlas, E. L., Riemer, D. D., Blake, D. R., Apel, E., Campos, T., and Karl, T.: Investigating the sources and atmospheric processing of fine particles from Asia and the Northwestern United States measured during INTEX B, Atmos. Chem. Phys., 8, 1835–1853, 2008. Prospero, J. M., Ginoux, P., Torres, O., Nicholson, S., and Gill, T.: Environmental Characterization of Global Sources of Atmospheric Soil Dust Identified with the NIMBUS7 Total Ozone Mapping Spectrometer (TOMS) Absorbing Aerosol Product, Rev. Geophys., 40, 1, 1002, doi:10.1029/2000RG000095, 2002. Stohl, A., Eckhardt, S., Forster, C., James, P., and Spichtinger, N.: On the pathways and timescales of intercontinental air pollution transport, J. Geophys. Res., 107(D23), 4684, doi:10.1029/2001JD001396, 2002. Strapp, J. W., Leaitch, W. R., and Liu, P. S. K.: Hydrated and dried aerosol size distribution measurements from the Particle Measuring Systems FSSP-300 probe and the de-iced PCASP-100X probe, J. Atmos. Oceanic Technol., 9, 548–555, 1992. Streets, D. G. and Waldhoff, S. T.: Present and future emissions of air pollutants in China: SO2, NOx, and CO, Atmos. Environ., 34, 363–374, 2000. Sun, Y., Zhang, Q., MacDonald, A. M., Hayden, K., Li, S.-M., Liggio, J., Liu, P. S. K., Anlauf, K. G., Steffen, A., Leaitch, W. R., Cubison, M., Worsnop, D., van Donkelaar, A., and Martin, R. V.: Size-resolved aerosol chemistry on Whistler Mountain, Canada with a high-resolution aerosol mass spectrometer during INTEX-B, Atmos. Chem. Phys. Discuss., accepted, 2008. Thulasiraman, S., O'Neill, N. T., Royer, A., Holben, B. N., Westphal, D. L., and McArthur, L. J. B.: Sunphotometric observations of the 2001 Asian dust storm over Canada and the U.S., Geophys. Res. Lett. 29(8), 1255, doi:10.1029/2001GL014188, 2002. Tratt, D. M., Frouin, R. J., and Westphal, D. L.: April 1998 Asian Dust event: a southern California perspective, J. Geophys. Res., 106, 18 371–18 379, 2001. VanCuren, R. A.: Asian aerosols in North America: Extracting the chemical composition and mass concentration of the Asian continental aerosol plume from long-term aerosol records in the western United States, J. Geophys. Res., 108(D20), 4623, doi:10.1029/2003JD003459, 2003 Van Curen, R. A. and Cahill, T. A.: Asian Aerosols in North America: Frequency and Concentration of fine dust, J. Geophys. Res., 107, 4804, doi:10.1029/2002JD002204, 2002. van Donkelaar, A., Martin, R. V., Leaitch, W. R., Macdonald, A. M., Walker, T. W., Streets, D. G., Zhang, Q., Dunlea, E. J., Jimenez, J. L., Dibb, J. E., Huey, L. G., Weber, R., and Andreae, M. O.: Analysis of aircraft and satellite measurements from the Intercontinental Chemical Transport Experiment (INTEX-B) to quantify long-range transport of East Asian sulfur to Canada, Atmos. Chem. Phys., 8, 2999–3014, 2008. Walker, T. W., Martin, R. V., van Donkelaar, A., Leaitch W. R., Macdonald, A. M., Anlauf, K., Cohen, R. C., Huey, G., Avery, M., Weinheimer, A., Flocke, F., Tarasick, D., Thompson, A., Streets, D. G., Ziemke, J., Bucsela, E., and Celarier, E.: Trans-Pacific transport of reactive nitrogen and ozone to Canada during spring, Atmos. Chem. Phys. Discuss., in preparation, 2008. Zhang, L., Jacob, D. J., Boersma, K. F., Jaffe, D. A., Olson, J. R., Bowman, K. W., Worden, J. R., Thompson, A. M., Avery, M. A., Cohen, R. C., Dibb, J. E., Flock, F. M., Fuelberg, H. E., Huey, L. G., McMillan, W. W., Singh, H. B., and Weinheimer, A. J.: Transpacific transport of ozone pollution and the effect of recent Asian emission increases on air quality in North America: an integrated analysis using satellite, aircraft, ozonesonde, and surface observations, Atmos. Chem. Phys., 8, 6117–6136, 2008. Zhao, T. L., Gong, S. L., Zhang, X. Y., McKendry, I. G., and Zhou, Z. J.: A Simulated Climatology of Asian Dust Aerosol and its Trans-Pacific Transport 1. Mean climate and validation, J. Climate, 19(1), 88–103, 2006. Zhao, T. L., Gong, S. L., Zhang, X. Y., and Jaffe, D. A.: Asian dust storm influence on North American ambient PM levels: observational evidence and controlling factors, Atmos. Chem. Phys., 8, 2717–2728, 2008. Zhou, C. H., Gong, S. L., Zhang, X. Y., Wang, Y. Q., Niu, T., Liu, H. L., Zhao, T. L., Yang, Y. Q., and Hou, Q.: Development and evaluation of an operational SDS forecasting system for East Asia: CUACE/Dust, Atmos. Chem. Phys., 8, 787–798, 2008.