Evolving understanding of pollutant transport from asia to north america
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Evolving Understanding of Pollutant Transport from Asia to North America. Richard (Tony) VanCuren Research Division, California Air Resources Board Department of Applied Science, UCD WRAP 5-23-06. TransPacific Transport to North America: The contradiction of gas and aerosol data. MOPITT CO

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Evolving Understanding of Pollutant Transport from Asia to North America

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Evolving UnderstandingofPollutant TransportfromAsiatoNorth America

Richard (Tony) VanCuren

Research Division, California Air Resources Board

Department of Applied Science, UCD

WRAP 5-23-06


TransPacific Transport to North America:The contradiction of gas and aerosol data

MOPITT CO

2000

TOMS Aerosol

April15-May6

1998


The April 1998 Asian Dust Storms: a Natural Experiment

Image after Husar, R. B. et al.,

J. Geophys. Res. 106: 18,317 –18,330, 2000.


Asian Dust is UbiquitousAround the Northeastern Pacific

VanCuren & Cahill, 2002


Comparative Frequencies of Asian Dust Across North America


Asian Aerosol Chemistry at Western Cordillera Sampling Sites

  • Two Asian components:

    • Primary - Dust & combustion

    • Mass correlation 0.87 (<2.5um)

    • Secondary - Aged biomass smoke

    • Mass correlation 0.17 (<2.5um)

  • Mean Asian aerosol fraction:

    • 75% of Fines (<2.5 mm dia.)

    • 60% of Total (<10 mm dia.)

  • Principal Components from:

  • 1234 IMPROVE 24-hr filters

  • March - October 1988-1999

  • Crater Lake, OR and Mt. Lassen, CA

VanCuren, 2003


Dusty Asian Plume

Siberian(?) Biomass Smoke

Aerosol Composition March – October(Transport Season)Crater Lake / Mt. Lassen

  • Mean Asian fraction:

    • 75% of Fines (<2.5 mm)

    • 60% of Total (<10 mm)

COARSE

2.9 ± 1.9 mg/m3

FINE

3.8 ± 2.0 mg/m3

OTHER

CARBONACEOUS

SO4=

SOIL

NO3-


ITCT-2K2 Aerosol Sampling Sites


Marine mode

Medium to coarse sea salt

(2-6 mg/m3)

Weak sulfur (.2-.4 mg/m3)

Continental mode

Coarse Si, Fe, Ca, Al, Na, K

Strong fine sulfur (1-2 mg/m3)

Mineral & reacted Na

Weak sea salt (.2-.6 mg/m3)

MARINE 5/19

CONTINENTAL 4/22

Trinidad Head Aerosol Composition Modes


Back Trajectory 4/23/02 - Trinidad Head


Trinidad Head, Trinity Alps, & Mauna Loa Continental Aerosols’Al - Elemental Ratios(Holmes & Zoller, 1996)

Trinidad Head

Trinity Alps


ITCT-2K2 Findings: 1 - Dominant Modes

Concordant Montane AerosolSingle dominant aerosolAsian origin confirmed by soil element profilesConcentration varies but continuously presentMBL Disconnects Coastal Site from Free TroposphereSea salt & local combustion – infrequent tropospheric mixing


ITCT-2K2 Findings: 2 - Air Mass Mixing State

Soil Mixing Model

Air Mass Influence


ITCT-2K2 Findings: 3 - Soil Mixing State

Diurnal oscillation of sources

Coarse - strong local sources and upslope transport

Fine - dominated by tropospheric fumigation


Asian Sources Explain “Anomalous” Regional Aerosol Events

2/24/1996


Regional Aerosol Chemistry:Feb 21 & 24, 1996

2/21/96

2/24/96


Back-trajectories - 2/24/96

Craters of the Moon

Bryce Canyon

Grand Canyon


Sample Global Model Results

  • Cameron-Smith, P. et al., (2005), Impact of Long-Range Dust Transport on Northern California in Spring 2002, Internal Report Lawrence Livermore Lab

  • Holzer, M., T. M. Hall, and R. B. Stull (2005), Seasonality and weather-driven variability of transpacific transport, J. Geophys. Res., 110, D23103, doi:10.1029/2005JD006261.

  • Park, R. J. et al. (2004), Natural and transboundary pollution influences on sulfate-nitrate-ammonium aerosols in the United States: Implications for policy, J. Geophys. Res., 109, D15204, doi:10.1029/2003JD004473.

  • Heald et al. Transpacific transport of Asian anthropogenic aerosols and its impact on surface air quality in the United States, Submitted to J. Geophys. Res.


Cameron-Smith, P. et al., (2005), Impact of Long-Range Dust Transport on Northern California in Spring 2002, Internal Report Lawrence Livermore Lab


Holzer, M., T. M. Hall, and R. B. Stull (2005), Seasonality and weather-driven variability of transpacific transport, J. Geophys. Res., 110, D23103, doi:10.1029/2005JD006261.


Holzer, M., T. M. Hall, and R. B. Stull (2005), Seasonality and weather-driven variability of transpacific transport, J. Geophys. Res., 110, D23103, doi:10.1029/2005JD006261.


Park, R. J., D. J. Jacob, B. D. Field, R. M. Yantosca, and M. Chin (2004), Natural and transboundary pollution influences on sulfate-nitrate-ammonium aerosols in the United States: Implications for policy, J. Geophys. Res., 109, D15204, doi:10.1029/2003JD004473.

“Bulk aerosol measurements from the DC-8 aircraft indicate that 40% of non-sea-salt sulfate (nss-SO4=) on average was incorporated in dust particles [Jordan et al., 2003]….

“The observation shows strong outflow in the 0- to 5-km column. The model also shows an enhancement in that column but is lower than observations by up to a factor of 2.


Heald et al. Transpacific transport of Asian anthropogenic aerosols and its impact on surface air quality in the United States, Submitted to J. Geophys. Res.


Concluding Thoughts

  • The coast ranges and Sierra-Cascade generally prevent Pacific marine boundary layer air from reaching the continental interior of North America.

  • TransPacific Transport is strongest in spring, but occurs year-round.

  • The free troposphere “background” aerosol contains “natural” desert dust, anthropogenic dust, and combustion products from Asia: ¼ soil; ¼ SO4=; 2/5 carbonaceous aerosol.

  • North-westerly winds associated with “clean air corridors” commonly carry Asian aerosols, thus the “clean 20%” in the West is significantly influenced by global pollution levels.

  • At “clean” western IMPROVE sites, as much as 3/4 of PM2.5 and 2/3 of Coarse Particles may come from Asia.

  • Emissions growth and control efforts in Asia may modify visibility in North America.


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