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Introduction & Outline Particulate Measurement 1) PM10 – Particulate Matter < 10 microns

Introduction & Outline Particulate Measurement 1) PM10 – Particulate Matter < 10 microns 2) PM2.5 – Particulate Matter < 2.5 microns - Measured with different instruments. Cache Valley Meteorological Issues Strong winter inversions. Cold. Cache Valley Particulate Issues

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Introduction & Outline Particulate Measurement 1) PM10 – Particulate Matter < 10 microns

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  1. Introduction & Outline • Particulate Measurement • 1) PM10 – Particulate Matter < 10 microns • 2) PM2.5 – Particulate Matter < 2.5 microns • - Measured with different instruments. • Cache Valley Meteorological Issues • Strong winter inversions. • Cold. • Cache Valley Particulate Issues • Organic Carbon (OC) - Wood Burning • Nitrate (NO3) – Mobile Sources/Power Plants • Ammonium (NH4) - Agriculture

  2. S Nocturnal Mountain-Valley Cold Air Drainage Cold Cold Bear Rv. Range Wellsville Mnts. Cache Valley Clear skies promote surface cooling and cold air drainage from mountain slopes. The cold dense air collects and pools in valley bottoms such as the Cache Valley.

  3. Pollutant Trapping Valley Inversion Cache Valley Elevation “Warm” Fog/Clouds Down Valley “Cold” 0 10 30 50 F Wind Direction Wind Speed Temperature Profile of a typical Cache Valley inversion . Coldest air is trapped less then 100 meters above ground. “Strength” of an inversion depends on the Depth of the inversion and the change in temperature within the inversion.

  4. Chemistry & Meteorological Data Sampling • Dates: • • 12/24/01 • • 12/27/01 • • 12/30/01 • • 01/02/02 • • 02/02/02 • • 02/04/02 • • 02/07/02

  5. Meteorological Summary • Winter inversion development. • 8-25 degrees F colder at Logan. • Lighter winds at Logan. Meteorology

  6. Table Summary: Logan: Highest Average [PM10] Logan: Highest Average [OC] Logan: Highest Average [NO3] Logan: Highest Average [NH4] NO3 concentrations & percentage of PM10 are far greater at Logan compared to the other monitors. Units: g/m3 PM10

  7. Units: g/m3 PM10

  8. Table Summary • Logan: Highest Average [PM2.5]. • Logan: Highest Average [NO3]. • Logan: Highest Average [NH4]. • More PM10 at Logan is PM2.5. • Why? • Secondary Formation. Units: g/m3 PM2.5

  9. Figure Summary • PM2.5, NO3, NH4 greater in the Cache Valley Units: g/m3 PM2.5

  10. PM10 and PM2.5 Data Table Summary • Most of Logan PM is PM2.5 • Salt Lake Valley PM contains more primary PM (PM10) • More NO3 & NH4 at Logan

  11. Units: g/m3, Fahrenheit PM10

  12. Meteorology – Chemistry Summary • Inverse Relationship Between: 1) RH & NO3 2) RH & NH4 Why? Rapid particle growth (>10 microns) • Inverse Relationship Between: 1) Temperature & NO3 2) Temperature & NH4 Why? Particle formation physics at cold temperatures.

  13. PM2.5 NH4 : NO3 • Sample Size = 7 • Surplus NH4 (1.6:1.0) • Sample Size = 128 • Surplus NH4 (1.6:1.0) Figure Summary - Cache and Salt Lake Valleys are NOT NH4 limited (excess NH4). - Cache Valley NH4 = Salt Lake Valley NH4 PM2.5

  14. PM10 OC : EC • Sample Size = 7 • Lots of OC (0.18:1.0) • Sample Size = 128 • Lots of OC (0.24:1.0) • Figure Summary • - Organic Carbon dominates in both valleys. • More Organic Carbon in Cache Valley then in Salt Lake Valley. • Equal Elemental Carbon in both valleys. PM10

  15. 4 Conclusions (1) … • Cache Valley PM occurs almost entirely in the PM2.5 size fraction. • More primary PM in the Salt Lake Valley. • OC, NO3, NH4 are higher in the Cache Valley compared to the SLV.

  16. Conclusions (2 & 3) … • “Extreme” cold contributes to: • Ammonium nitrate particulate formation. • Wood smoke contribution in the Cache Valley is likely significant.

  17. Conclusions (4) • Cache Valley has excess Ammonia. - NH4:NO3 = 1.6:1.0 • Target NOx not NH3

  18. Considerations : 1) Logan monitor location. 2) More speciated data.

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