Regional and local determinations of particulate matter and visibility in the southwestern United States during June and July, 1979

Cahill, Thomas A.; Kusko, Bruce H.; Ashbaugh, Lowell L.; Barone, J.B.; Eldred, Robert A.; Walther, F.G.

doi:10.1016/0004-6981(81)90234-1

Cited by 12 publications

(2 citation statements)

References 11 publications

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“…to light extinction has been extensively examined for different U.S. regions and monitoring periods. 24,243,295,412,466,[519][520][521][522][523][524][525][526][527] Highest and lowest chemical extinctions from selected IMPROVE sites shown in Figure 8 are consistent with most of the previous studies and with the average spatial distribution of b ext,p shown in Figure 2. Figure 8a shows that ã 1 deciview difference from 31 deciviews at Great Smoky Mountains National Park to 29.7 deciviews at Shenandoah National Park corresponds to an extinction reduction of 28 Mm -1 , about the same as the total extinction (including clear air) for monitors to the right of Bandelier in Figure associated with exceedances of the PM 10 standard in the Los Angeles area.…”

Section: Table 3 (Cont) Observable Measurement Principle Commentssupporting

confidence: 83%

Visibility: Science and Regulation

Watson

2002

Journal of the Air & Waste Management Association

933

548

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The 1999 Regional Haze Rule provides a context for this review of visibility, the science that describes it, and the use of that science in regulatory guidance. The scientific basis for the 1999 regulation is adequate. The deciview metric that tracks progress is an imperfect but objective measure of what people see near the prevailing visual range. The definition of natural visibility conditions is adequate for current planning, but it will need to be refined as visibility improves. Emissions from other countries will set achievable levels above those produced by natural sources. Some natural events, notably dust storms and wildfires, are episodic and cannot be represented by annual average background values or emission estimates. Sulfur dioxide (SO2) emission reductions correspond with lower sulfate (SO4(2-)) concentrations and visibility improvements in the regions where these have occurred. Non-road emissions have been growing more rapidly than emissions from other sources, which have remained stable or decreased since 1970. Simpler models representing transport, limiting precursor pollutants, and gas-to-particle equilibrium should be used to understand where and when emission reductions will be effective, rather than large complex models that have insufficient input and validation measurements. Examples of model-based source attribution show large differences among estimates from various modeling systems and with ambient measurements.

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Section: Table 3 (Cont) Observable Measurement Principle Commentssupporting

confidence: 83%

Visibility: Science and Regulation

Watson

2002

Journal of the Air & Waste Management Association

933

548

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“…Samples were collected in a slotted rotating drum impactor (Lundgren 1967), a technique in which the UC Davis Air Quality Group and DELTA Group have specialized for the past 30 years (some examples are in Cahill et al 1974Cahill et al , 1981Cahill et al , 1989Flocchini et al 1976;Feeney et al 1975;Barone et al 1978;Flocchini et al 1981;Reid et al 1994;and summarized in Cahill and Wakabayshi 1993) totaling almost 17,000 site days of sampling and analysis, most recently in international studies of aerosol transport (Reid et al 1993;Perry et al 1997Perry et al , 1999 including the large study, ACE-Asia 2001. The present version, an 8 stage rotating drum impactor called a DRUM (Davis Rotatingdrum Unit for Monitoring) was developed (Cahill et al 1985;Raabe et al 1988), modified (O.…”

Section: Sample Collectionmentioning

confidence: 99%

Analysis of Aerosols from the World Trade Center Collapse Site, New York, October 2 to October 30, 2001

Cahill

Cliff

Perry

et al. 2004

Aerosol Science and Technology

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The collapse of the World Trade Center (WTC) buildings #2 (South Tower), #1 (North Tower), and #7 created an enormous collapse pile which emitted intense plumes of acrid smoke and dust until roughly mid-December, when the last spontaneous surface fire occurred. We collected particles by size (8 modes, ≈12 to 0.09 micrometers diameter) and time (typical resolution of 1 to 3 h) from October 2 until late December at the EML 201 Varick Street site roughly 1.8 km NNE of the collapse site and 50 m above ground level. Here we show some of the 70,000 mass and elemental data from the time period October 2 through October 30. Identification of a WTC collapse pile source for aerosols seen at the receptor site were based upon the simultaneous presence of finely powdered concrete, gypsum, and glass with intense very fine combustion mode mass episodes concurrent with winds from the southwest

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