The Missoula, Montana PM 2.5 speciation study - Seasonal average concentrations

Tony J. Ward; Raymond F. Hamilton; Garon C. Smith

doi:10.1016/j.atmosenv.2004.07.012

The Missoula, Montana PM _2.5 speciation study - Seasonal average concentrations

Tony J. Ward
, Raymond F. Hamilton
, Garon C. Smith

School of Public and Community Health Sciences

University of Montana

Research output: Contribution to journal › Article › peer-review

16 Scopus citations

Abstract

The city of Missoula, located in a high mountain valley in western Montana, contains one of the largest populations of residents in the entire Rocky Mountain region completely enclosed by mountains. Due to the surrounding topography and meteorological conditions, Missoula often experiences elevated concentrations of PM _2.5. Recently, dry summers have exacerbated August particulate loads by immersing the valley in smoke from forest fires. Through a serendipitous set of circumstances, concentrations of PM _2.5 (including chemical speciation) were measured throughout a yearlong program that captured both traditional urban particulates plus late summer forest fire particulates. This paper presents the results of the yearlong PM _2.5 sampling program in which filter samples were collected over 24-h periods every 12 days at two locations. For the first time, concentrations of the fine fraction were simultaneously measured on the opposite end of the valley in Frenchtown (nearly 18 miles west of Missoula), thus providing information on the dispersive properties of PM _2.5 in an enclosed airshed, and the spatial and seasonal variations within the Missoula Valley. Organic carbon (OC), elemental carbon (EC), trace elements, and ions were determined from the collected PM _2.5 filter samples. The average mass of ambient PM _2.5, as well as concentrations of OC, EC, elements, and ions measured over the entire year (22/3/00-17/3/01) were nearly identical on both sides of the valley. The annual average of PM _2.5 was 15.4 μg m ^-3 at both Missoula's Boyd Park and at Frenchtown, with the highest concentrations of PM _2.5 measured during the summer (26/6/00-18/9/00) and winter (23/12/00-17/3/01) seasons. The summer PM _2.5 measurements were dominated by smoke from regional wildfires in Montana and Idaho, while thermal inversions in the valley contributed to the elevated winter concentrations.

Original language	English
Pages (from-to)	6371-6379
Number of pages	9
Journal	Atmospheric Environment
Volume	38
Issue number	37
DOIs	https://doi.org/10.1016/j.atmosenv.2004.07.012
State	Published - Dec 2004

Funding

The authors would like to thank the Missoula City—County Health Department (Jim Carlson, Ben Schmidt, Shannon Therriault), Montana CHEER (Tony Tweedale, Darrel Geist), the Missoula Air Quality Advisory Council, the Missoula City—County Board of Health, and Smurfit—Stone Container Corporation for funding and assistance with the sampling program. Finally, thanks to Maria Morandi (The University of Texas, Health Science Center at Houston, School of Public Health) for the insight and guidance.

Keywords

Fine fraction
Forest fires
Montana
Particulates
Seasonal variations
Valley air pollution

Access to Document

10.1016/j.atmosenv.2004.07.012

Cite this

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title = "The Missoula, Montana PM 2.5 speciation study - Seasonal average concentrations",

abstract = "The city of Missoula, located in a high mountain valley in western Montana, contains one of the largest populations of residents in the entire Rocky Mountain region completely enclosed by mountains. Due to the surrounding topography and meteorological conditions, Missoula often experiences elevated concentrations of PM 2.5. Recently, dry summers have exacerbated August particulate loads by immersing the valley in smoke from forest fires. Through a serendipitous set of circumstances, concentrations of PM 2.5 (including chemical speciation) were measured throughout a yearlong program that captured both traditional urban particulates plus late summer forest fire particulates. This paper presents the results of the yearlong PM 2.5 sampling program in which filter samples were collected over 24-h periods every 12 days at two locations. For the first time, concentrations of the fine fraction were simultaneously measured on the opposite end of the valley in Frenchtown (nearly 18 miles west of Missoula), thus providing information on the dispersive properties of PM 2.5 in an enclosed airshed, and the spatial and seasonal variations within the Missoula Valley. Organic carbon (OC), elemental carbon (EC), trace elements, and ions were determined from the collected PM 2.5 filter samples. The average mass of ambient PM 2.5, as well as concentrations of OC, EC, elements, and ions measured over the entire year (22/3/00-17/3/01) were nearly identical on both sides of the valley. The annual average of PM 2.5 was 15.4 μg m -3 at both Missoula's Boyd Park and at Frenchtown, with the highest concentrations of PM 2.5 measured during the summer (26/6/00-18/9/00) and winter (23/12/00-17/3/01) seasons. The summer PM 2.5 measurements were dominated by smoke from regional wildfires in Montana and Idaho, while thermal inversions in the valley contributed to the elevated winter concentrations.",

keywords = "Fine fraction, Forest fires, Montana, Particulates, Seasonal variations, Valley air pollution",

author = "Ward, \{Tony J.\} and Hamilton, \{Raymond F.\} and Smith, \{Garon C.\}",

note = "Funding Information: The authors would like to thank the Missoula City—County Health Department (Jim Carlson, Ben Schmidt, Shannon Therriault), Montana CHEER (Tony Tweedale, Darrel Geist), the Missoula Air Quality Advisory Council, the Missoula City—County Board of Health, and Smurfit—Stone Container Corporation for funding and assistance with the sampling program. Finally, thanks to Maria Morandi (The University of Texas, Health Science Center at Houston, School of Public Health) for the insight and guidance.",

year = "2004",

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doi = "10.1016/j.atmosenv.2004.07.012",

language = "English",

volume = "38",

pages = "6371--6379",

journal = "Atmospheric Environment",

issn = "1352-2310",

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AU - Ward, Tony J.

AU - Hamilton, Raymond F.

AU - Smith, Garon C.

N1 - Funding Information: The authors would like to thank the Missoula City—County Health Department (Jim Carlson, Ben Schmidt, Shannon Therriault), Montana CHEER (Tony Tweedale, Darrel Geist), the Missoula Air Quality Advisory Council, the Missoula City—County Board of Health, and Smurfit—Stone Container Corporation for funding and assistance with the sampling program. Finally, thanks to Maria Morandi (The University of Texas, Health Science Center at Houston, School of Public Health) for the insight and guidance.

PY - 2004/12

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N2 - The city of Missoula, located in a high mountain valley in western Montana, contains one of the largest populations of residents in the entire Rocky Mountain region completely enclosed by mountains. Due to the surrounding topography and meteorological conditions, Missoula often experiences elevated concentrations of PM 2.5. Recently, dry summers have exacerbated August particulate loads by immersing the valley in smoke from forest fires. Through a serendipitous set of circumstances, concentrations of PM 2.5 (including chemical speciation) were measured throughout a yearlong program that captured both traditional urban particulates plus late summer forest fire particulates. This paper presents the results of the yearlong PM 2.5 sampling program in which filter samples were collected over 24-h periods every 12 days at two locations. For the first time, concentrations of the fine fraction were simultaneously measured on the opposite end of the valley in Frenchtown (nearly 18 miles west of Missoula), thus providing information on the dispersive properties of PM 2.5 in an enclosed airshed, and the spatial and seasonal variations within the Missoula Valley. Organic carbon (OC), elemental carbon (EC), trace elements, and ions were determined from the collected PM 2.5 filter samples. The average mass of ambient PM 2.5, as well as concentrations of OC, EC, elements, and ions measured over the entire year (22/3/00-17/3/01) were nearly identical on both sides of the valley. The annual average of PM 2.5 was 15.4 μg m -3 at both Missoula's Boyd Park and at Frenchtown, with the highest concentrations of PM 2.5 measured during the summer (26/6/00-18/9/00) and winter (23/12/00-17/3/01) seasons. The summer PM 2.5 measurements were dominated by smoke from regional wildfires in Montana and Idaho, while thermal inversions in the valley contributed to the elevated winter concentrations.

AB - The city of Missoula, located in a high mountain valley in western Montana, contains one of the largest populations of residents in the entire Rocky Mountain region completely enclosed by mountains. Due to the surrounding topography and meteorological conditions, Missoula often experiences elevated concentrations of PM 2.5. Recently, dry summers have exacerbated August particulate loads by immersing the valley in smoke from forest fires. Through a serendipitous set of circumstances, concentrations of PM 2.5 (including chemical speciation) were measured throughout a yearlong program that captured both traditional urban particulates plus late summer forest fire particulates. This paper presents the results of the yearlong PM 2.5 sampling program in which filter samples were collected over 24-h periods every 12 days at two locations. For the first time, concentrations of the fine fraction were simultaneously measured on the opposite end of the valley in Frenchtown (nearly 18 miles west of Missoula), thus providing information on the dispersive properties of PM 2.5 in an enclosed airshed, and the spatial and seasonal variations within the Missoula Valley. Organic carbon (OC), elemental carbon (EC), trace elements, and ions were determined from the collected PM 2.5 filter samples. The average mass of ambient PM 2.5, as well as concentrations of OC, EC, elements, and ions measured over the entire year (22/3/00-17/3/01) were nearly identical on both sides of the valley. The annual average of PM 2.5 was 15.4 μg m -3 at both Missoula's Boyd Park and at Frenchtown, with the highest concentrations of PM 2.5 measured during the summer (26/6/00-18/9/00) and winter (23/12/00-17/3/01) seasons. The summer PM 2.5 measurements were dominated by smoke from regional wildfires in Montana and Idaho, while thermal inversions in the valley contributed to the elevated winter concentrations.

KW - Fine fraction

KW - Forest fires

KW - Montana

KW - Particulates

KW - Seasonal variations

KW - Valley air pollution

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