Special Study -
Coarse Mass Speciation
Background | Data
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To more fully investigate the composition of coarse
particles, a program of coarse particle sampling and speciation analysis
at nine of the IMPROVE sites was initiated between 19 March 2003 and 23
December 2003, with each site operating for one year. Sites were
selected to be representative of the continental United States and were
operated according to IMPROVE protocol analytic procedures.
Data
All data collected as part of the coarse
mass project are available from the
special studies data
page.
The analysis of the coarse mass data was published in Atmospheric
Environment:
Malm, W.C., M.L. Pitchford, C. McDade, and L.L.
Ashbaugh. 2007. Coarse particle speciation at selected locations in the rural
continental United States. Atmospheric Environment, 41 (10):
2225-2239.
Abstract:
A few short-term special studies at National Parks have shown that coarse
mass (CM) (2.5-10 mu m) may not be just crustal minerals but may consist of
a substantial amount (approximate to 40-50%) of carbonaceous material and
inorganic salts such as calcium nitrate and sodium nitrate. To more fully
investigate the composition of coarse particles, a program of coarse
particle sampling and speciation analysis at nine of the Interagency
Monitoring of Protected Visual Environments (IMPROVE) sites was initiated 19
March 2003 and operated through the year 2004. Only the data for 2004 are
reported here. Sites were selected to be representative of the continental
United States and were operated according to IMPROVE protocol analytical
procedures. Crustal minerals (soil) are the single largest contributor to CM
at all but one monitoring location. The average fractional contributions
range from a high of 76% at Grand Canyon National Park to a low of 34% at
Mount Rainier National Park. The second largest contributor to CM is organic
mass, which on an average annual fractional basis is highest at Mount
Rainier at 59%. At Great Smoky Mountains National Park, organic mass
contributes 40% on average, while at four sites organic mass concentrations
contribute between 20% and 30% of the CM. Nitrates are on average the third
largest contributor to CM concentrations. The highest fractional
contributions of nitrates to CM are at Brigantine National Wildlife Refuge,
Great Smoky Mountains, and San Gorgonio wilderness area at 10-12%. Sulfates
contribute less than about 5% at all sites.
