TY - JOUR
T1 - Platinum group element concentrations and osmium isotopic composition in urban airborne particles from Boston, Massachusetts
AU - Rauch, Sebastien
AU - Hemond, Harold F.
AU - Peucker-Ehrenbrink, Bernhard
AU - Ek, Kristine H.
AU - Morrison, Gregory M.
PY - 2005/12/15
Y1 - 2005/12/15
N2 - Platinum, Pd, Rh, and Os were found to occur at elevated concentrations in airborne particles (PM10) collected at urban sites in Boston, MA. Average Pt, Pd, Rh, and Os concentrations were 6.9 ± 1.9, 8.1 ± 1.8, 1.50 ± 0.50, and 0.068 (-0.068 + 0.070) pg m-3, respectively. Elevated Pt, Pd, and Rh concentrations are attributed to automobile catalysts, which use Pt, Pd, and Rh for the removal of pollutants from engine exhaust gas. An automobile catalyst source is supported by significant correlations between these elements and by a PVRh similar to that in catalysts. Elevated Os concentrations are also believed to be the result of emission from automobile catalysts in which Os occurs as an impurity. The isotopic composition of Os (187Os/188Os) ranged from 0.30 to 2.90, indicating large variations in Os sources. Osmium has a predominantly anthropogenic origin at concentrations >0.1 pg m-3, whereas natural sources are more important at lower Os concentrations. Osmium isotopic composition also indicates that Pt, Pd, and Rh in Boston air are of almost exclusive anthropogenic origin, with a relatively small natural contribution. Our results indicate that scavenging by rain plays a major role in the atmospheric residence time and environmental fate of PGE.
AB - Platinum, Pd, Rh, and Os were found to occur at elevated concentrations in airborne particles (PM10) collected at urban sites in Boston, MA. Average Pt, Pd, Rh, and Os concentrations were 6.9 ± 1.9, 8.1 ± 1.8, 1.50 ± 0.50, and 0.068 (-0.068 + 0.070) pg m-3, respectively. Elevated Pt, Pd, and Rh concentrations are attributed to automobile catalysts, which use Pt, Pd, and Rh for the removal of pollutants from engine exhaust gas. An automobile catalyst source is supported by significant correlations between these elements and by a PVRh similar to that in catalysts. Elevated Os concentrations are also believed to be the result of emission from automobile catalysts in which Os occurs as an impurity. The isotopic composition of Os (187Os/188Os) ranged from 0.30 to 2.90, indicating large variations in Os sources. Osmium has a predominantly anthropogenic origin at concentrations >0.1 pg m-3, whereas natural sources are more important at lower Os concentrations. Osmium isotopic composition also indicates that Pt, Pd, and Rh in Boston air are of almost exclusive anthropogenic origin, with a relatively small natural contribution. Our results indicate that scavenging by rain plays a major role in the atmospheric residence time and environmental fate of PGE.
UR - http://www.scopus.com/inward/record.url?scp=29244478917&partnerID=8YFLogxK
U2 - 10.1021/es051310q
DO - 10.1021/es051310q
M3 - Article
C2 - 16475323
AN - SCOPUS:29244478917
SN - 0013-936X
VL - 39
SP - 9464
EP - 9470
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 24
ER -
