Contrasts in oxidative potential and other particulate matter characteristics collected near major streets and background locations.
BACKGROUND
Measuring the oxidative potential of airborne particulate matter (PM) may provide a more health-based exposure measure by integrating various biologically relevant properties of PM into a single predictor of biological activity.


OBJECTIVE
We aimed to assess the contrast in oxidative potential of PM collected at major urban streets and background locations, the associaton of oxidative potential with other PM characteristics, and the oxidative potential in different PM size fractions.


METHODS
Measurements of PM with aerodynamic diameter ≤ 10 μm (PM10), PM with aerodynamic diameter ≤ 2.5 μm (PM2.5), soot, elemental composition, and oxidative potential of PM were conducted simultaneously in samples from 8 major streets and 10 urban and suburban background locations in the Netherlands. Six 1-week measurements were performed at each location over a 6-month period in 2008. Oxidative potential was measured as the ability to generate hydroxyl radicals in the presence of hydrogen peroxide in all PM10 samples and a subset of PM2.5 samples.


RESULTS
The PM10 oxidative potential of samples from major streets was 3.6 times higher than at urban background locations, exceeding the contrast for PM mass, soot, and all measured chemical PM characteristics. The contrast between major streets and suburban background locations was even higher (factor of 6.5). Oxidative potential was highly correlated with soot, barium, chromium, copper, iron, and manganese. Oxidative potential of PM10 was 4.6 times higher than the oxidative potential of PM2.5 when expressed per volume unit and 3.1 times higher when expressed per mass unit.


CONCLUSIONS
The oxidative potential of PM near major urban roads was highly elevated compared with urban and suburban background locations, and the contrast was greater than that for any other measured PM characteristic.
Institute for Risk Assessment Sciences, Division Environmental Epidemiology, Utrecht University, Utrecht, the Netherlands. j.m.c.boogaard@uu.nl
Hanna
H
Boogaard
Nicole A H
NA
Janssen
Paul H
PH
Fischer
Gerard P A
GP
Kos
Ernie P
EP
Weijers
Flemming R
FR
Cassee
Saskia C
SC
van der Zee
Jeroen J
JJ
de Hartog
Bert
B
Brunekreef
Gerard
G
Hoek
D000393:Air Pollutants / Q000032:analysis / Q000737:chemistry*; D000704:Analysis of Variance; D002947:Cities; D004578:Electron Spin Resonance Spectroscopy; D004781:Environmental Exposure / Q000032:analysis*; D004784:Environmental Monitoring; D006801:Humans; D009426:Netherlands; D010084:Oxidation-Reduction; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis / Q000737:chemistry*; D012111:Residence Characteristics; D012621:Seasons; D013052:Spectrometry, X-Ray Emission
D000393:Air Pollutants; D052638:Particulate Matter