STATISTICAL CONSIDERATIONS IN THE INTERPRETATION OF SIZE-RESOLVED PARTICULATE MASS DATA

Random measurement error can account for a substantial fraction of the observed variability in coarse particle mass concentrations. This noi se decreases the spatial correlation of coarse particle concentrations , tending to obscure any regional coherence in their variation. It als o works to obscure associations between coarse particles and the effec ts to which they contribute. Multiple regressions can misattribute coa rse effects to fine particles if the fine measurement is sufficiently more precise.