Existing evidence is scarce concerning
the various effects of different
PM sizes and chemical constituents on blood lipids. A panel study
that involved 88 healthy college students with five repeated measurements
(440 blood samples in total) was performed. We measured mass concentrations
of particulate matter with diameters ≤ 2.5 μm (PM2.5), ≤1.0 μm (PM1.0), and ≤0.5
μm (PM0.5) as well as number concentrations of particulate
matter with diameters ≤ 0.2 μm (PN0.2) and
≤0.1 μm (PN0.1). We applied linear mixed-effect
models to assess the associations between short-term exposure to different
PM size fractions and PM2.5 constituents and seven lipid
metrics. We found significant associations of greater concentrations
of PM in different size fractions within 5 days before blood collection
with lower high-density lipoprotein cholesterol (HDL-C) and apolipoprotein
A (ApoA1) levels, higher apolipoprotein B (ApoB) levels, and lower
ApoA1/ApoB ratios. Among the PM2.5 constituents, we observed
that higher concentrations of tin and lead were significantly associated
with decreased HDL-C levels, and higher concentrations of nickel were
associated with higher HDL-C levels. Our results suggest that short-term
exposure to PM in different sizes was deleteriously associated with
blood lipids. Some constituents, especially metals, might be the major
contributors to the detrimental effects.