Particulate matter and atherosclerosis: role of particle size, composition and oxidative stress

Table 4 Characteristics of PM fractions

Parameter	Coarse (PM_2.5-10)	Fine (PM_2.5)	Ultrafine
Size (μm)	2.5 - 10	0.15 - 2.5	< 0.15 μm
Number per μm³	+	++	+++
Mass (μg) per μm³	+++	++	+
Relative content (% of total mass) *
Elemental carbon	+	++	+++
Organic carbon	+	++	+++
PAHs	+	+	+++
Metals	+++	++	+
Redox activity	+	++	+++
DTT assay **	+	++	+++
HO-1 induction^#	+	++	+++
GSH depletion ^#	+	+++	+++
Mitochondrial damage^#	None	Some	Extensive
Surface area	+	++	+++
Bioavailability of active compounds	+	++	+++
Lung penetrability	+	++	+++

Modified from Li et al [123]. * Relative content was estimated using mass concentration and fractional composition of CAPs collected on Teflon and quartz filters in two locations from the Los Angeles basin as reported [67]. ** DTT assay was performed on similar CAPs samples [67]. # HO-1 induction, GSH depletion and mitochondrial damage were determined in a murine macrophage cell line (RAW 264.7) and a transformed human bronchial epithelial cell line (BEAS-2B) exposed to similar CAPs samples [67].

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