Particulate matter components and subclinical atherosclerosis: common approaches to estimating exposure in a Multi-Ethnic Study of Atherosclerosis cross-sectional study

Table 3 Distribution of PM _2.5 and PM _2.5 component concentrations (μg/m ³ ) by three estimation approaches

Approach	PM_2.5		EC		OC		Silicon		Sulfur
Approach	Median	IQR	Median	IQR	Median	IQR	Median	IQR	Median	IQR
Nearest monitor	13.66	2.340	1.36	0.825	1.93	0.62	0.11	0.074	1.30	0.409
Inverse-distance weighting (IDW)	13.69	1.314	1.32	0.570	1.92	0.31	0.12	0.039	1.26	0.425
City-wide average	13.57	1.143	1.32	0.509	2.05	0.26	0.11	0.031	1.24	0.435

*PM_2.5, particulate matter less than or equal to 2.5 μm in aerodynamic diameter; EC, elemental carbon; OC, organic carbon.

ISSN: 1476-069X