Table 1.

Ambient particulate matter ${\left(\mathrm{PM}\right)}_{2.5}$ and concentrated ambient ${\mathrm{PM}}_{2.5}$ (CAP) in the exposure chambers were collected to Teflon filters weekly, and their elemental compositions were determined by inductively coupled plasma mass spectroscopy (ICP-MS).

Element	CAP		Ambient
	Mean (${\text{ng}/\mathrm{m}}^3$)	SD	Mean (%)	SD
Na	35.14	19.66	11.95	3.24
Mg	8.62	4.81	2.87	0.48
Al	25.93	12.67	2.56	2.41
Si	78.53	39.39	8.53	5.76
P	1.00	0.50	0.18	0.10
S	249.91	183.42	48.31	6.90
K	20.38	11.57	3.19	0.86
Ca	39.30	19.86	5.40	1.86
Ti	3.55	2.09	0.59	0.14
V	0.26	0.15	0.03	0.04
Cr	0.28	0.15	0.07	0.02
Mn	1.19	0.75	0.21	0.03
Fe	47.19	30.10	7.92	0.84
Ni	0.65	0.40	0.11	0.05
Cu	1.45	0.93	0.36	0.10
Zn	13.77	6.82	2.63	1.41
As	0.19	0.10	0.03	0.02
Se	0.13	0.06	0.01	0.02
Br	8.42	5.22	1.42	0.35
Sr	0.24	0.13	0.18	0.05
Ag	0.55	0.19	0.06	0.13
Sn	1.25	0.53	0.19	0.16
Ba	1.66	1.16	0.32	0.23
Ce	0.24	0.25	0.04	0.08
Pr	0.30	0.13	0.04	0.06
Er	0.98	0.75	0.20	0.06
Lu	1.33	1.19	0.32	0.12
W	0.41	0.26	0.12	0.08
Ir	0.11	0.04	0.01	0.02
Pt	0.20	0.09	0.02	0.03
Au	0.22	0.14	0.03	0.03
Hg	0.34	0.05	0.07	0.04
Tl	0.11	0.04	0.01	0.02
Pb	0.93	0.32	0.14	0.04

Note: CAP, concentrated ambient particulate matter ${\left(\mathrm{PM}\right)}_{2.5}$; SD, standard deviation.