Road tunnel-derived coarse, fine and ultrafine particulate matter: physical and chemical characterization and pro-inflammatory responses in human bronchial epithelial cells

Table 4 Elemental carbon (EC) and organic carbon (OC) levels, of road tunnel PM

Sample name (PM)	Size fraction	OC (Hg/mg PM)	EC (Hg/mg PM)
Marienborg, dry conditions	Coarse	104 ± 13	0.3 ± 0.6
	Fine	441 ± 110	4.3 ± 9.6
	Ultrafine	431 ± 107	1.8 ± 1.3
Marienborg, humid conditions	Coarse	157 ± 42	0.7 ± 0.8
	Fine	575 ± 60	0.0 ± 0.0
	Ultrafine	527 ± 38	119.8 ± 112.2
Hell, dry conditions	Coarse	28 ± 10	0.0 ± 0.0
	Fine	94 ± 37	0.0 ± 0.0
	Ultrafine	131 ± 29	0.0 ± 0.0
Hell, humid conditions	Coarse	98 ± 19	0.3 ± 0.5
	Fine	485 ± 14	0.0 ± 0.0
	Ultrafine	434 ± 32	3.2 ± 5.5
Marienborg, after cleaning humid conditions	Coarse	144 ± 17	0.7 ± 0.6
	Fine	483 ± 73	0.0 ± 0.0
	Ultrafine	69 ± 23	0.3 ± 0.5
Hell, after cleaning dry conditions	Coarse	55 ± 7	0.0 ± 0.0
	Fine	76 ± 6	0.4 ± 0.6
	Ultrafine	151 ± 29	2.6 ± 3.5

The table includes the coarse, fine and ultrafine PM sampled from two road tunnels during both humid and dry road surface conditions, and after road surface cleaning. EC and OC levels were determined by thermal optical analysis as described in “Materials and methods”, and presented as µg/mg PM. The data represent the mean ± SEM of 3 analyses

ISSN: 1743-8977