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

Table 2 Endotoxin levels of road tunnel PM

Sample name (PM)	Size fraction	Endotoxins (EU/mg PM) mean ± SD
Marienborg, dry conditions	Coarse	0.29 ± 0.16
	Fine	0.24 ± 0.15
	Ultrafine	0.20 ± 0.08
Marienborg, humid conditions	Coarse	0.69 ± 0.36
	Fine	0.17 ± 0.08
	Ultrafine	0.19 ± 0.08
Hell, dry conditions	Coarse	0.61 ± 0.29
	Fine	0.25 ± 0.13
	Ultrafine	0.09 ± 0.09
Hell, humid conditions	Coarse	0.39 ± 0.26
	Fine	0.32 ± 0.18
	Ultrafine	0.43 ± 0.12
Marienborg, after cleaning humid conditions	Coarse	0.64 ± 0.37
	Fine	0.67 ± 0.35
	Ultrafine	0.84 ± 0.33
Hell, after cleaning dry conditions	Coarse	0.59 ± 0.37
	Fine	0.70 ± 0.44
	Ultrafine	0.42 ± 0.25

The table includes the coarse, fine and ultrafine PM from two tunnels sampled during both humid and dry road surface conditions, and after road surface cleaning. Endotoxin levels were determined by the LAL-method, as described in “Materials and methods”. The data are presented as the mean ± SEM of three analyses of the endotoxin levels

ISSN: 1743-8977