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

Table 3 Oxidative potential (OP) of road tunnel PM

Sample name (PM)	Size fraction	OP^DTT (nmol DTT/ng*min)	OP^ESR (arbitrary units)
Marienborg dry conditions	Coarse	0.063	63,823
	Fine	0.068	78,288
	Ultrafine	0.007	24,389
Marienborg humid conditions	Coarse	0.070	73,555
	Fine	0.060	76,634
	Ultrafine	0.011	24,409
Hell dry conditions	Coarse	0.038	30,161
	Fine	0.043	37,216
	Ultrafine	0.013	13,035
Hell humid conditions	Coarse	0.026	32,764
	Fine	0.054	56,771
	Ultrafine	0.005	9330
Marienborg after cleaning humid conditions	Coarse	0.071	68,176
	Fine	0.062	69,284
	Ultrafine	0.010	26,630
Hell after cleaning dry conditions	Coarse	0.015	16,979
	Fine	0.043	39,594
	Ultrafine	0.026	24,184

Acellular ROS formation was determined by the dithiothreitol (DTT)-method and electron spin resonance (ESR)-method for the coarse, fine and ultrafine PM sampled from two tunnels during both humid and dry road surface conditions, and after road surface cleaning. For the DTT method the positive control was 0.1 and for the ESR the negative control was 2954, and the positive control was 54,119. The results are presented as the mean of three (OP^ERS) and two (OP^DTT) measurements

ISSN: 1743-8977