Assessment of the capacity of vehicle cabin air inlet filters to reduce diesel exhaust-induced symptoms in human volunteers

Table 2 Spirometry data before and 1 hour after exposure to filtered air, unfiltered diesel exhaust (DE) and diesel exhaust filtered by filter A and B

	Filtered air			Unfiltered DE			DE + filter A			DE + filter B
	(n = 30)			(n = 28)			(n = 29)			(n = 28)
	Before	1 h after	Delta	Before	1 h after	Delta	Before	1 h after	Delta	Before	1 h after	Delta
FEV₁	4.27 ± 0.66	4.23 ± 0.63	-0.43 ± 0.19	4.30 ± 0.60	4.23 ± 0.58	-0.04 ± 0.1	4.30 ± 0.64	4.27 ± 0.62	-0.02 ± 0.09	4.24 ± 0.64	4.25 ± 0.64	0.01 ± 0.95*
FVC	5.56 ± 1.01	5.48 ± 0.99	-0.07 ± 0.19	5.60 ± 0.91	5.49 ± 0.94	-0.6 ± 0.16	5.62 ± 0.90	5.60 ± 0.93	-0.2 ± 0.26	5.59 ± 0.97	5.52 ± 0.97	-0.05 ± 0.17
FEV₁/FVC	77.45 ± 6.29	77.0 ± 6.80	0.24 ± 2.9	77.29 ± 6.33	78.23 ± 7.39	0.72 ± 2.91	76.84 ± 6.70	76.84 ± 6.71	-0.00 ± 3.54	75.74 ± 6.08	77.57 ± 6.10	1.8 ± 3.82

Data are given as mean ± SD. Paired sample T-test was used to compare means of delta changes (1 hour post minus pre exposure) between exposure to unfiltered DE and filter air, unfiltered DE and DE filtered with filter A, and unfiltered DE with DE filtered with filter B (active charcoal containing filter). A p-value of < 0.05 was considered significant. *P < 0.05.

ISSN: 1476-069X