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

Table 1 Pollutant concentrations in the exposure chamber during exposure to filtered air, as well as filtered and unfiltered diesel exhaust challenges

Exhaust component	Filtered air (n = 30)	Unfiltered DE (28)	Diesel exhaust filter A (n = 29)	Diesel exhaust filter B (n = 28)
PM₁ (μg/m³)	4.6 ± 1.7	350 ± 72	183 ± 18***	93 ± 16***
Particle number x 10⁵/cm³	n/a	54 ± 10	30 ± 6*	15 ± 3**
NO (ppm)	0.00 ± 0.00	2.49 ± 1.01	2.21 ± 0.66	1.77 ± 0.55**
NO₂ (ppm)	0.00 ± 0.00	0.68 ± 0.29	0.58 ± 0.20	0.10 ± 0.04***
Hydrocarbons (ppm)	0.00 ± 0.00	2.41 ± 0.81	1.85 ± 0.60*	1.02 ± 0.11***

Data are given as mean ± SD. T-tests were performed to analyze differences in pollutant concentrations between unfiltered DE and DE exhaust after the use of the cabin filters. P values of < 0.05 were considered significant: *P < 0.05, **P < 0.01, ***P < 0.001.

ISSN: 1476-069X