The purpose of this study is to determine whether a retrofit particle trap can reduce the adverse vascular responses to diesel exhaust inhalation

18 subjects healthy male volunteers will be recruited at Umeå University. In a randomised, double blind 3 way crossover trial, subjects will be exposed to filtered air, diesel exhaust (300mcg/m3) or filtered diesel exhaust for 1 hour during intermittent exercise.

2 hours following the exposure, thrombogenicity will be assessed using the Badimon chamber - an ex-vivo model of thrombosis formed under constant flow conditions.

Forearm blood flow in response to infused intra-brachial vasodilators will be measured using venous occlusion plethysmography 6 hours after the exposure.

Arterial stiffness will be measured using peripheral arterial applanation tonometry in the hour post-exposure.

Blood samples will be collected at timepoints over the 24 hours after exposure.

Inclusion Criteria:

• Healthy male volunteers

Exclusion Criteria:

• Intercurrent illness
• Smoking
• Significant occupational exposure to air pollution
• Regular medication usage