Cars running without an effective cabin filter can subject occupants to as much as six times more pollutants than those to which a pedestrian standing at the roadside is exposed, according to Bosch. Launching a July 1 to September 30 promotion, the company says the conclusion of a study carried out by air quality experts enlisted by the Department of the Environment, Transport and the Regions, provides garages with an irrefutable sales pitch for replacement cabin filters.

Bosch adds that few drivers are aware that the typical car cabin filter - designed to protect occupants from airborne pollen, particulates, sulphur dioxide, nitrogen oxides and dioxides, lead, benzene, butadiene, carbon monoxide, ozone, volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons - is only effective for about 9000 miles.

“If there were a ready made sales argument for cabin filters, this is it,” says Bosch product manager Paula Santos. “Garages and workshops which make customers aware of the statistics should be able to make excellent profit on cabin filters this summer.”

Bosch Active Carbon cabin filters are designed to absorb up t90 per cent of toxic gases, even in concentrated conditions such as traffic jams and tunnels. Businesses that take a supply of 100 Bosch filters during the promotion will be offered a free display stand, 50 air fresheners and 50 400ml packs of screen wash.