Nissan has launched ion-generating air conditioning in its Japanese market March (Micra) and Cube models.

The so-called Plasmacluster Ion generator produces positive and negative ions from water and oxygen molecules in the air. When these ions encounter airborne microbes, fungi, viruses and airborne pollens in the passenger compartment air, the ions form clusters around the microparticles and react chemically with them, rendering them inactive.

Having cleaned the interior air, clean, the generator releases primarily negative ions to maintain air quality and freshness. These these negative or 'minus' ions are claimed to reduce stress and bring about feelings of happiness by purifying the air, reducing bacteria and decomposing odours.

"Ionising has become a craze in Japan, said a Nissan UK spokesman. "Everything from bin liners to bracelets and hoovers to hair dryers has a 'minus ion' feature. Whilst this technological sensation seems to be unique to Japan, there is no doubt that we could do with a bit of stress release and tranquillity over here, too."