The strength of the BMW M4 Coupé is evident in every detail.
When the summer sun heats the inside of a car an irritating mix of chemicals and pollutants may be released from the materials inside the cabin. Add pollens sucked in through the car's air conditioning system and driving could become hazardous to your health.
Swedish carmaker Volvo has adopted a "clean inside and out" programme to provide allergy-free cars; every Volvo now has electronic climate control with pollen filters and all the materials used inside the car comply with the international 'Oeko-Tex'² ecological certification to create an allergy-free interior.
Materials such as seat belts, carpets, fascia, glues and fabrics are tested for dyes, pesticides and metals; even the leather in the upholstery is tanned using natural plant substances to eliminate chromium that, together with nickel in buttons and controls, can cause contact allergies.
All the metals fittings in the cabin are also tested for contact allergies, as are the exterior door handles.
Volvo cars (with the exception of the C70 convertible) also have electronic sensors in their air intakes that monitor the pollutants in the incoming air and automatically close when levels rise too high when driving in busy city traffic, traffic jams or tunnels.
A combined filter with active carbon eliminates odours and lowers the levels of nitrogen dioxides, ground-level ozone and hydrocarbons.
The company has an expert "nose team" that sniff-tests all components to be used in Volvo car interiors to make sure they are inoffensive and safe.
Smells intensify as the car interior heats up so the components are heated to replicate a car parked in the sun all day.