- If you sneeze suddenly when driving at 50 km/h, you will travel 13 metres without seeing the road. According to the AvD (German Automobile Club - Automobilclub von Deutschland), one in four accidents is caused by the effects of allergies such as sneezing
- Increased levels of dust, soot or micro-organisms in the air can cause driver to suffer from fatigue and lapses in concentration
- Unpleasant odours can occur if dirt particles cannot be absorbed by clogged filters and instead get into the air-conditioning system
- A clogged filter also reduces the blower speed. As a result, windows fog up more quickly leading to restricted visibility
- For that reason the German allergy and asthma association (Deutscher Allergie- und Asthmabund e.V. (DAAB)) recommends that the pollen filter should be replaced every year