Most allergy sufferers are atopic. Atopy means that the individual has a genetic tendency to develop allergies. In most developed countries up to 40% of the population will be atopic. Even only one-half of them will develop allergic symptoms. Atopic individuals are genetically prone to manufacture antibodies of the IgE class. These IgE (immunoglobulin E) antibodies tend to react against allergens present in the environment (pollen, cat dander, moulds, house dust mite). Atopy is therefore easily diagnosed in an individual who has a personal or immediate family history of allergies and on doing skin prick test they react to one or more of the common environmental allergens.
It is estimated that around 23 million Europeans suffer some kind of respiratory disorder. A German study has linked increases in hay fever, eczema and asthma in Swedish, Swiss, Danish and Bavarian children have been linked to vehicle exhaust particles. In addition to these self-contained afflictions, there is less resistance to a whole range of infections, symptoms of a weakened immune system.