Table 3

Rationale for the interrelationship between components of air pollution and allergens in inducing respiratory allergy

Components of air pollution can interact with pollen grains, leading to increased release of antigens characterised by modified allergenicity
Components of air pollution can interact with allergen-carrying paucimicronic particles derived from plants, which are able to reach the peripheral airways with inhaled air, inducing asthma in sensitised subjects
Components of air pollution, especially ozone, particulate matter and sulphur dioxide, have an inflammatory effect on the airways of susceptible subjects, causing increased permeability, easier penetration of pollen allergens in the mucous membranes and easier interaction with cells of the immune system. There is also evidence that predisposed subjects have increased airway reactivity induced by air pollution and increased bronchial responsiveness to inhaled pollen allergens
Components of air pollution, in particular diesel exhaust particles, have an adjuvant immunological effect on immunoglobulin E synthesis in atopic subjects