Pollen allergies, pollution and climate: Literature review

The aim of this paper is to synthesize the knowledge on the relations between pollen allergies, climate and air pollution. If pollen allergy has a clear genetic basis, it results of complex interactions with environment, especially climate and pollution, and it has highly increased since the beginning of the 20th century. Interactions with pollution are numerous: air pollutants can increase the number of allergens inside pollen grains and their ability to be released in the atmosphere, as shown by different experiences, and thus increase their allergenicity. In addition, some pollutants act as irritants for the airways and they decrease the bronchial reactivity to pollens. Their action can be reinforced by meteorological conditions, mainly when the same parameters favour both production and dispersion of pollen and pollutants. Climate warming can act by modifying the distribution areas of plants producing allergenic pollen, by extending the blossom season, by increasing the pollen amounts produced by the flowers and by modifying the allergenic content of pollen grains. The effects of air pollution and climate change, which can act separately or in synergy, require an adaptation of the population by preventive measures such as medical and behavioural ones, needing detailed forecasts for the future pollen seasons. (C) 2011 Elsevier Masson SAS. All rights reserved.