Introduction and objective:
Inhalant allergens, especially pollen grains, are an increasing threat to human health and are the most common cause of allergic rhinitis (AR). The increased prevalence of allergy is also incident to the interaction of various environmental factors. The aim of the study is to demonstrate the effect of climatic conditions, air pollution, and urbanisation on the dynamics of pollen grain production by plants and the increase in their allergenicity.

Review methods:
The literature review was based on selected key words. Scientific publications mainly from the last eight years available in PubMed, PLOS ONE and Google Scholar databases were used.

Brief description of the state of knowledge:
Particulate Matters (PM), ozone O3, and nitrogen oxides NOx may induce changes in the structure of pollen grains, facilitating the release of allergens. Global warming, rising CO2 concentrations, and changing precipitation patterns have a direct impact on plant life cycles and pollen production. An earlier onset and elongation of pollen seasons leads to increased exposure to pollen allergens. Climate changes also favours the occurrence of new allergenic plant species and intensifies the production of pollen grains by existing species. In cities, pollen grains may be more allergenic than in less urbanised areas.

Summary:
Environmental changes and air pollution significantly impact the allergenicity of pollen grains. The increased allergen production and modifications of their structure result in an increased risk of developing pollinosis and an intensification of allergic symptoms. Understanding these mechanisms is key to developing more effective treatments and prevention of pollen allergies, which is an important aspect of public health.