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This report developed within the ClimAIr project brings together current evidence on the short-term effects of outdoor air pollution on allergic rhinitis. By reviewing published epidemiological studies conducted in different geographical settings and population groups, it describes how variations in ambient air quality are associated with symptom control and healthcare use. The report supports ongoing scientific efforts to better understand the links between air pollution, climate-related factors, and airway allergic diseases.
Air Pollution and Allergic Rhinitis: What Does Current Research Tell Us?
Understanding how environmental factors influence allergic diseases is a central aim of the ClimAIr project. Within this framework, the report “Review article on the effect of air pollution on airway allergy with a focus on vulnerable populations” provides a comprehensive overview of existing evidence on the short-term effects of outdoor air pollution on allergic rhinitis. By synthesising results from multiple epidemiological studies, the review contributes to the project’s overall objective of clarifying how air quality and climate-related factors influence airway allergy outcomes in human populations.
Allergic rhinitis is described in the review as an IgE-mediated inflammatory disease of the upper airways, associated with nasal symptoms and a substantial impact on quality of life and healthcare use.
The Review’s Key Contribution
The main aim of the review was to summarise published scientific studies that examined whether short-term exposure to outdoor air pollutants and climate-related factors is associated with poorer control of symptoms in patients with allergic rhinitis.
Rather than focusing on disease onset, the review specifically addresses short-term changes in symptoms, healthcare visits, or medication occurring within days after variations in environmental exposure.
Methodology
The report conducted a systematic search of the PubMed database and included only original studies involving patients diagnosed with allergic rhinitis, with no age restrictions.
The review focused on studies that:
- Assessed outdoor air pollutants or climate-related factors,
- valuated short-term effects (up to seven days after exposure),
- Reported outcomes related to symptom control or healthcare use.
What did the studies show?
Out of more than 12,000 records initially identified, 30 studies were included in the final analysis. Most of these studies used ecological time-series, case-crossover, cross-sectional, or cohort designs. A large proportion were conducted in China, while others were carried out in Europe and additional regions.
Across different geographical settings, many studies reported that short-term increases in outdoor air pollutant concentrations were associated with worse symptom control or increased healthcare use related to allergic rhinitis. The review notes that younger age, urban residence, and periods with high pollen concentrations were frequently associated with stronger observed effects.
Conclusion
The review concludes that current evidence supports an association between short-term exposure to outdoor air pollution and poorer symptom control in allergic rhinitis. From a public health perspective, the report highlights the importance of integrating air-quality management and climate-adaptation strategies to help mitigate the growing burden of allergic diseases.
The review also identifies key priorities for future research, including the need for multipollutant approaches, longitudinal study designs, more refined exposure metrics, and the use of patient-level data.
Read the full report here >