This study will evaluate the effects of RHINIX™ nasal filters on seasonal allergic rhinitis (hay fever) in a park setting.

The study will include 100 participants with grass allergy and will look at the efficacy and usability of RHINIX™ nasal filters on hay fever in a randomized, double-blind, placebo-controlled, crossover design.

Inclusion Criteria:

• History of seasonal allergic rhinitis (SAR) for a minimum of 2 years before study entry. Documented by a positive skin test (wheal > 3mm) within 12 months of study enrolment.
• Written informed consent
• Must be able to complete the study
• Reliable anticonception for fertile women
• FEV1 higher than 70 % of predicted value
• Positive grass IgE blood sample higher or equal to 0,7 kU/L

Exclusion Criteria:

• Improper fit of the Rhinix™ device
• Nasal septal deviation
• Retrospective TNSS for last summer < 3
• Positive pregnancy test for fertile women
• Inadequate washout periods in regards to park study appointments (intranasal or systemic corticosteroids (1month), intranasal cromolyn (2 weeks), intranasal or systemic decongestants (3 days), intranasal or systemic antihistamines (3 days), Loratadine (10 days)).
• Rhinitis medicamentosa
• Use of long acting anti-histamines.
• Documented evidence of acute or cronic sinusitis, as determined by the individual investigator.
• FEV1 lower than 70 % of predicted value
• Subjects with nasal conditions likely to affect the outcome of the study in the opinion of the investigator, i.e. anterior nasal septum deviation, nasal septal perforations, nasal polyps, chronic nasal obstruction or other nasal diseases.
• Receipt of immunotherapy with grass pollen within the previous 10 years (at least two rounds of treatment).
• Women who are breastfeeding