This study aimed to assess the impact of air cleanser on allergic rhinitis patients and indoor air quality. Air cleaners will be installed in the bedrooms and living rooms of the mite allergic rhinitis patients who aged 18-60 years.

Main parameters:

- Symptom medication score of allergic rhinitis

Supportive parameters:

• Visual analog scale of allergic rhinitis
• Quality of life score of allergic rhinitis
• Indoor air quality measurement
• Indoor allergen level measurement

The most important principle in the treatment of allergic diseases is to avoid or reduce exposure to the causative antigen. Causative agents that induce allergic diseases or exacerbate symptoms are classified into indoor and outdoor allergens. House dust mites and pet's hair are typical indoor antigens. Air pollution as well as allergens are important deterioration factors, and environmental management is essential for alleviating symptoms of allergic diseases. Therefore, we are about to evaluate the impact of the air cleaner to the allergic rhinitis patients.

A total of 45 patients will be enrolled in the study and a real air cleaner and a mock-up air cleaner will be randomly installed at ratio of 1: 1 to measure rhinitis symptoms and the changes in indoor air quality after 6 weeks of operation.

Inclusion Criteria:

• Adults between 19 and 65 years of age
• Allergy specialist diagnosis of Moderate to severe persistent allergic rhinitis
• Retrospective Rhinoconjunctivitis total symptom score higher than 7
• Allergy against house dust mite: Skin prick test, with a more than 3 mm wheal, Serum specific IgE higher than 0.35 kUA/L measured by ImmunoCAP
• Who can read and write Korean
• Participants those who voluntarily agreed to this study

Exclusion Criteria:

• Allergy against seasonal allergens (tree, grass, weed pollens)
• Patients with rhinitis due to other causes (drug induced rhinitis or infectious rhinitis etc.)
• Patients with severe anatomical abnormality that may cause nasal blockage such as nasal septum deviation or nasal polyps
• Chronic systemic corticosteroids (≥ 3 months continuous use in past 12 months)
• Participants planning to move or change residence within the study period.
• Staying away from the home continuously for more than 5 days in the study period.
• Having air cleaner previously
• Having indoor smoker
• If pregnancy test is positive or pregnancy is possible during study period.
• Any other reason the participants is deemed unsuitable for participation in clinical trials

Allocation of intervention arm and scoring of symptom and medication scire will be performed by a designated unblinded member of the study staff (i.e. a qualified person who is independent of the protocol-defined study assessments). Once prepared, active air-cleaner and mock device will be identical in appearance. The blinding of all those involved in the evaluation of the study treatment (e.g. physician/nurse as well as the subject) shall be maintained at all times.