This study targets adult patients between the ages of 19 and 60 who were diagnosed with allergic rhinitis caused by indoor inhalation antigens. Patients with moderate to severe and persistent allergic rhinitis who continue to require medication such as antihistamines and nasal spray steroids for allergic rhinitis are the subjects of this study. Patients who participate in the study will install air purifiers for a certain period of time and observe the objective and subjective improvement of rhinitis symptoms. The study is conducted on two separate occasions for four weeks, and there is a two-week period between the two periods of no use of air purifiers. There are two types of air purifiers: 1)It is an air purifier with a HEPA filter and a VOC filter, and 2) a fake air purifier without air cleaning function. Subjects are divided into Group A and Group B. Group A will receive a fake air purifier, and Group B will be assigned an air purifier with a HEPA + VOC collecting filter. After using the assigned air purifier for the first four weeks, you will have a period of not using it for two weeks, and then replace the air purifiers with each other and use it again for four weeks. When you first assign an air purifier, you will receive an air purifier with a certain filter It is randomly assigned without knowing whether both the researcher and the patient will receive a regular period. During the study period, patients need to visit three times, including when registering for the study, and the study period is screened It will take about 5 months from the end of the air purifier operation