Objective: Plasma cluster ions consist of positive and negative ions and are known to suppress the activity of total bacteria, mold fungi, viruses and allergens floating in the air. In terms of inactivating mite allergens, it was reported that plasma cluster ions suppressed the symptoms of atopic dermatitis in mice. In the present study we investigated the effect of plasma cluster ions on attenuating chronic allergic rhinitis and fatigue induced by mite allergens in humans.
Design: Sixteen subjects with specific immunoglobulin E (IgE) positive to Dermatophagoides pteronyssinus, who had symptoms of allergic rhinitis caused by house dust participated in a randomized double-blinded crossover trial. Subjects occupied a mite allergen challenge room and performed mental task for 4 hours with 25,000/cm³ plasma cluster ions or without plasma cluster ions and rested for 2 hours outside of the room. We measured mite allergens (Der p1) on the floor using plastic dishes (90 mm diameter) placed at 5 points in the room. We also investigated the symptoms of allergic rhinitis using the Japanese Allergic Rhinitis Standard QOL Questionnaire (JRQLQ) during the 4-hour load and 2-hour rest and performance by Uchida-Kraepelin psychodiagnostic test during the 4-hour load.
Result: Plasma cluster ions inactivated 80–90% of Der p1 and attenuated the symptoms of nasal congestion in JRQLQ. Moreover, plasma cluster ions inhibited fatigue-induced impaired performance in Uchida-Kraepelin psychodiagnostic test compared to the case without the ions.
Conclusion: Plasma cluster ions reduce mite allergens and are effective for attenuating chronic allergic rhinitis and fatigue.

Objective: In the present study, we conducted a clinical study to investigate the effect of newly developed LED lighting on improving sleep quality and living comfort in an indoor environment.
Design: Twelve healthy male subjects, whose Pittsburgh Sleep Quality Index (PSQI) scores were ≥5 participated in a randomized crossover trial. On the first day, as a sleep evaluation period, subjects rested from 21:00 to 22:00 under the newly developed lighting or ordinary lighting, went to bed at 22:00 and got up at 7:00. On the second day, as an evaluation period of daytime use, they performed a mental load for 4 hours under each lighting condition. We evaluated the quality of sleep by SLEEP SCAN and the St. Mary’s Hospital sleep questionnaire, and daytime performance by Uchida-Kraepelin psychodiagnostic test and advanced trail-making test (ATMT).
Result: The newly developed lighting improved the quality of sleep and increased comfortable feelings among participants; moreover, in daytime use, the environment did not induce impaired performance in spite of lower illumination.
Conclusion: This newly developed LED lighting produces suitable illumination and color temperature before sleeping and is useful for improving the living comfort in an indoor environment.