On a typical day, most people are indoors about 85% of the time.Because of this, the quality of indoor air is extremely important.Because the prevalence of asthma has increased, increasing attention has been placed on the relationship between indoor pollutants and respiratory diseases. Asian people, including Taiwanese, frequently burn fragrant incense because of their religion and customs in various outdoor as well as indoor environments including homes, stores, shopping plaza, and temples of worship. Burning fragrant incense emits favorable fragrances that can relieve stress and facilitate the attainment of physical, mental, and spiritual balance.Asian people also burn incense to worship gods or their ancestors and in ritual praying for fortune and good luck in temples or their residences.