Walk in green areas. Walk in the woods or among the trees. Author of this file is physicalmap.org. This file is Public Domain. source information on picture : wikiedia.org, "The Power of One Tree - The Very Air We Breathe" - usda.gov Phytoncides are antimicrobial allelochemic volatile organic compounds derived from plants. Phytoncides have strong bactericidal properties and inhibit the growth of viruses or damage them. The topic of the beneficial effects of forest and urban green spaces is further explained in the article "Immerse Yourself in a Forest for Better Health" - dec.ny.gov.