Molekule is a science and technology company headquartered in San Francisco. It designs and manufactures air purifiers that use photoelectrochemical oxidation (PECO), a technology that the company claims may be useful against chemicals, microbes, allergens, and other forms of air pollution. However, the devices were found to be ineffective in independent product tests by The Wirecutter and Consumer Reports. The Better Business Bureau has asked Molekule to stop a range of claims the company made about the effectiveness of its devices.