A scoping review published in the Annals of Internal Medicine found that only a small fraction of existing studies examined whether air-cleaning technologies “reduce human infections or identify potential harmful emissions.” CIDRAP has the news.
Researchers analyzed 672 primary studies published from 1929 to 2024 “on the effects of engineering infection-control interventions designed to remove viruses from the air.” These technologies include “high-efficiency particulate air (HEPA) filters, germicidal ultraviolet (GUV) lights, ionizers, and advanced filtration systems found in many homes, healthcare facilities, schools, and businesses.”
Of the studies analyzed, “90% evaluated environmental samples only, only 8% included human participants, and 1% were based on sentinel animals.” None of the studies “measured quality of life or functioning, sustainability (e.g., carbon footprint, greenhouse gas emissions), or economic analysis.” 49% of the studies “measured viable harmless microbes from air samples.”
One of the authors wrote that the team was “surprised to find that most of the research tested air cleaning devices in lab chambers, not in real-world settings where people live, work, or go to school.” Another of the coauthors cautioned that “ozone and other chemicals created by some air-cleaning devices can actually harm the respiratory system, especially in children or people with chronic respiratory illnesses.” They called for new studies “that track infections rather than indirect measures like air-particle counts” and the “development of a standard set of health-related outcomes for future research to make findings more comparable and useful for informing public health policy.”
