Research SummariesWhen teachers could visualize the carbon dioxide levels in their classrooms, they opened windows and maintained effective air exchanges, which helps prevent COVID-19 transmission. Environmental Research 
This study evaluates ventilation rate schema for respiratory infection control. In contrast to ASHRAE Standard 62.1, it recommends the ventilation rate be a function of distance between occupants and suggests that 21 cfm/person (10 L/s/p) would be a good minimum ventilation standard for respiratory infection control. Indoor Air
Installing activated carbon filters to remove ozone has a good cost-to-benefit ratio, especially in buildings with high occupancy. Indoor Air
Contrary to previous research, this study found that the human body can adapt to high concentrations of pure carbon dioxide (20,000 ppm) without adverse effects. It suggests that some negative health effects at high concentrations cannot be attributed to CO2 but are most likely caused by other pollutants such as bioeffluents (e.g. body odors). Indoor Air
Chemical intolerance may affect one in five people in the U.S. International Journal of Environmental Research and Public Health
Surgical masks are loaded with semivolatile and volatile organic compounds (VOCs) that pose potential health risks. Commonly found chemicals include naphthalene, acrolein, and various PAHs and phthalates. Environmental Science & Technology
Indoor bioaerosol concentrations were not greatly affected by opening windows. Building and Environment
Household characteristics including presence of carpeting, low floor cleaning frequency, older home age, presence of pets, and indoor relative humidity above 45% were positively associated with the presence of multiple indoor biocontaminants such as dust mites, animal dander, bacteria, and mold. Indoor Air
During the heating season, suppling hot air at the ceiling can create thermally stratified conditions that interferes with dilution and reduces the effectiveness of ventilation. Indoor Air
Despite claims of removing VOCs, consumer-grade air purifiers using oxidation had varying degrees of effectiveness, with some being essentially ineffective and others forming by-products. Environmental Science & Technology Letters 
Exposure to essential oil from an ultrasonic diffuser changed cognitive ability in a simulated office setting. Indoor Air | 
