Indoors are still risky.
This is troubling, to me:
One of the problems is that governments and businesses are still spending millions of dollars on surface disinfection, says Jimenez, despite evidence that it is rare for SARS-CoV-2 to pass from one person to another through contaminated surfaces. By contrast, few countries have invested in measures to improve indoor air quality.
Might invest in a CO2 monitor. Pretty cheap on amazon.
I mean, I’m in my tiny office, though overnight I keep the window open.
It’s one of the reasons that Jimenez and others advocate the use of inexpensive CO2 monitors as a rough measure of whether ventilation is adequate or not. As virus-carrying aerosols are exhaled, so too is CO2. And when ventilation is poor, CO2 accumulates along with the virus, says Jimenez. In an unreviewed analysis5, Jimenez and his co-author Zhe Peng found that SARS-CoV-2 infection risk rises along with CO2 concentrations indoors.
Taiwan, Norway and Portugal have laws that limit indoor CO2 to 1,000 p.p.m. Studies in California6 and Madrid7 show that CO2 levels in school classrooms frequently exceed this level. High levels have been linked to poorer mental concentration and more sick days6.
Setting clear CO2 limits would help to ensure that ventilation is adequate to reduce infection risk, says Jimenez. But his work suggests that in general 700 p.p.m. would be a better limit, and lower limits should apply to gyms and other venues where people expel greater volumes of air.