id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-288758-onis9xmo	Peng, Z.	Exhaled CO2 as COVID-19 infection risk proxy for different indoor environments and activities	2020-09-10		.txt	text/plain	3167	191	58	Contrary to some earlier recommendations setting a single indoor CO2 threshold, we show that the CO2 level corresponding to a given infection risk varies by over 2 orders of magnitude for different environments and activities. Although large uncertainties, mainly from virus exhalation rates, are still associated with our infection risk estimates, our study provides more specific and practical recommendations for low-cost CO2-based indoor infection risk monitoring. In this study, we derive the analytical expressions of the probability of indoor COVID-19 infection through room-level aerosol transmission only (i.e., assuming social distance is kept so that close proximity aerosol and droplet pathways are eliminated; fomite transmission is not included), human-exhaled CO2 concentration, and subsequently a few CO2-based quantities as infection risk proxies. where N is number of occupants, Ep is the SARS-CoV-2 exhalation rate by an infector (quanta h -1 ), mex mask filtration efficiency for exhalation, V indoor environment volume (m 3 ), and λ firstorder virus loss rate coefficient (h -1 ) that includes the ventilation with outdoor air and all other virus removal and deactivation processes.	./cache/cord-288758-onis9xmo.txt	./txt/cord-288758-onis9xmo.txt