I think the issue (for me) would be an indoor area where a lot of exertion has occurred. The more and deeper you breathe, the more droplets you will generate
There's a fair amount of data out there on survival or aerosols of this coronovirus family. I think the time component of aerosol infectivity is still in the period of understanding, and it certainly depends on the size of the droplet, the temperature at least:
"...airborne coronavirus MERS-CoV exhibited strong capability of surviving, with about 64% of microorganisms remaining infectious 60 min after atomization at 25 °C and 79% relative humidity (RH) (9). On the other hand, rapid virus decay occurred, with only 5% survival over a 60-min procedure at 38 °C and 24% RH, indicative of inactivation. Recent experimental studies have examined the stability of SARS-CoV-2, showing that the virus remains infectious in aerosols for hours (12) and on surfaces up to days". link
"The SARS-CoV-2 virus has been found to remain viable in aerosols for 3 h, while it, in the form of droplets, is more stable on plastic and stainless steel, copper, cardboard, and glass with durations detected up to 72, 4, 24, and 84 h, respectively. In comparison, the SARS-CoV virus was also found to be airborne in the form of aerosols for 3 h, indicating that both SARS viruses behave more or less in the same manner in the air. Nevertheless, the SARS-CoV virus remains stable and viable in the form of droplets on plastic and stainless steel, copper, cardboard, and glass with durations (half-lives) lasting to 72, 8, 8, and 96 h, respectively." link, and the original NEJM paper which shows at least 3h of aerosol data: NEJM