FIG 1.

Environmental scenarios affecting daily cumulative risks of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure for an indoor and outdoor produce worker. (Left) Daily worker scenarios. Simulations were conducted in which workers were engaged in three overarching environmental scenarios: 2 h of shared transportation to and from work (aerosol exposure only), a 12-h working shift (aerosol, droplet, fomite exposure), and 10 h of private (no exposure) or shared housing (aerosol, droplet, fomite exposure). (Top left) The indoor worker was assumed to travel in the back of an enclosed, midsized car for 2 h total with an infectious symptomatic passenger seated in front of them, allowing for exposure to virus-containing aerosols. During the indoor work shift, the uninfected susceptible and infectious symptomatic worker were assumed to spend 11 h physically distanced (2 m) while working on a conveyor line, with 1 h spent in an indoor breakroom. The indoor worker was assumed to not participate in shared housing. (Bottom left) The outdoor worker was assumed to travel in an enclosed school bus for 2 h total with an infectious symptomatic passenger seated >3 m away from the uninfected susceptible worker, allowing for exposure to virus-containing aerosols. Given the nature of the outdoor work shift, the uninfected susceptible and infectious symptomatic workers were assumed to spend 11 h in close-contact range (1 m) while working in the open-air harvesting field, with 1 h spent on the school bus functioning as a breakroom. The outdoor uninfected susceptible worker was assumed to participate in employer-provided shared housing for 10 h with an infectious symptomatic co-worker. Of the 10 h, it was assumed that the workers would spend 2 h physically distanced (2 m) in the space, while the remaining 8 h would be spent sleeping in the same room (aerosol exposure only). (Right) Scenario quantitative microbial risk assessment (QMRA) model. Each scenario simulates the risk of SARS-CoV-2 infection for an uninfected and susceptible worker after exposure to an infected and symptomatic co-worker across viral transmission (aerosol-, droplet-, and/or fomite-mediated) pathways. Each scenario also quantifies the impact of infection control strategies (red lines), adjusted for the context of each scenario. For example, universal masking (defined as both workers wearing the same type of mask) was applied to both the infected and susceptible worker, increased air exchange and surface disinfection was applied to the modeled environmental scenario, and both the hand hygiene and vaccination interventions were applied to the susceptible worker alone (see Materials and Methods). ACH, air exchange rate.