Although airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from person-to-person over long distances is currently thought to be unlikely, the current epidemiological evidence suggests that airborne SARS-CoV-2 infection transmission in confined, indoor spaces is plausible, particularly when outdoor airflow rates are low and when face masks are not utilized. We sought to model airborne infection transmission risk assuming five realistic exposure scenarios using previously estimated outdoor airflow rates for 12 New York City nail salons, a published quanta generation rate specific to SARS-CoV-2, as well as the Wells–Riley equation to assess risk under both steady-state and non-steady-state conditions. Additionally, the impact of face mask-wearing by occupants on airborne infection transmission risk was also evaluated. The risk of airborne infection transmission across all salons and all exposure scenarios when not wearing face masks ranged from <0.015% to 99.25%, with an average airborne infection transmission risk of 24.77%. Wearing face masks reduced airborne infection transmission risk to between <0.01% and 51.96%, depending on the salon, with an average airborne infection transmission risk of 7.30% across all salons. Increased outdoor airflow rates in nail salons were generally strongly correlated with decreased average airborne infection transmission risk. The results of this study indicate that increased outdoor airflow rates and the use of face masks by both employees and customers could substantially reduce SARS-CoV-2 transmission in New York City nail salons. Businesses should utilize multiple layers of infection control measures (e.g. social distancing, face masks, and outdoor airflow) to reduce airborne infection transmission risk for both employees and customers.

In 2015, New York State enacted new ventilation regulations to protect employees and clients from exposure to chemicals used in nail salons. This study measured common air pollutants found in nail salons and assessed compliance with ventilation requirements. Area sampling was conducted in 12 nail salons located in New York City for three consecutive days (Thursday, Friday, and Saturday) to measure total volatile organic compounds (TVOCs), methyl methacrylate, toluene, and ethyl acetate concentrations and estimate ventilation rates. Salon characteristics were determined through a walkthrough inspection and survey administered to the manager. The average daily concentration of carbon dioxide and TVOCs across all salons was 1070 ppm [standard deviation (SD) = 440 ppm] and 29 ppm (SD = 25 ppm), respectively. Chemical-specific air sampling showed low to non-detectable levels of the three measured chemicals. Seventy-five percent of the nail salons did not meet general minimum outdoor airflow requirements. Little temporal variation was observed in day-to-day average concentrations of contaminants within salons, indicating uniform exposure during high customer count days. Salons that met the outdoor airflow requirements had twice the average daily customers (83 versus 42) and half the TVOC concentrations compared with salons that did not (33 versus 16 ppm). Nail salons not meeting ventilation requirements tended to have fewer customers and managers that did not understand the essential components of the ventilation system. Data from this study can be used as evidence of reduction in exposure due to compliance with the ventilation requirements.

Genotypic variation among cultivars and accessions from native populations of L. perenne determines the effect of both intraspecific competition and infection by a fungal endophyte. However, in the absence of herbivory, asexual clavicipitaceous endophytes may not be as important to host success in competitive environments as previously thought in this globally important grass species.