Thread by @DrEricDing

🏒HOCKEY RINK AEROSOL—new study shows stagnant smoke sits 10 feet above a hockey rink. Cool air near the ice and warmer air above create a thermal inversion—restricts air movement from ice to other areas. Masks & ventilation help lower 🥅 #COVID19 risk.🧵
publichealth.yale.edu/research_pract…

2) To measure how poor ventilation affects transmission risk of #SARSCoV2 while skating in indoor ice arenas, infection probability was modeled for various scenarios. looked at the impact of: HVAC supply air flow, the number of COVID-19-infected people on the ice, and mask use.

3) Ice rinks are often shared by 50 people on the ice. At 7% test positivity rate, 4 COVID-19 infected people could be skating at a given time. In both high- & low-HVAC ventilation, the probability of infection increased 2.4-3.5 times for one infected skater versus 5 on the ice.

4) The importance of wearing a mask is reinforced with these estimates – the probability of infection was found to be 1.5 to 2.5 greater for people not wearing a cloth mask compared to skaters assumed to be wearing a mask.

5) “Also, elevated levels of combustion-derived pollutants in indoor ice arenas can possibly increase the risk of COVID-19 infection, while temperature (55-65°F) & humidity (33-47%) levels designed to preserve integrity of the ice surface may also stabilize SARS-CoV-2 aerosols.

6) “Conclusions.

Poor air quality, movement and mixing of the air can lead to elevated airborne contaminants at breathing height of skaters

Temperature and humidity conditions inside ice arenas are within range of conditions that may increase survival of #SARSCoV2 in aerosol;

7) “Co-exposure to elevated levels of air pollutants, such as fine particulates and nitrogen dioxide, may worsen severity of COVID

Highly aerobic activity like skating will enhance respiration, increasing release of infectious aerosol if COVID-19 infected individuals are on ice

8) “Highly aerobic activity will also enhance the risk of transmitting SARS-CoV-2 through increased breathing in of airborne contaminants.

It’s reasonable to suspect that the use of indoor ice arenas will increase the exposure of skaters to SARS-CoV-2 aerosols.

9) “Athletic activities inside ice arenas may pose an increased risk of COVID-19 transmission compared to athletic activities in other indoor and outdoor environments.”