ten raccoons @SaysEwe

I’m proud to have our latest research published on how long #SARSCoV2 remains infectious while airborne! We studied the fundamental processes that drive the loss of viral infectivity in the aerosol phase. #COVIDisAirborne Here’s a thread going over some of the findings.

@SaysEwe @sjta_amy @RpsAgainstTrump But christo-fascists at his level of information acquisition (i.e.: having an internet connection) must realize Russia is not really very Christian. And Putin is a religious fraud.

@ukhadds Al, this is truly incredible work 👏👏👏 It will significantly improve airborne risk profiling, modeling & mitigations for years to come Many thx for sharing your insights 😊😊😊

Indoor concentration of CO2 is highly influenced by the outdoor concentration, where the indoor CO2 concentration is usually higher. Thus, the increase outdoor ambient CO2 may have a much more significant effect on the indoor stability/transmission of the virus.

This study mechanistically connects the predicted rise in ambient levels of CO2 with an increased likelihood of respiratory disease transmission. As the global CO2 concentration continues to increase, the length of time respiratory viruses remain infectious in the air as well.

The expected increase in the concentration of CO2 in the atmosphere may also play a role in the emergence of new viruses. High CO2 concentrations will allow aerosolized viruses to remain infectious in the air longer, making it more likely to transmit from an animal to a person.

Using a Wells-Riley model, the time until there is a 50% chance that at least one susceptible person will become infected in a classroom containing a single infected person was estimated. Values are not absolute; rather, the trend of how CO2 conc affects the odds of transmission.

Increased concentrations of CO2 effected virus aerostability across a broad range of humidity. Below a humidity of 90%, the increase in CO2 roughly doubled the amount of virus that remained infective. This suggests that CO2 is more important than RH on aerosolized viral spread.

In terms of total aerosolized viral load, this means that after 40 minutes, more than 10x the amount of virus remains infectious in the air as a result of an increase in CO2 concentration. This will have a massive effect on the risk of transmission in a poorly ventilated space.

This data shows that the concentration of CO2 has a dramatic effect on how the aerosolized viral load will accumulate. Over longer periods of time at high CO2, the rate in which the virus becomes inactivated gets slower (after 20 mins only a subtle change in viral infectivity)

A moderate increase in the concentration of CO2 dramatically affected the decay dynamics. Changes in CO2 concentrations resulted in a completely different decay profile, where a difference in aerostability was observed within as little as 30 seconds, and throughout.

It has become popular to use CO2 monitors to estimate risk. This is based upon the idea that the CO2 informs about how well a space is ventilated. From our study, the results show that the levels of the CO2 will also inform about how long the virus remains infectious in the air.

Omicron was also found to be more aerostablethan the Delta variant across a broad range of humidities. Perhaps this played a role in Omicron rising to prominence?

Omicron (BA.2) was found to be more aerostablethan the Delta variant when the humidity was high. In our previous study, we found that as the virus evolved, it had lost aerostability. This is the first time we’ve recorded an increase.

When compared to the Delta variant, the Omicron variant is more stable in a highly alkaline solution (pH 11). This relationship further supports our hypothesis presented in our previous publications that the high pH of respiratory aerosol is driving the loss of viral infectivity.

We used a levitation/sampling technology we developed, called CELEBS (Controlled Electrodynamic Levitation and Extraction of Bioaerosols onto a Substrate), to probe the survival of different SARS-CoV-2 variants (Del+Omi) in mimics of exhaled particles in different conditions.

Implications: if the high pH of the respiratory aerosol is driving the loss of viral infectivity, it means that any increase in the conc of CO2 must have an effect of viral aerostability. The question becomes, will a difference be observable at CO2 conc in the real world?

Elevated CO2 concentrations in the atmosphere limit the degree the equilibrium goes right. Thus, excess CO2 will affect the maximum pH the aerosol reaches. The virus is sensitive to the pH in this region (>10); any subtle change in pH can have a large effect in aerostability.

When exhaled, the aerosol will reach a very high pH (>10) in 10s of seconds due to the dissolved CO2 (HCO3) leaving the droplet. The equilibrium shifts right, causing the acid (H3O) in the droplet to lower, resulting in a pH rise.

To help you better understand the background of the current paper, you may find it useful to learn about what got us to this point. I wrote a thread about it here: x.com/ukhadds/status…

Al Haddrell @ukhadds

10 months ago

I’m proud to have our latest research published on how long #SARSCoV2 remains infectious while airborne! We studied the fundamental processes that drive the loss of viral infectivity in the aerosol phase. #COVIDisAirborne Here’s a thread going over some of the findings.

109 1K 3K 490K 1K

Download Image