I've seen those issues on our local rail trail too - one reason I haven't spent much time on it this year.
A Michigan journalist asked four infectious disease experts to rate 36 activities for Covid risk on a scale of 1 to 10. The doctors said the factors they considered were:
- Inside vs. Outside
- Proximity to Others
- Exposure Time
- Likelihood of Compliance
- Personal Risk Level. The Article
The ratings are based on expert opinion because there is minimal science; the numbers are an average of the 4 experts' ratings out of 10.
Interestingly, for dental offices, the one retired expert was out of synch with the others, rating it as a high risk situation and boosting the risk rating. Without going into detail, it is false that a trip to the dentist is riskier than a trip to the grocery store. The risk *might* be higher for the dentist but the jury is still out on that.
The risk factor that caught my eye was one that I've been thinking about a lot: Likelihood of Compliance. A different expert rated an outdoor wedding with 10+ guests as a high risk activity, which surprised me. Their rationale was that weddings are events where people are less likely to comply with social distancing, regardless of good intentions. Similarly, bars are rated as more risky than restaurants of similar design, simply because people are inclined to drink too much, get close and lose inhibitions.
Lack of compliance happens in little, unintentional ways too. On the weekend, I went for a "10 minute driveway visit" that extended to 25 minutes in the back yard simply because we're all starved for connection. As a one-off, that's not too risky but if I did that regularly, the additional risk would add up. It's really hard to set limits and comply with them because it's all so unnatural. I find it easier to avoid situations where it will be tempting to stretch my rules. Recently, a friend used considerable peer pressure including words like "stupid" in an unsuccessful attempt to get company for a run. There's an extra level of social stress arising from differences in personal and/or community-minded risk tolerance that's going to continue for a long time. Hence my search for science to help guide decision making.
The good news for people on Attackpoint is that everything points to the risk of outdoor transmission being much lower than indoor. One Japanese study found the risk outdoors to be 19 times lower. A Chinese study of contact tracing found only one outbreak traced to the outdoors (a conversation in the street) out of hundreds of cases. Compared to being indoors, there's more air flow and more dilution of virus particles. If it's sunny, the UV makes it even safer. Double the distance to 4 meters, add masks if you want to be extra careful, ask your friends if they have symptoms before they come over, set a time limit, don't breathe hard or sing together, don't do it too often, and you have an option for low risk social interactions until the science becomes more clear.