Hmm, thank you for your thoughtful comment again. However, this study compared S gene positive and negative PCR tests sampled within the same time frame. So, I think the pandemic circumstances - e.g., weather, risky behavior, viral inoculum dose - may be indirectly controlled this way?

But aerosolization is a good point. Maybe the emerging strains are better apt at surviving and travelling in aerosols. That would also explain their increased transmissibility and virulence.