Dear Rabbi Simon
Can I wear a mask outside on Shabbos?
Thank you for your practical and contemporary question. If you are wearing a mask in accordance with widely-accepted public health recommendations, ie to inhibit the inhalation and spread of Coronavirus, there are grounds to allow doing so on Shabbos, even in the absence of an eruv. One may apply the logic of SA OH 301:37 (and MB 138) to this case. Ditto for nitrile (surgical) gloves.
Best wishes and “control the virus” to stay healthy
Rabbi Rashi Simon