Same here. I got a doctor's note and printed out a badge from asthma UK organization that clearly states I have breathing problems, medically exempt, Asthma, please be respectful. I wear it at work all day long, people are respectful. And I work with the public. They all comment on how sad it is that I have to wear a badge that states that so I don't end up on the evening news because people are so fucking nuts over masks.
Here ya go anon, print and laminate this. Cut out the UK part and put it on a lanyard and wear it like a boss.
Not where I work they don't. I breathe free all day long in a Blue state with governor mandates.