Are fans allowed to smoke in the stands/arena? My husband and I are allergic to smoke so we can't go if people around us are allowed to smoke.
The last fight I attended was in 2007 and smoking was permitted. I just read a couple TripAdvisor reviews and it was still permitted as recently as 2017.
Back to the original question, yes there is smoking and there are no, “no smoking” areas, so the people in front, behind, or beside you could be smoking. Seats are concrete, bench. Your only option is sun or shade seating.
Not only is smoking allowed but when we went there were many smokers. I'm afraid you will have to cross it off your list.
It is outdoor, obviously. When we were there a few years ago, I don't remember a lot of smoking but smoking is allow. If it is absolutely critical to avoid any smoking, then you should probably avoid an outside activity including cafes. While it is becoming more common to prohibit inside smoking, outside is not.
In some "regions" (ie Basque Country) it's not allowed to smoke in bullfight arenas (plazas de toros).