Air Carrier Captain reported an unresponsive passenger prior to gate pushback caused by an elevated cabin temperature and APU exhaust entering the aircraft. The passenger revived and was deplaned.

Narrative

At the gate and about 10 minutes prior to scheduled departure from Gate XX in ZZZ and with the main cabin door open; a passenger in seat XXX became unresponsive to the Flight Attendants' (FA) commands during her pre-departure cabin passenger count walk through. The Flight Attendant reported that the passenger appeared to have momentarily passed out; as he was not responding to her taps on his shoulder or to her verbal communication. The Flight Attendant advised me of the situation and so I advised the First Officer (FO) to contact Operations on the radio and request paramedics be called to the gate. The gate agent also called 911. I called my dispatcher and advised her of the situation. The Duty Manager was also notified. The Flight Attendant made a PA to request the assistance of a trained medical professional; if any were present onboard. There was an EMT that was traveling on the flight and who was able to assist the unresponsive passenger; who a short while later on work up and was able to respond and correctly answer basic questions. The EMT advised that his vital signs were also normal; but that the passenger was showing signs of dehydration and so he was given some water by mouth. The passenger's wife; mentioned that he had been drinking [alcohol] all day while playing golf the day prior. The airport paramedics arrived after about 5 minutes who assessed the passenger's medical condition. After about 5 minutes the paramedics removed the passenger from the aircraft. A wheelchair was offered; but the passenger was able to walk off the aircraft on his own accord. The aircraft Emergency Medical Kit (EMK) was not utilized; nor were the EMK seals broken during the onboard medical incident. The ill passenger and the passenger's wife did not re-board the flight and which departed 19 minutes later than scheduled. A contributing factor may have been the elevated cabin temperature in the rear of the cabin during boarding. There were very high Southerly winds (gusting 40 kts) blowing directly from behind the aircraft. The packs were not used during boarding because of the likelihood of additional APU exhaust fumes entering the aircraft cabin. Prior to the incident I could smell APU exhaust fumes on the flight deck resulting from outside air entering through the open main cabin door. Furthermore; the ground PC air was unable to be utilized due to the strong winds. As a suggestion; that Company Operations in ZZZ give consideration to utilizing Gate YY; instead of Gate XX; during operations in high winds blowing from the South; when ground PC air operation is possible as a result; so as to permit the normal operation of aircraft packs/APU without the risk of APU exhaust ingestion in the aircraft cabin - due to a less than ideal aircraft orientation in relation to the wind velocity