Someone in the hotel room was smoking cigarettes
These days, most hotels are all non-smoking.
Some hotels do not allow you to smoke on the property unless you are inside of your own car, but my partner plus I stopped smoking cigarettes about 10 years ago, however our noses are still truly sensitive to the odor.
I can odor a cigarette from a hundred yards away. My partner plus I went to visit some friends plus both of us stayed in a hotel. Our room was on the third floor, however halfway through the first night, our partner plus I started to odor the rotten stench of cigarettes. I got up plus looked around the room, because the odor was so strong. I truthfully thought for sure someone was inside of our room. The odor was coming from the Heating, Ventilation plus A/C unit. My partner plus I could not figure out how the odor of cigarettes was coming from the Heating, Ventilation plus A/C unit; Every one of us turned off the system plus the odor disappeared. When both of us turned the cooling system back on, both of us odored the poor stench of cigarettes again. My partner finally opened up the curtains on the window plus the 2 of us realized that someone on the third floor was hanging out of the window with a cigarette. The odor from that cigarette was coming up to the third floor plus right into our room via the Heating, Ventilation plus A/C system. I thought about calling the front desk to complain about the person on the third floor, but I did not want to be that person. Instead, our partner plus I decided to sleep with the cooling system off the rest of the night.