Return of the Fire Alarm

Whee. There's a windchill warning in the province today, and the fire alarm just went off again. (Thankfully, *before* I took my clothes off for a shower!) This time the light was lit on the second floor, so perhaps it's time for that sensor to be replaced? (That's what they had to do on the third floor in order to get the last set of alarms to shut up.) Of course, when I got there, the heavy smokers on the second floor had opened and closed their door, so there was a strong smell of cigarette smoke. So... was it the cold, or was it the cigarette smoke? More importantly, does this herald another period of frequent alarms? (Blech.)