I was woken up briefly twice tonight, once by my flatmates returning home and talking to each other and again by the heating pipes clanging as I live in a prewar and the steam boiler turns on at 5 every morning. I also imagine the train noise from the Metro North/other outside vehicle noise has an effect I'm not aware of.
If anyone has studies about optimizing sleep quality given these kinds of conditions, I would be very interested to read about it.