Interesting piece from the FT on the potential risks related to urban cycling — primarily as a commute method. They highlight both the obvious potential danger from accidents as well as ingestion of pollution. Using a 30 minute cycle as the model you are generally going to be more than fine in all but the worst cities. 
From a safety perspective there’s the clear always wear a helmet rule to start but also you have to recognize cities create a whole new level of potential chaos. In my experience using CitiBike, pedestrians pose the greatest risk. As I’ve seen consistently, walkers are the apex predator on the street. They simply do not give a F and will openly walk in bike lanes, jaywalk and generally move against the perceived direction of traffic. I’ve found that although there are a ton of cars and trucks people pose the greatest challenge. 

Where I currently live is rather outstanding environmentally by contrast to the dense urban centers of the world …