Android/iOS: Smoking is one of the best-known ways to poison your lungs, but good old fashioned air pollution plays a role, too. An app called Shit, I Smoke! (free on iOS and Android) puts your local pollution in terms you can understand.
Graphic: Shit I Smoke / VisualHunt
The maths comes from a Berkeley Earth analysis that compared the amount of air pollution in China to the number of deaths that were likely hastened by pollution. The country's 1.6 million deaths were equivalent to what you would expect if the population smoked 2.4 cigarettes per day. To see how this varies worldwide, take a look at this real-time map of air quality across the globe.
It's a rough calculation, but the idea of a link between pollution and health is well established. According to the Berkeley Earth map, on average people in the US breathe the equivalent of 0.4 cigarettes per day. Beijing is four cigarettes on an average day but can reach 25 when conditions are particularly bad.
According to Shit I Smoke, those in the Sydney CBD are smoking 0.9 cigarettes today.
Download the app, which translates your location in space and time to a number of cigarettes, and despair.