smoking pic

We all know that smoking is bad, but even if you don’t use cigarettes, you’ve been exposed to secondhand smoke. Just how much may surprise you.

A new app, called Shit, I Smoke!, will tell you exactly how much passive smoking you’re doing while walking down crowded city streets. After seeing the numbers, you might decide that moving to the mountains and becoming a recluse is a good idea.

Designers Marcelo Coehlo and Amaury Martiny developed Shit, I Smoke! in a week. The app is free through both Google Play and the app store, so there’s no reason not to check it out.

There’s a fair bit of science involved in how the app works. The core is a mathematical model involving PM2.5. This is a tiny particle that becomes cancerous after combustion. Scientists have linked smoking tobacco-related deaths to certain levels of PM2.5

This article, Air Pollution and Cigarette Equivalence, breaks it down if you’re really into math and science:

“Here is the rule of thumb: one cigarette per day is the rough equivalent of a PM2.5 level of 22 μg/m3.”

Using that formula, and connecting with data pollution stations in major cities all over the planet (which update in real-time), the app is able to quickly (and presumably accurately) tell you how much secondhand smoke you’re breathing as you walk around town.

The beauty of the app is that takes a set of complex data and makes it easily understandable.

“These air-quality monitoring stations are just numbers, numbers that are very specific to professionals who work in environmental issues. So when you make this conversion to cigarettes, it makes it easier to understand what people are dealing with and the consequences air quality has in their daily lives,” Martiny explains.

The app currently only provides data for the city the user is in, but the team is planning to expand this to include other cities, monthly averages, and other enhancements.