Shit, I Smoke! was created by Brazilian-born designer Marcelo Coelho and Paris-born app developer Amaury Martiny in just a week, after they read a study that analyzed air pollution and its equivalent to cigarette smoking. The article--co-written by Richard Mueller, a MacArthur fellow and physics professor at the University of California, Berkeley--explains a mathematical model that compares smoking and tobacco-related deaths to levels of PM2.5, a microscopic particle that is a dangerous, cancerous pollutant after combustion.

Universal basic health care is also affordable. A country need not wait to be rich before it can have comprehensive, if rudimentary, treatment. Health care is a labour-intensive industry, and community health workers, paid relatively little compared with doctors and nurses, can make a big difference in poor countries. There is also already a lot of spending on health in poor countries, but it is often inefficient. In India and Nigeria, for example, more than 60% of health spending is through out-of-pocket payments. More services could be provided if that money--and the risk of falling ill--were pooled.

The evidence for the feasibility of universal health care goes beyond theories jotted on the back of prescription pads. It is supported by several pioneering examples. Chile and Costa Rica spend about an eighth of what America does per person on health and have similar life expectancies. Thailand spends $220 per person a year on health, and yet has outcomes nearly as good as in the OECD. Its rate of deaths related to pregnancy, for example, is just over half that of African-American mothers. Rwanda has introduced ultrabasic health insurance for more than 90% of its people; infant mortality has fallen from 120 per 1,000 live births in 2000 to under 30 last year.

And universal health care is practical. It is a way to prevent free-riders from passing on the costs of not being covered to others, for example by clogging up emergency rooms or by spreading contagious diseases. It does not have to mean big government. Private insurers and providers can still play an important role.

When The Economist writes sensible things twice in a row, is it time to start worrying?