Audience Details: according to a report, 40% of the American population is exposed to unhealthy air quality.

Benefits: It is likely that people living in polluted areas can extend their life expectancy by at least one year.

Costs: $100/year using a low-cost Smart Air purifier from a B Corp

Evidence: Multiple RTCs support the negative effect of PM2.5 on lifespan

Details: Given the low levels of awareness and relatively low cost of implementation, we have opted to use the default 5% difficulty score.