generate questions: Air quality in Boston is generally very good: during the ten-year period 2004–2013, there were only 4 days in which the air was unhealthy for the general public, according to the EPA.
How is the air quality in Boston? {sep_token} How many days between 2004 and 2013 was the air unhealthy? {sep_token} Who determined that the air quality was unhealthy on those 4 days? {sep_token}