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.
Who determined that the air quality was unhealthy on those 4 days?
the EPA
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.
Air quality in Boston is generally very good: during the ten-year period two thousand four-twenty thirteen, there were only four days in which the air was unhealthy for the general public, according to the EPA.
Who determined that the air quality was unhealthy on those four days?