Brian Foo, a musician from the US has created a piece of music that coincides with the air quality data in Beijing over the past three years.
He recorded the particle pollutants data for three years and matched every day's data with each beat of a song from the Rock band-Nine Inch Nails.
The higher the air pollution index is, the longer the beat lasts.
More musical instruments are involved if the air pollution index is high.
Brian says he wants his music to express people's mood during the smoggy days.
