About this Piece
When Dan Visconti approached me about composing a work for the Verge Ensemble, I knew that I wanted to construct a musical map. At first, we tossed around the idea of mapping the super-storm Hurricane Sandy, but I decided to focus a more positive event. In order to acknowledge that the United States Congress was once proactive and responsible for good environmental policy, I wanted to create a piece that would tell the success story of the Clean Air Act, which was voted into law 50 years ago.
This piece is a musical map. It renders into sound the declining densities of six different air pollutants between 1980 (when the EPA began to measure these pollutants) and 2010. Each pollutant is represented by a different instrument in the ensemble: Carbon monoxide (CO) by the flute, Ground-level ozone (O3) by the violin, Sulfur dioxide (SO2) by the clarinet, Nitrogen dioxide (NO2) by the cello, Lead (Pb) by the vibraphone, and two different sizes of Particulate Matter (PM 2.5 and 10) by the marimba.
Every year, each of the six pollutants is recorded as a mean (in parts per billion, or PPB) or in micrograms per cubic meter. Each yearly mean is represented as a reciting tone in the melodies of the piece, played on weaker beats or partials of the beat. Each pollutant also has a standard deviation (up to the 90th above the mean and down to the 10th percentile below the mean). These deviations are represented by the range of pitches that wander above and below the reciting-tone mean for each year.