New York AQI Synth
New York City's air quality played as music. Live AirNow readings and EPA data back to 2020 drive a synthesizer and a sky, borough by borough.
Ever seen a smoggy sky out of your window and felt like you could just smell the air quality? Well, I wondered if I could hear it instead. This website turns New York City’s air quality index (AQI) data into sound so that you can affront more than just your nose and eyes on those smoggy days.
Melody
The melody is determined by Ozone levels. Every hour, the reading picks a note. The higher the value, the higher the note. Ozone builds through the morning and peaks mid-afternoon, which is why most days have similar rises and falls in the tune.
Rhythm
The rhythm follows Nitrogen Dioxide (NO₂), which mostly comes from traffic. More NO₂ in a four-hour stretch means more beats in that bar. Morning rush is the busiest part of most days.
Dissonance
Particulate matter (PM2.5) controls how rough the piece sounds. It picks the scale, pushes the notes out of tune, and adds reverb. On a clean day the notes are in tune, in major. On the worst days the scale is chromatic and everything is about a semitone off.
Scale
The six scale steps match the EPA's six AQI categories: Major, Pentatonic, Dorian, Phrygian, Locrian, Chromatic. The chord progression underneath is fixed.
The sky
The sky is rendered from physical models of the atmosphere, with the sun calculated and rendered where it was over New York at that hour. One model handles daytime, another handles night. Golden and blue hours at dusk/dawn are added on top.
The air
Particulate matter is drawn over the sky as noise and visual aberrations. At low levels it just bends the view a little. At high levels it tints everything amber. At really high levels, it turns into plumes of smoke you can see the sun through.
Data
Live readings come from AirNow every hour. The archive is EPA monitoring data from 2020 onward, and it runs about 12 weeks behind. New York doesn't publish live NO₂, so live views use a typical NO₂ profile for the current month and weekday, built from the archive. Some boroughs don't monitor every pollutant. Where there's no reading, that borough uses the citywide value.