Mephitic Air

The fourth in a series of installations on air pollution and its data, Mephitic Air examines the moment-to-moment function of sensors used to analyse the air, and what they may add to our own senses of the world around us.The data being visualised and sonified here is being produced live by air quality sensors mounted on the roof of the gallery. These sensors measure wind speed, wind direction, and the quantities of three common pollutants: Nitrogen Dioxide (NO2), Carbon Monoxide (CO) and particulate matter smaller than 2.5 micrometers (PM2.5).

The three screens in the centre of the room show live visualisations of this data. Each visualisation gets larger and denser as the amount of air pollution measured by the sensors rises, and each pollutant is represented using forms and colours relevant to their materiality. NO2 is represented as a bronze liquid-like visualisation, which is its state at room temperature; CO as a gaseous white; and PM2.5 as metallic particles. Wind direction being recorded by the sensor’s weather vane determines the movements of each visualisation, while high windspeed makes the visualisations disperse, as high windspeed can dissipate air pollutants around sensors. The visualisation in the window uses the same colour coding but shows the total density of each pollutant measured over the day so far, revealing the rhythmic peaks and troughs of data collected by these sensors.

The sonifications read this same live data, with a sound representing each pollutant being measured. These sounds move through the room with the current wind direction, rising and falling in volume as each pollutant increases and decreases. Echo is applied as windspeed increases, dissipating each sound. The sounds used to sonify the data each reference a component of how air pollution functions. NO2 data is sonified with the sound of a car’s catalytic convertor, a component installed to reduce the engine’s emissions of NO2. These devices have the side effect of reducing engine efficiency while emitting PM10 and PM2.5 emissions as platinum residue from the lining of the convertor. In reference to this, the PM2.5 data is sonified with the sound of platinum mining in Norilsk, Russia, one of the most polluted industrial mining towns in the world. CO data is sonified with the English traditional song ‘The Cutty Wren’. The origin and intent of this song is debated; it may be as old as 14th century, and it’s argued to be one of the first documented English protest songs (with one interpretation of its lyrics being the killing and eating of the King to feed the poor). We include this here to highlight the ongoing role of creative practice as an ethical engagement with the conditions of the world.

Mephitic Air was conceived of and created by Wesley Goatley and Tobias Revell for Brighton Digital Festival at ONCA. Produced with the support of Arts Council England and Brighton Bus Company.