2. Data Domain and Design Principles for Air Pollution Sonification
Climate and weather data have been a popular resource for sonification research in the past, possessing time-varying and dynamic characteristics, which arguably afford temporal patterns for the ear to perceive. Previous explorations of climate data have often cited these as reasons for developing new sonification methods towards innovative scientific analysis (Schuett, Winton and Walker 2014). In more recent cases, such as Goudarzi’s user-centered approach (2015), the stated end-goal of the design methodology is to develop mapping strategies that serve the research needs of climate scientists. The data used is complex and multidimensional, requiring the sounding of many perceptually diverse mappings in parallel. Scientists were also required to learn the mappings over an extended period of time. In the case of a sonification of the solar system Quinton, McGregor and Benyon (2016) openly adopt an approach of a “pragmatic aesthetic” (Barrass 2012) towards the sonic representation of planets, aiming to create “mental images” that will aide in memory and retention. Their work, like our own, is framed as end-user sonification, and the evaluative method used actively questions parameter mapping sonification in relation to hearability (what they term the “human hearing” approach).
Sonic information designs such as these clearly open the issues of not only perceptual mappings but also aesthetic approaches to end-user sonification.If we consider the public sphere as the context of reception, the requirements are certainly different from those in traditional scientific sonification. Data presented in this context often needs to be simplified to drive home one or two highly important and impactful points. Fewer and different mapping strategies would be used, driven by pragmatic and evocative aesthetics to create sonifications with an engaging and reasonably familiar sonic character. The message behind the sonification needs to be self-evident, not requiring specialized ear training to perceive. Spectral bands utilized in the sonification would be clearly delineated in order to ensure discernibility in busy, crowded ambiences full of competing auditory information.
For this project, air quality was chosen among the broad spectrum of climate data based on its availability, social relevance, and its recurring presence in the media’s continuous coverage of issues surrounding climate change. Because of this coverage, the public is arguably more primed to understand the connections between air pollution, health impacts, and the contributions of harmful emissions to climate change. A sonification of air quality data, then, serves as an access point to further understand the gravity of the situation. It is this underlying principle that guides our design. Sonifications for four Canadian cities: Vancouver, Edmonton, Toronto, and Sarnia during the year of 2014 were generated from available data retrieved from provincial websites for British Columbia, Alberta, and Ontario respectively. Within each dataset, five metrics of air pollution were identified and sonified. These elements are ozone (O3), particulate matter (PM2.5), nitrogen dioxide (NO2), carbon monoxide (CO), and sulphur dioxide (SO2). The choices made and the process of sonification itself were geared towards an audience of everyday listeners, aiming for hearability, intelligibility and engagement with socially relevant data.