Making a Noise Pollution Monitor for International Environmental Journalism: Part 1. Design
Community noise is a common, yet often under-appreciated form of environmental pollution. European cities have stringent noise standards, and have been active in noise monitoring, modeling and control activities. However, in the United States, the federal Environmental Protection Agency has handed over noise issues to State and local agencies, which are often poorly equipped to deal with noise issues. Furthermore, developing cities around the world, where motorized traffic, construction, and population density are increasing rapidly may be homes to large populations who are exposed to noise pollution.
Photo: traffic in Beijing
What’s the big deal about noise?
Noise is more than just a nuisance. Instead, think of noise as an overall indicator of quality of life for people living in a city. Noise is often correlated with vehicle traffic levels, and especially truck traffic, which are also sources of air pollution. Yet traffic is only one source of noise. Car alarms and sirens heard at night might reflect the level of crime or safety that exists in a neighborhood. Conversely, the quietness of a neighborhood might reflect the calm of a peacefulness of a residential neighborhood. And the sounds of birds and rustling leaves in the wind might reflect the abundance of healthy green and relaxing areas in an area.
I have been working with Internews’ Earth Journalism Network (EJN) to design a noise monitor that fits the needs of environmental journalists, to facilitate story-telling of the sources and health impacts of noise from around the world.
Making something different from the status quo
Noise monitors aren’t a new technology. Numerous sound level monitors are available commercially for professional noise analyses. And in fact, many journalists already carry a type of noise monitor with them as they go about their work: a voice recorder. Also, increasingly, smartphone video recording has become the go-to tool for citizen journalists. Some smartphone apps allow users to make noise measurements.
Photo: a voice recorder
With EJN, we wanted to explore the design of a new noise monitor that:
- Would operate similar to a sound level meter, providing noise measurements in decibels (dB).
- Would not depend upon a journalist’s smartphone, so that if the journalist’s story demanded it, he or she could deploy multiple noise monitors in different locations potentially for long periods of time.
- Could benefit from the being connected to the Internet to store and share noise monitoring data.
- Would be based on an open source and do-it-yourself design, so that the design could be refined by the citizen science community over time, and monitors could be made at low cost with easily available parts sourced from well-known hobbiest electronics suppliers by anyone interested in noise issues.
Documenting our process
Through the next series of blog postings, we will describe our development process. Like all development processes, we started with an initial design. Figure 1 shows one of the first prototype designs based on an Arduino processor and a readily-available sound sensor ADMP401 breakout board from Sparkfun, and an electronic display sourced from Epictinker. This initial design was useful as a starting point for discussions with EJN, which included some of the following issues:
- Should we limit some of the features to keep cost low?
- How should data be displayed?
- Are the sound measurements calibrated to dB?
- How should the data be stored and analyzed?
- How should the monitor communicate with Internet services?
Figure 1. Initial prototype of the noise monitor
Next: Part 2. Prototyping – Sourcing Parts
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