Archive for July, 2013

Listen up!

31/07/2013

traffic bicycleSshhh! Cycling’s way down the list of noise polluters. A well-maintained bike on a smooth surface can be near-silent (assuming the rider isn’t wearing chain mail, playing a bugle or both). The peacefulness is one of its pleasures.

So that makes a bicycle a relatively good platform for collecting other sounds on the move. What you do with those noises is up to you and different scientists are doing surprising things.

There’s a team in Austria that’s been eavesdropping on a rider as she pedals around the town of Graz. She knew about it. Before she started she phoned the lab and kept the call connected. The researchers were able to hear all the sounds around her wherever she cycled.

Then they analysed the audible clues and, like sound detectives with their ears to the ground, they succeeded in working out her route just from the noises they heard through her phone. It’s an impressive result.

It’s not clear from this experiment who had the most fun but it does show that even if you doubt the existance of Big Brother (he does exist), it seems that he doesn’t need to watch you to find out where you are. All he has to do is listen and he’s got you located.

The research paper will download when you click here.

Elsewhere, three unfamous (as yet) Belgians have been cycling round cities capturing the traffic noise as they ride. At the same time they’ve been sampling the air, not just through their own mouths and noses but also through chemical sensors.

They made 200 trips and then calculated that there is a relationship between traffic noise and the level of carbon particles that pollute the air. This shouldn’t be very surprising because it stands to reason that the more traffic there is, the noiser it is and the greater the quantity of pollutants they are pumping into the atmosphere.

Here’s the clever thing about the research. Lots of people want to know how dirty the air is in our city streets at different times of day and in different weather conditions. The general aim is to keep the air cleaner somehow or other and thus improve everybody’s health. The problem, though, is that air quality monitoring equipment isn’t cheap.

By showing that noise levels are a reliable indicator of air pollution levels, the Belgian team says that audio recordings captured by street-level microphones can reveal the truth just as effectvely as air quality sensors. And microphones are much, much cheaper.

How ironic that the toxic emissions from motor vehicles will be more easily monitored because of an experiment by cyclists.

The abstract of the research can be seen here.

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