Weatherwatch: how cycling can measure local air pollution

Get on your bike: cycling can be a useful way to measure local variations in weather and also pollution, using portable and inexpensive weather monitors attached to handlebars.

The researcher John Cassano made rides near Boulder, Colorado, using a compact weather station attached to his bike. Cycling in winter for half a mile revealed local temperature changes of more than 10C (18F), a larger contrast over small distances that surprised Cassano, and a sign of how significant microclimates can be created by the landscape, such as small dips in the ground or nearby fields, woods and built-up areas.

Another survey by Jordi Mazón in Spain used a bike to measure air pollution from CO₂. He took rides across Barcelona and the nearby city of Viladecans and found levels of CO₂ shot up by about 90ppm over only a few hundred metres, largely from traffic, but dropped sharply near a forest, urban parks, and agricultural land – a sure sign of the part that trees and vegetation can play in reducing urban pollution.

Bikes used as weather stations have the advantage of being well ventilated, sampling over short times and distances, and highlighting very local effects such as built-up areas and nearby trees.

Researchers hope lots of cyclists using this equipment riding through urban areas can highlight all sorts of very localised weather and pollution, in the future hoping to divert bicycle users from heavily polluted areas or accident hotspots where poor weather increases the risks from traffic.