Stopping at red lights exposes drivers to high levels of air pollution, new study finds

February 12, 2015, University of Surrey
traffic jam

Research published today in the journal Atmospheric Environment has found that drivers are exposed to dangerously high levels of air pollutants when stopped at red lights.

UK commuters spend an average of about 1.5 hours a day at the wheel. Road vehicles in particular are known to emit polluting which contribute to respiratory and heart diseases. Now, researchers at the University of Surrey have found that where drivers spend just 2% of their journey time passing through traffic intersections managed by lights, this short duration contributes to about 25% of total exposure to these harmful particles.

The team monitored drivers' exposure to air pollutants at various points of a journey. Signalised traffic intersections were found to be high pollution hot-spots due to the frequent changes in driving conditions. With drivers decelerating and stopping at lights, then revving up to move quickly when lights go green, peak particle concentration was found to be 29 times higher than that during free flowing traffic conditions. As well as concentration, found that as cars tend to be close together at lights, the likelihood of exposure to vehicle emissions is also significantly increased.

"Air pollution was recently placed in the top ten health risks faced by human beings globally, with the World Health Organization linking air pollution to seven million premature deaths every year," said lead author, Dr Prashant Kumar, from the University of Surrey.

"Our time spent travelling in cars has remain fairly constant during the past decade despite the efforts to reduce it and with more cars than ever joining the roads, we are being exposed to increasing levels of as we undertake our daily commutes."

"It's not always possible to change your route to avoid these , but should be aware of the increased risks at busy lights. The best ways to limit your exposure is to keep vehicle windows shut, fans off and try to increase the distance between you and the car in front where possible. Pedestrians regularly crossing such routes should consider whether there might be other paths less dependent on traffic light crossings. Local transport agencies could also help by synchronising traffic signals to reduce waiting time and consider alternative traffic management systems such as flyovers."

Explore further: Virtual traffic lights as in-car systems go with the real road flow

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not rated yet Feb 12, 2015
Now they can go see how bad it is in traffic jams.....
not rated yet Feb 13, 2015
Yeah, riding a bike may be the green alternative but you still get to suck down all the car exhaust from the other people who don't see it that way.
Carbon monoxide causes brain damage in pretty small quantities, ever take a stroll next to a busy street? Welcome to the brain damaged future! Freaking humans....
5 / 5 (1) Feb 13, 2015
Not stopping at red lights is doubtless even less healthy.

Commuters could choose to shut their windows and outside vents and crank the AC. In turn increasing load on the engine, etc.

I'm waiting to see oxygen masks offered as an auto accessory. Probably first in China, since they have the worst air pollution problem along with a crazy bunch of entrepreneurs.
not rated yet Feb 13, 2015
Sounds like a good reason to ban cars, and the people who drive them.
5 / 5 (1) Feb 13, 2015
Uh, when did car ventilation systems lose the facility to switch between 'intake' and 'recycle' air ?

Or is it like the humble turn indicator, lost some-where in the 'space shuttle' complexity of too many cars' controls ?

{ We call this the 'Too Posh To Signal' effect, especially when combined with a SatNav's belated bleatings of 'Turn Left ! Turn Left !' }
not rated yet Feb 14, 2015
Electric/hydrogen cars are a solution. On a motorbike I pull in front of the polluters so less of a problem

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