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Breathing easier could be as simple as crossing the street

By

October 7, 2009

Researchers have found that traffic pollution levels change dramatically within small geog...

Researchers have found that traffic pollution levels change dramatically within small geographical areas (Photo: BabyDinosaur via Flickr)

Low emission vehicles, such as the Toyota Prius, promise to dramatically cut levels of noxious fumes on city streets. But, until such vehicles start to dominate the roads, people still have to cope with what spews forth from the tailpipes of their fossil fuel-powered cousins. However, researchers have recently found that pedestrians may be able to reduce the amount of traffic pollution they breathe in simply by crossing the street.

The research, led by Professor of Environmental Modelling Alison Tomlin from the University of Leeds' Faculty of Engineering, has shown that air pollution levels change dramatically within small geographical areas - dependent on wind patterns, the location of traffic queues and the position and shapes of the surrounding buildings.

The findings showed that pollution hotspots tend to accumulate on the leeward side of the street (the sheltered side), in relation to the wind's direction at roof-top level. They also revealed that that carbon monoxide levels were up to four times lower in parallel side streets, compared to the main road.

The team monitored traffic flow and carbon monoxide (CO) levels over an eight week period at one of the busiest junctions in the UK - the intersection between Marylebone Road and Gloucester Place in West London.

"CO levels were highly variable over remarkably short distances," says Professor Tomlin. "As you'd expect, the junction itself showed high levels caused by queuing traffic but, with some wind patterns, these hotspots moved further down the street. However, the leeward side of the street had consistently higher concentrations of carbon monoxide than the windward side. The same trends would be expected for other traffic related pollutants such as ultra-fine particles and nitrogen dioxide."

"Most people would expect pollution levels to be slightly lower away from the main body of traffic, but our figures show a very significant difference," she says.

The research found that pollution could be trapped within the street it is emitted by recirculating winds, but if it escapes above roof-top level it doesn’t tend to be mixed back into neighboring streets very strongly. This suggests that cyclists and pedestrians could massively reduce their pollution exposure by moving just one street away from the main thoroughfares.

The research team says their research has significance for local authorities and other bodies monitoring air quality in urban areas.

"Monitoring stations tend to be sited in what are expected to be pollution hotspots, but our research has shown that hotspots move depending on meteorological conditions, particularly wind direction," says Professor Tomlin. "We need to develop models which take these factors into account, so that the data from monitoring sites can be accurately analyzed to provide a true reflection of air quality across the whole of an urban area."

The research appears in the journal Atmospheric Environment.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag.   All articles by Darren Quick
6 Comments

cross to other side this block, hug wall.. reverse sides at next intersection....

complex solution to a simple to fix problem. No I.C.E. no fumes.

Remember, these guys got paid to tell us this. And any regular pedestrian already knew. Downwind, bad :upwind, good. any camper learns this at the first campfire. and the advantages of a windbreak...use your nose, it knows

Anybody can't fill in a few details of elaboration.....needs a guide to go out anyway.

waltinseattle
8th October, 2009 @ 11:39 am PDT

While this is a nice bit of common sense, we all are ignoring the 363.63kg gorilla in the room, scooters. Scooters produce more smog than a Hummer! http://economicefficiency.blogspot.com/2008/08/scooter-polluter.html In larger, lesser developed countries, scooters are more common than cars and create significantly more pollution.

Too bad major scooter manufacturers haven't found a way to reduce emissions.

gormanwvzb
8th October, 2009 @ 01:43 pm PDT

Scooters are better served by electric power. They are for short trips (no weekend trips to Granma's house) and can be recharged nightly.

A large surcharge on ICE scooters, and a rebate for electric scooters could sway the buying public to go electric.

But until battery technology prices come way down (EEStor? Quantum Battery?), then for most people the initial capital outlay for a more expensive electric scooter will be prohibitive, even if lifetime total operational costs are lower...that's were the rebate comes in.

matthew.rings
8th October, 2009 @ 11:18 pm PDT

Hmmmm Gorman - sweeping cliches about scooter pollution - really make one look a bit prone to being generally under half baked, on account of a great deal of countries having been mandating the introduction of high efficiency 2 and 4 stroke engines in scooters.

The days of the smokey over lubricated 2 stroke are long gone.... and going even faster.

Scooter manufacturers HAVE found a multitude of ways to improve efficiency, and reduce emissions - down to very very low levels....

Thus the uninformed, unresearched, unqualified and ignorant statements - well they are fine, if your the kind of person who lives and thinks like that.

Mr Stiffy
9th October, 2009 @ 12:17 am PDT

Vehicles running on electricity are the best option for this generation which is suffering with global warming.

mikencube
9th October, 2009 @ 03:36 am PDT

That blog condemning scooters is very suspect. I find it difficult to place much stock in someone who claims to be authoritative yet who remains an unidentified blog author. Gorman's post may also be nothing more than a plug for a blog that gets its author money for each ad view.

Gadgeteer
9th October, 2009 @ 05:46 pm PDT
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