How pedestrians can reduce intake of traffic pollution

Washington, October 06 (ANI): A new research suggests that pedestrians walking in a heavy traffic zone can avoid the pollution by simply moving a little away.

Professor of Environmental Modelling Alison Tomlin from Leeds' Faculty of Engineering who led the research claims that air pollution levels change dramatically within small geographical areas due to many factors.

Apparently, wind patterns, the location of traffic queues and the position and shapes of the surrounding buildings determine the level of pollution.

Traffic flow and carbon monoxide levels were watched over an eight week period at the intersection between Marylebone Road and Gloucester Place in West London to come to the conclusion.

It was observed that pollution hotspots generally tend to accumulate on the leeward side of the street, in relation to the wind's direction at roof-top level.

The researchers also found that carbon monoxide levels were up to four times lower in parallel side streets compared to the main road.

Tomlin said: "CO levels were highly variable over remarkably short distances. 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 ultrafine 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," the expert says.

"Pollution can be trapped within the street where it is emitted by recirculating winds. If it escapes to above roof-top level, it doesn't tend to be mixed back into neighbouring streets very strongly.

" It would be worth cyclists and pedestrians rethinking their regular routes, as they can massively reduce their pollution exposure by moving just one street away from the main traffic thoroughfares," the researcher added.

Tomlin believes that authorities monitoring pollution levels in urban areas need to look at other factors identified by the research to ensure an accurate spatial picture.

Tomlin said: "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.

"We need to develop models which take these factors into account, so that the data from monitoring sites can be accurately analysed to provide a true reflection of air quality across the whole of an urban area." (ANI)