Can “Pollution Glue” Clean Up London’s Dirty Air?

By Rav Casley Gera

London is one of Europe’s dirtiest cities in terms of air quality. Despite the UK capital’s innovative congestion charging scheme, it remains extremely busy with vehicle traffic. A recent study by campaign group Clean Air in London found that 13 schools in the city are situated near roads that carry more than 100,000 cars a day. And, of course, that’s set to increase significantly while the city hosts the Summer Olympics and Paralympics next year. Already, London frequently breaches European Regulations on the level of pollutant particulates, or PM10, allowed in the air.

Now, London’s city government is taking an unusual step to try to reduce the flow of pollutants into the city’s air — coating the busiest roads with “pollution glue” designed to absorb dangerous chemicals out of the air and ‘glue’ them to the tarmac. Transport for London, the agency that runs London’s famous Underground and buses, but also manages its roads, is to trial the use of ‘dust suppressants’ in 15 locations across the city. A solution of calcium magnesium acetate is applied to the roads using a specially-built vehicle with a sprinkler system attached. Calcium magnesium acetate has the effect of attracting fine dust particles in the air and binding them to the road, where they can be picked up by car tires or washed away by rain.

The new scheme expands on trials carried out on two locations in Central London last year. TfL says the previous trials showed dust suppressants could reduce the levels of particulates in their air by 10% in severely polluted areas. The new phase mostly targets roads in industrial areas, but the technology is likely to be extended to areas where pollution comes largely from heavy traffic. “Dust has been a real problem in the area and although it’s early days, indications are that these measures together are having a beneficial effect,” said Susan Wise, a councillor in Lewisham, one of the London boroughs involved in last year’s trial.

But as is often the case with such slightly sci-fi responses to pollution, the ‘dust glue’ plan has been criticized by green groups, who see it as a poor substitute for more muscular action to clean up air quality in the capital. “Suppressants may achieve compliance in localised areas near monitoring stations and avoid further action from the European Commission, but they address the symptoms and not the causes of the problem,” Alan Andrews of environmental law group Client Earth said in August. A better response is London’s Low Emissions Zone, which requires drivers of high-polluting vehicles such as lorries to pay a daily fee to enter the capital. After several postponements, the LEZ is being extended to larger vans and minibuses in January.

Source: http://cleantechnica.com/2011/12/28/can-pollution-glue-clean-up-londons-dirty-air/