On Tuesday 10 April 2012, the monitoring site on Neasden Lane became the first location in London to breach the National Air Quality Strategy (NAQS) Objective for PM10 for the year. The NAQS objective allows a daily mean PM10 concentration of 50 ug m-3 on not more than 35 days per year. Provisional measurements indicate that PM10 on Neasden Lane has been above this threshold for 36 days during 2012.

The Neasden Lane monitoring site is located close to a number of regulated waste and other industries that add to the PM10 concentrations in the area. Neasden Lane itself is a residential street with many houses and flats located close to the road.

Previous studies conducted around Neasden Lane Goods Yard have demonstrated that particles from local industry affect the surrounding area. Evidence from work around other waste management sites in London and work done by researchers in the US suggest that elevated PM10 concentrations may extend up to 1 km along haulage routes from these types of facilities, although concentrations at 1 km will be very much less than those close to the monitoring site. The pollution measured at the Neasden Lane monitoring site does not reflect pollution over Brent or London as a whole, but it is very important with respect to exposure of local residents. Over recent years, PM10 concentrations have improved at the Neasden Lane monitoring site; the 50 ug m-3 threshold was exceeded on 167 days in 2006 and this decreased to 77 days in 2011.

Details of the Brent 5 monitoring site on Neasden Lane can be found on London Air.

Note: Although the UK NAQS objective for PM10 reflects the EU Limit Value there are differences in the way that they are assessed. Assessment of whether city or region breaches the EU Limit Value is made in the UK by DEFRA using air pollution measurements in combination with modelling. Other factors including particles from natural sources, such as sea salt particles are also included in the EU Limit Value assessment.

Item date 11/04/2012