PM10 concentrations at the Brent 5 monitoring site are amongst the greatest in London. The monitoring site is located on a residential section of Neasden Lane in north west London. During 2005 the site measured 180 days with mean PM10 above 50 µgm-3 TEOM*1.3. This is a substantial breach of the Air Quality Strategy (AQS) Objective / EU Limit Value of 35 days per year. The site also measured an annual mean PM10 concentration of 62 µgm-3 TEOM*1.3, exceeding the 40 µgm-3 TEOM*1.3 AQS Objective / EU Limit value.

To understand the reasons for this breach of the AQS objective the London Borough of Brent commissioned KCL to study the local sources of PM10 at the site.

It was found that a local non tail pipe source accounted for just over half of the of the PM10 measured at the site and absence of this source the site would very likely have achieved the AQS Objective / EU Limit Value during 2005. This local PM10 source dominated the measured PM10 concentrations at the site during working hours on weekdays and during Saturday mornings. It is likely that the local non tailpipe PM10 originates from vehicle activity both within Neasden Lane Goods Yard and on Neasden Lane through the resuspension of silt from the road surface or suspension of material from ‘dusty’ vehicles. We cannot rule out the likelihood of fugitive sources within the yard itself.

The findings of the report have wider implications for future assessments of air pollution issues around waste management sites which should include resuspension of silt from the road surface or suspension of material from dusty vehicles.

(Photo - J Barrett LB Brent)

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Item date 10/05/2007