Air Quality – Green Lane, Northwood 10 Apr 2017

Northwood’s Voice


Residents may have seen in a free publication that, Air Pollution Low In Northwood, figures show.

Unfortunately, no further details were given of the figures, how they were obtained and the location in Northwood. In view of the recent publicity on Air Quality toxicity alerts NVL considered residents would be interested in our work in this area and the reasons we are doing it.

Much recent air quality literature considers the influence of Nitrogen Dioxide and of particulates (both arising mainly from motor vehicle exhausts but not entirely) and the impact of these factors on public health. We, in Northwood s Voice, have since June 2015 been monitoring the monthly levels of Nitrogen Dioxide levels at two points along Green Lane, Northwood. This project was started in June 2015 because of the TfL development plans for Northwood Town Centre Conservation Area and is ongoing. We chose, with the awareness of the London Borough of Hillingdon Environmental Officers, the two Green Lane monitoring sites due to the TfL plans to erect multi-storey blocks fronting the B469 Green Lane. The scientific protocol we use is that which LBH itself uses including the analytical laboratory.

All our results were given to Hillingdon Environmental Officers at a meeting of the 23rd February 2017. They were pleased to have all our work as they have no Air Quality figures for Northwood in the North of the Borough.

Green Lane is a busy road where many people live, work and through which many commuters and school children pass almost every day. Our project is self-funded and thus we do not have the depth of resources to monitor fine particulates nor to measure hourly levels of Nitrogen Dioxide both requiring sophisticated equipment and which would add further to our knowledge of directly measured air quality in Green Lane.

Since 2010 the yearly average maximum concentration standard set by the EU for Nitrogen Dioxide is 40μg/m3. Our monitoring findings are displayed on the graph (end of article) and broadly our (unadjusted) results for the first year (July 2015 to July 2016) show that our recorded levels of monthly Nitrogen Dioxide were just below the EU limit of 40μg/m3 This level was of enough concern, however, to warrant an extension of our monitoring into a second year against a background of seemingly increasing traffic and traffic delays along Green Lane, something which most Northwood residents can probably recognise. We have already recorded a number of (unadjusted) individual monthly measurements in excess of 40μg/m3. It is possible that reported levels of Nitrogen Dioxide can be affected should weather conditions become adverse for prolonged periods.

In summary, and based on our observations, we would suggest that Air Quality along Green Lane, Northwood is at levels which require further and wider monitoring to more fully verify and understand the levels of Nitrogen Dioxide and possibly also fine particles to which some Northwood residents and children are exposed. As science develops a better understanding of the influence of fine particulates and Nitrogen Dioxide on public health then we may well see a lowering of existing air quality standards by the World Health Organisation.

Further explanation about Air Quality is given on our website under Pollution.

NVL. 10th April 2017




For those who would like to know more about Air Quality Management can we refer you to the following from defra.

1) Part IV of the Environment Act 1995

Environment (Northern Ireland) Order 2002 Part III

Local Air Quality Management

Technical Guidance (TG16)

April 2016

2) Local Air Quality Management Policy Guidance (PG16) 2016

Available at:

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