Mounted diffusion tubes in Green Lane

One of the concerns about the proposed Tfl estate project by the underground station, in the centre of Northwood, is the effect on pollution levels in the centre of the town if the Tfl Proposal is built.

One main component of pollution is that arising, not surprisingly, from vehicle traffic.

The pollution experts monitor many aspects of this kind of pollution but two of the most prominent concerns have to do with the levels of Nitrogen Dioxide and the levels of various sizes of particulates in the air we all breathe.

In order to establish the existing levels of pollution Northwood’s Voice has arranged, with Hillingdon Council’s permission, for the monitoring of one aspect of this pollution – namely Nitrogen Dioxide.

Northwood’s Voice has been working with an environmental company used from time to time by Hillingdon Council and we have, at our own cost, sourced their equipment for our monitoring exercise.

Further, this environmental company analyses the findings and reports back to us.

Existing Situation:

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As everyone in Northwood is only too well aware, the introduction of a set of traffic lights in Green Lane a number of years ago, adjacent to the Tfl underground station has caused considerable traffic delays through Northwood – and almost certainly raised the traffic pollution levels in the air along Green Lane as a result.

Northwood’s Voice are not aware of any pollution studies having been carried out before and after these traffic lights were introduced. Similarly, a mini-roundabout was introduced in Green Lane – very near to the traffic lights and once again may well have raised traffic pollution levels in Green Lane and in the centre of our town.

To some extent the Tfl underground station is already an area of much concentration of vehicle traffic – the traffic light junction by the underground station is already used routinely by buses, taxis and commuter parking traffic using the Tfl car park at the bottom of Station Approach.

The future effect of Tfl proposals on pollution levels:

Whilst Northwood’s Voice has been able to measure Nitrogen Dioxide pollution this year, we can expect the levels to increase in the future – even if no further property developments are approved by Hillingdon Council.

Click on pluses below to read more on these points:

Extra set of traffic lights in Green Lane:

The sketches which Tfl have revealed to-date of their proposals to handle traffic arising from their property development project in the centre of our town are seemingly lacking in some detail, but people have been advised that another set of traffic lights will be introduced just 50 yards or so along Green Lane from the existing set of traffic lights outside the underground station.

This new set of traffic lights is seen as necessary in order to allow traffic to enter the new Tfl proposed estate down a much widened Central Way (currently a footpath between “Taylor Made” and “Lee Gardens” shops in Green Lane).

Northwood’s Voice understands that Central Way is owned by Hillingdon Council, not Tfl, and thus Hillingdon Council themselves will be very influential in approvals for this widening and thus the viability of the Tfl proposals.

Thus in a very short distance past the underground station, of maybe 100 yards or so, Green Lane will have two sets of traffic lights and a mini-roundabout to contend with.

A traffic situation that is already very difficult for Northwood residents is likely to become much worse – and of course there will be an effect on traffic pollution which is not likely to be favourable.

Click and collect traffic:

Tfl has been introducing a variety of schemes at numerous other underground stations around their network involving “click-and-collect” facilities.

The following statement has been taken from the Tfl website  “Our Click and Collect partnership with the retailers has been a tremendous success for all involved, and we are delighted to be expanding the service to more locations, making it easier for more customers to order their goods and conveniently collect them at their chosen station.” 

Tfl have (perhaps conveniently) not said yet whether they plan to roll out this “tremendous success” to Northwood and, if so, the level of additional traffic and traffic pollution that we might expect in Green Lane.

Property development:

Up to 500 additional people may be expected to live in the proposed 4/5 floor flat and housing development by the Tfl underground station.

There will thus be a large number of additional cars (and delivery vans) coming and going  – and once again the effect of this additional traffic on air traffic pollution in Green Lane is not likely to be favourable.

Future Building in Northwood:

As we speak there is yet more and more large scale property development (including many flats) taking place in Northwood and as these properties are not yet occupied we have not yet felt the effect that the future cars arising from all this current property development will have on future levels of traffic congestion and pollution along Green Lane as these people travel about.

For example, most Northwood residents will be familiar with the new (yet to be completed) “Pinnacle” development now standing on the site of the former Reindeer Public House.

This development has 12 flats and an equivalent number of parking spaces – right in the heart of our town, adjacent to Green Lane itself.

Further down Green Lane another new property development is currently underway at The School of Theology (“Bible College”) which also involves 12 flats and also with associated parking.

Just a little further away the long line of large new blocks of flats along Ducks Hill Road is presently being added to yet again.

The latest block, presently under construction, will have 10 flats and associated parking – and once again will further add to Northwood traffic congestion and traffic pollution.

There are numerous other examples but this portrays a reasonable picture of the sort of future traffic congestion and future traffic pollution that has been approved and has yet to hit us – even without any of the latest Tfl proposal for more than 100 flats and houses by the underground station.

Background reading:

For those people who are interested in reading more widely on this subject – you might have a look at the following links…………..

Nearly 200 councils breached NO2 limits in 2013, Please read this articlehttp://www.airqualitynews.com/2015/09/10/nearly-200-councils-breached-no2-limits-in-2013/

European Commission Air Quality Standards-  http://ec.europa.eu/environment/air/quality/standards.htm

Hillingdon sees highest increase in air pollution deaths – http://www.airqualitynews.com/2013/11/06/hillingdon-sees-highest-increase-in-air-pollution-deaths/

Supreme Court decision critical of UK government re pollution levels– https://www.supremecourt.uk/decided-cases/docs/UKSC_2012_0179_PressSummary.pdf

Court Orders UK to cut Nitrogen Dioxide Air Pollution – http://www.bbc.co.uk/news/science-environment-32512152


Northwood’s Voice Newsletter

Published 23 September 2018

TfL Planning Application For Northwood Town Centre Conservation Area



Residents may be aware that Northwoods Voice Ltd (NVL) last published on-line details of our NO2 pollution monitoring on our website on 10th April 2017. This work was prompted by the proposal in 2015 from Transport For London [TfL] to demolish their existing town centre buildings and to submit a planning application for 128 dwellings (mostly multi-storey). The Air Quality Report submitted by TfL at the time was based on 6 months results from 4 air sampling locations using Diffusion Tubes – two of which were in Station Approach (a cul-de-sac leading to the station car park, with no through traffic).

We would now like to update residents on the results of nearly 3 years of continuous air sampling since then. We have recorded NO2 pollution at two separate locations in Green Lane, Northwood itself – both locations still being within the Transport for London (TfL) estate and the Northwood Green Lane Conservation Area.

Since 2010 the yearly average maximum concentration standard set by the EU for Nitrogen Dioxide has been set at 40µg/m3.   Our monitoring findings are displayed on the graph (at the end of this article) and broadly our (unadjusted) averaged results since July 2015 show that our recorded levels of monthly Nitrogen Dioxide were at 38.06µg/m3 just below the EU limit of 40µg/m3 but that the yearly trend, on a calendar basis, has been steadily rising over this period. As you will see from the graph there are considerable periods where the NO2 pollution level rises in excess of 40µg/m3. After several years of monitoring, there is some seasonal pattern to the graph now emerging which suggests to us that 3 or 6 month monitoring, as possibly done by consultants, may not be adequate in this Green Lane situation as some such periods will likely be below or indeed considerably in excess of the 40µg/m3

For the calendar year 2016:   average (unadjusted) NO2 was 37.01µg/m3

For the calendar year 2017: average (unadjusted) NO2 showed a slight increase to 37.35µg/m3

For the first 8 months of 2018: average (unadjusted) NO2 showed another increase to 41.64µg/m3 which is markedly in excess of the EU limit of 40 ug/m3. We plan to continue our monitoring at least until the end of 2018 and maybe beyond as there is a view which says that residents might wish to know the effects on pollution of new building (eg: the TfL project, but not limited to TfL projects) in the area both during any construction period and after any construction period.

As we mentioned in our News Bulletin of 10th April 2017, modern science has recently been focusing not only on NO2 pollution but also on the risks of fine particulates as small as 2.5 microns (a unit of length equal to one millionth of a metre, used in many technological and scientific fields. A human hair is about 75 microns across depending on the person.   As science’s understanding of what actually gets inhaled into our lungs and it’s effect on the body improves. NVL regrets that it is not equipped to measure fine particle pollution due to the equipment costs involved. It would be useful for this to be measured for Green Lane, Northwood near the Underground station where TfL may likely attempt to locate blocks of housing units and car parking.

A public announcement in March 2018 by TfL’s partners outlined their increased intent now to build more than 150 new homes on the Northwood town centre site which can thus probably be expected further to challenge air pollution in the town centre area.

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


Northwoods Voice 23 September 2018


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