Turnpike Lane, Wightman Rd, and Green Lanes are above the EU legal limits for Nitrogen Dioxide ... if you're walking or cycling through Harringay its safer to use the Harringay Passage.
BBC London News ran a story about the study today which is up on iplayer.
But then, why at the top of Allison ?
NO2 is heavier than air, which makes me glad I live on the third floor
And another thing.
It ticks me off when I see diesel cars that are blatantly belching out black smoke. Not only is something very wrong with that vehicle (something that can be fixed) but it is just plain wrong! You and I, being the pedestrian or person in the chain of vehicles behind, are breathing that crap in, while the emitter just jollies on uncaring as his/her air is no doubt nice and clean.
So, I saw a car yesterday that frankly was creating a smoke screen and could I find somewhere to report it? I thought there was somewhere to report smoky cars, but this is the best I can find:
I saw several reporting points in various towns and cities around the UK, but nothing for London. Go figure.
I think for the same reason if this makes sense, busses powering up engines to pull away from the bus stops, and given the climb on Wightman as you go from (I guess) around Effingham to the where the road flattens out around Hewitt again you will see vehicles powering up to make the climb.
In both cases we are primarily talking about diesel powered vehicles as the catalytic convertor in a petrol powered car should (if at temperature) reduce NOx emissions pretty much to zero. I am sure you have been behind a diesel vehicle before and seen it bother out smoke as it either accelerates or the foot goes down as the engine is put under strain, especially if the vehicle is in too high a gear.
You may also have compounding effects of the bridge at Umfrevrille, and diesel powered trains using the train lines (?).
As to NO2 being heavier than air, there is so much mixing of air at this level John that being on the third floor will not save you, there is too much atmospheric turbulence.
Anyway, it is not directly the NO2 that is the issue. I forget how bad it is for you, but it is the other secondary and tertiary pollutants that NO2 go on to produce such as Per-oxy Acetyl Nitrate (PAN), etc, that in hot summer conditions are produced by the swamp of pollutants being hit by high energy UV light (PAN is the lachrymatory substance that will make folks eyes water, and bring on various asthmatic type illnesses etc.
Where NO2 is important probably as an indicator for other pollutants that will have a more direct negative impact on your health John, such as particulate matter (soot to you and I). Busses and cars pump out stuff called PM100, and PM50 (ie, particulate matter below 100microns or 50microns in size). The PM50 especially is the nasty stuff as it gets through a lot of face masks and is especially insidious as it is going to get into your lungs that much more easily (and give rise to the next big generational cancer epidemic, lung cancer in non-smokers (this last bit is my own opinion)). The risk of lung disease is very real though, we are all breathing this crap in and filtering it out with our lungs!
Much of this is linked directly to diesel vehicles, as the use of catalytic convertors in cars has had a massive impact on air pollution in the last generation. From memory, the reason we have not seen the same improvements in diesel vehicles is because the unburnt carbon (soot) tends to coat the catalyst and thereby stopping it from oxidising any unburnt hydrocarbon (diesel) and reducing any NOx back to normal N2. This is why the VW Defeat softwear thing is so massive. Because of the 'improvement' in engine performance demanded of engine manufacturers/car retailers we would have expected significant reductions in the main vehicle based air pollutants, but the reality is they have stayed static, and at worse increased in some cases. The fact that it has been so cynically undermined by the VW, and who knows who else is as stunning a revelation as the tobacco industry supressing data showing smoking will kill you, or a chemical company is knowingly polluting the groundwater we all drink (think Eron Brockovich)...
Isolating the 'culprits' as being mainly diesel vehicles certainly makes sense. It certainly doesn't seem that traffic volume on the rung roads is the principal or only cause. If you look at Seymour, which has barely any traffic, it registered pretty much the same level as Allison and Effingham, the two closet east-west rung roads, which both have significantly more traffic.
I wonder if much of the pollution drifts up from Green Lanes and/or down from Wightman?
Ant, was all testing done at the same time of day?
I think it was done simultaneously and continuously at all sites over a period of a month.
Yes, NO2 affects babies in prams much more than their parents. NO2 is poisonous, diesel cars are very poisonous. Please stop driving them.