Skip to content

Bristol Temple Way Emissions

April 28, 2020

By Paul Homewood


Following my look at air pollutants in Sheffield the other day, Adrian Kerton has now done the same with his local Bristol site. Particularly relevant as Bristol City Council are at the forefront of plans to ban diesel vehicles from the centre of the city.

Worth a read.


  1. Phillip Bratby permalink
    April 28, 2020 11:10 am

    If you didn’t know the dates, you would have no idea which was before and which was after lockdown. Presumably the weather conditions were very similar for most periods. Most emissions blow in from elsewhere.

    • Phillip Bratby permalink
      April 28, 2020 11:11 am

      “most” = “both”.

    • April 28, 2020 11:24 am

      Thanks I’ve updated to show lockdown was declared on the evening of the 23rd March. Perhaps the wind caused by the traffic moving previously dispersed the emissions, either way, if I am right their case for an exclusion zone seems unproven.

      P.S. If you know anyone in the NHS please direct them to the website where they can download short stories that might give them a smile.

  2. Jonathan Tucker permalink
    April 28, 2020 11:35 am

    So where does it come from? The probable answer is from normal domestic activity of gas and oil heating, not the wicked motor trans port. In France where we have an interest we have occasion to travel to nearby Grenoble. The motorway around the city is often subject to speed restriction for vehicles because of “pollution”. When I say we have 2 French neighbours each of whom burns over 40 cubic metres of wood a year (no misprint) is it any wonder that there is pollution but the demon car gets the blame!

    • Michael permalink
      April 28, 2020 1:56 pm

      40 stère? Wow, usually €50 a pop. Sounds like he needs some insulation fitting, would pay for itself very quickly. The last 7 years we’ve used ~10 stère/yr, we’ve just finished the main refurb and have only used 5 this winter. It’s a lots less work too.

    • Mike Jackson permalink
      April 28, 2020 2:00 pm

      That is some serious wood-burning, Jonathan! We use around two stères (cu m) a year for one log burner, roughly from November to about now. Perhaps they live in a chateau?

      I seem to remember that Grenoble introduced a system of licensing for diesel cars a few years ago to combat their pollution problem. They have a problem of geography which in certain weather conditions means the air quality can be eye-watering. Literally!

      Add to that the traffic from the ski resorts on Saturdays during the season can be horrendous. I’ve seen tailbacks up the Romanche valley from Pont de Claix to beyond Vizille!

      There really is no point in our trying to hide from the fact that our personal transport is polluting, just nothing like as bad as it used to be. At the same time we are healthy, wealthier, and longer-lived than we have ever been so we don’t seem to be suffering. Our ecomanic friends could do with developing a sense of proportion! I live in (not much) hope!

    • A man of no rank permalink
      April 28, 2020 5:31 pm

      This is interesting. Paul’s blogs keep noticing that NO2 levels on our streets are not dropping when fewer cars are about. It appears that we have to find other sources of this polluting gas.
      It cannot be from atmospheric Nitrogen, N2, which is unreactive.(This is the source of NO2 via the internal combustion engine.)
      A quick read finds that wood contains a tiny amount of Nitrogen – about 1 atom for every 500 atoms of carbon. In this form Nitrogen will be far more reactive than in the N2 molecule. As wood burns in air it would be easy for Nitrogen to produce NO2 – in very small amounts. In fact the University of Winchester warn about the asthmatic effects of wood burning stove:

      Click to access 2017_Wood%20burning%20stoves%20Layman-1.pdf

      This lockdown is very interesting!

  3. richardw permalink
    April 28, 2020 11:48 am

    I can’t post the chart here, but I’ve looked at the rolling 12 month average (to eliminate seasonal variations) background pollution in London. In just over a (fossil-fuelled) decade from December 08 – August 19, levels dropped as follows:
    NO2: -31% (now 29% below WHO guidelines)
    PM10: -18% (now 8% above WHO guidelines)
    PM2,5: -29% (now 29% above WHO guidelines)
    This is remarkable progress. It will be interesting to see the figures for the lockdown period.

  4. john cooknell permalink
    April 28, 2020 11:54 am

    Fist thing to check would be the sensors, then how the results get interpreted into a published reading.

    The sensors and interpretation would likely have been set up to indicate “traffic pollution”.

    If you remember the 2010 icelandic volcano spewed dust everywhere according to the authorities, all air traffic was banned across Europe! I kept looking up at clear blue sky and wondered! It took 8 days for the authorities to believe their eyes and realise there was nothing there or more correctly so little dust it did not matter, nothing really out of the normal.

  5. David Virgo permalink
    April 28, 2020 11:57 am

    There is a clear daily spike in these data which is notably low on Sunday and high on Saturday both before and after lock down. The weekday spike appears to be substantially lower after lock down than before. It is the spikes that are most likely to be toxic.

    • Phoenix44 permalink
      April 29, 2020 9:57 am

      But that’s then nonsense. If spikes are “toxic” you have to show that the “excess deaths” were exposed to the spikes. But that doesn’t work. You can’t link enough people to that.

      And of course the spikes are still 25% of the levels in 1970 when we weren’t all dying from air pollution.

      All the “deaths” are statistical, with extremely low effects (only just above one) but because you apply them across tens of millions of people you get what seems like a big number you should act on.

  6. ianprsy permalink
    April 28, 2020 12:04 pm

    All a bit academic? All Bristol has to do is follow TfL.

    Just heard Young Mr Bamford of JCB fame giving Talkradio’s host the hard sell on hydrogen buses, including such gems as they’ll get their electrolysis energy from a wind farm in Kent and yes, you can use saline water as the electrolyte, just desalinate first.

    The article below mentions the aimed-for price of an electric bus at £350K v/v a conventional one at £230K. Current price is £1m.

    I wonder what creative accounting TfL have had to do to justify their proposed contract.

    • ianprsy permalink
      April 28, 2020 12:11 pm

      Correction – £m until recently, now a cool £350K.

    • Gerry, England permalink
      April 28, 2020 12:24 pm

      TfL was in financial trouble before the lockdown with falling tube income, Crossrail delays and Saddo’s policies. 80% of staff are furloughed but TfL are paying the missing 20%.

  7. April 28, 2020 12:37 pm

    These are some of the highest values after lockdown but appear to be when there would be very little traffic. 4th April is a Saturday. Weird?

    2020-03-31T07:00:00 101.94
    2020-04-01T09:00:00 145.73
    2020-04-04T00:00:00 115.71
    2020-04-04T02:00:00 103.85
    2020-04-04T03:00:00 138.47
    2020-04-04T05:00:00 112.84

  8. MrGrimNasty permalink
    April 28, 2020 3:08 pm

    It’s long been obvious that private motor cars are a minor player in general city air quality (which is why they lump them in with all traffic and don’t talk about Gas Central Heating), the demonizing is purely a political agenda.

    Yes there may be temporary localized hotspots at kerbside, but people only pass through and as soon as you’re a few yards away you’re clear. This is less ‘bad’ for you than standing by a gas hotplate, or a BBQ, or near a tandoori/char-grill restaurant etc.

    The London Mayor and the usual suspects did another press release a few days ago, saying how the air had improved – London and Leeds were particularly mentioned and curiously only NOx (as if that were the only measure). I checked and there was a pretty convincing reduction in NOx on for example London Marylebone Road ‘kerbside’, but not other pollutants. Then it gets curious, look closer, the sudden drop first started on 18th March, then a peak on 23rd, then another sustained drop.

    I checked the past weather and it becomes remarkably clear – there has been a corresponding run of N/E winds. March, late 4th and into 5th wind shifts NE – pollution drops 500 to neg. 19th shifts NE pollution drops again, stays N/E until 23rd when turns SE and pollution spikes again, 26th veers NE again pollution drops – and extraordinarily the wind has maintained that direction (with low pollution) until part of 25-27th April with a small spike, veered NE again on 27th April.

    Is the variation just when the wind blows air to or away from the sensor!

    And back to the middle of Brighton (not kerbside) – absolutely no evidence of a decrease in pollution correlating to the shutdown.

    ‘They’ cannot even reliably blame the private motor car if there is a genuine reduction. Bus journeys have gone to almost zero, cabs too I expect, construction plant and HGV traffic must have fallen off a cliff. The weather/season has changed substantially in the period resulting in massive GCH use variation. But most obviously our air quality is determined mostly by the source of our air, every time it comes from Europe (esp. the Ruhr and surrounding areas) pollution goes up.

    There’s lots of codes to plug in for the defra graphs here (says if kerbside).

    And you can find local past weather at timeanddate dot com, if anyone wants to investigate locally to themselves.

    • April 28, 2020 6:37 pm

      Thanks for the link to the air quality site, I’ll update my blog with some graphs tomorrow. The large spike corresponds to a marked change in wind direction but then the correlation falls apart. I’ll need to look further.

      • MrGrimNasty permalink
        April 28, 2020 8:52 pm

        Looking longer term:-

        There is perhaps a suggestion of a slight decline in all NOs with the shutdown, but it’s not so inconsistent with previous levels that you’d look at the data and suspect something had changed.

        Also Feb data missing – broken sensor, site move?

        It’s a very inconsistent picture countrywide – there is certainly no clear dramatic improvement which is the narrative eco-alarmists/MSM are trying to create.

    • Phoenix44 permalink
      April 29, 2020 10:01 am

      We really should put up a legal challenge to Sadiq’s Low Emisdion Zone using this data. It us not only wrong, it penalises the poor disproportionately for not being able to buy a new car. It is obvious from the dara that cars and in particular diesels are a major contributor to PMs.

      • Phoenix44 permalink
        April 29, 2020 10:01 am

        Oops, terrible typing. NOT a major contributor to PMs.

  9. MrGrimNasty permalink
    April 28, 2020 3:09 pm

    Paul, another Magnum opus in moderation to kick out, cheers!

  10. sonofametman permalink
    April 29, 2020 9:03 am

    The city air is no longer being filtered and cleaned up by passing through internal combustion engines……..

    • MrGrimNasty permalink
      April 29, 2020 9:53 am

      I remember a Saab advert, they claimed the exhaust was cleaner than the air going in!

      1993 “Proved by government scientists, no less, when they conducted tests in the City of London last autumn. Thanks to its unique Trionic engine management system, exhaust emissions from a Saab 9000CS 2.3 litre Turbo were found to have lower levels of both hydrocarbons and nitrogen oxides than were found in the surrounding air.”

      I think someone also made the same claim for a Porsche 911 Turbo driven in LA!

  11. jack broughton permalink
    April 29, 2020 2:08 pm

    Fascinating info (as always on this site). It is interesting to see how much of the ground level pollutant levels are actually natural in origin. At coastal locations PM10 and PM2.5 are largely salt……being near the sea is the clue here. NOx levels are also interesting as they also correlate with ozone levels, ozone reacts with nitrogen to produce NO and NO2.
    We may be close to the natural background levels of these “deadly pollutants”, in which case the massacre of the car industry will have been to no avail.

    I live in the centre of England and my car has been coated in sand twice recently: we have no beaches within 100 miles! Isn’t the weather / climate amazing.

Comments are closed.

%d bloggers like this: