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Black Soot On My Car!

June 28, 2015

By Paul Homewood  





There has been some discussion of soot and its impact on Arctic ice recently, so I thought I’d throw this in.


I bought a white car a couple of months ago, my first for donkeys years. With it being white, it is really noticeable just how much black stuff is left on it every time it rains, particularly light rain.

I took the picture above today, after some light rain overnight, having washed the car on Friday. The black smudges have not been picked up while driving, but have been left behind as the raindrops dried up.

Having had dark coloured cars previously for many years, these black specks have been much less noticeable in the past.


What they are and where they have come from, I have no idea. But, as we don’t live next door to a smokestack, it would appear they are pretty widespread.

  1. June 28, 2015 5:36 pm

    It may not be relevant to this (due to the time of year) but, here in London, in winter, I can smell very clearly that salvaged wood is being burnt at night. There is a distinct smell which, I assume, comes from fire retardants, paint and preservatives and which must be a hazard beyond whatever soot is thrown into the atmosphere.

  2. Joe Public permalink
    June 28, 2015 5:51 pm

    I’ve got the ‘opposite’ problem – my car has a black roof. Within 24 hours of washing it, there’s always a thin layer of either light-coloured dust, and/or pollen on it.

    Whilst the Greenies will probably say you’re suffering from soot from evil fossil fuels, I expect them to sympathise that I’m suffering from the joys of nature.

    BTW – metallic bronze might not be everyone’s aesthetic preference of car colour, but it camouflages the dust deposits pretty well.

    • June 28, 2015 6:32 pm

      My dad had a metallic bronze Singer Vogue back in the 60’s – lovely colour.

    • AndyG55 permalink
      June 28, 2015 10:06 pm

      Hint.. If you never wash the car, eventually you can’t see if there is a new layer of dust. ! 🙂

  3. Graeme No.3 permalink
    June 28, 2015 6:37 pm

    I wonder if this affects solar panels?

  4. Mark Leskovar permalink
    June 28, 2015 6:39 pm

    Black Soot On My Car! by Paul Homewood: “…What they are and where they have come from, I have no idea. ”

    If you live by an airport or under air traffic patterns it could be burned jet fuel residual. If you live by heavy transportation/car traffic it could be what is commonly called “brake dust”. Or it could be just normal dirt and dust from your environment that you never noticed on your previous cars.

    • catweazle666 permalink
      June 28, 2015 9:43 pm

      “If you live by heavy transportation/car traffic it could be what is commonly called “brake dust”.”

      Or tyre dust.

      It would be interesting to know the quantity of that – and its chemical analysis – that is deposited on the roads and into the atmosphere on a yearly basis.

      A very significant amount, I suspect.

      • RockySpears permalink
        June 29, 2015 6:30 am

        Tyre tread wears away. Hmmm where does the tread go? I never even thought to ask.
        Nor about brake linings
        nor about pollen
        nor about ….

        What else wears away, and by how much?

        We might have hit on the next big thing in Greenness

        (although particulates from diesel are up there already)

  5. George Meredith permalink
    June 28, 2015 7:05 pm

    Why ever would you want to wash a car? That’s just asking for trouble.

    • Joe Public permalink
      June 28, 2015 8:09 pm

      As Quentin Crisp might have said … “After the first year, the dust doesn’t get any deeper”

  6. tempestnut permalink
    June 28, 2015 8:07 pm

    Paul this study by the impeccably credentialed UNITED NATIONS ECONOMIC COOMMISSION FOR EUROPE shows that whilst we have reduced particulates from diesel engines significantly and in new cars and trucks to an effective zero, airborne particulates remain at similar if not the same levels as before. More evidence if it is needed that our regulators are often too one dimensional when seeking to clean the air up.

    Click to access Diesel_Engines_Exhausts_Myths_and_Realities_2014.pdf

  7. June 28, 2015 9:04 pm

    A lot of it will be Saharan dust scooped up and blown North. We had a lot of red stuff in Cornwall a few weeks ago from this source. The black stuff might be particulates picked up and blown off the roads when it is dry. This will mostly be a mixture of rubber and tarmac. If ever you had a lot, it would be interesting to brush some up and get it analysed.

    • July 1, 2015 9:24 pm

      Red Saharan dust from the plume, fell in a shower last night.

  8. June 28, 2015 10:51 pm

    Can CO2 be reduced via uv insolation in the stratosphere? What happens to the carbon atom? Does this also involve the production or reduction of O3? Can the extreme UV use the stratospheric snowflakes and CO2 to produce a carbohydrate (1-C6H12O6 + 6-O2)? What keeps the H2 and O2 in the atmosphere?

  9. tom0mason permalink
    June 28, 2015 11:36 pm

    It looks like you have found some real carbon pollution.

    • AndyG55 permalink
      June 29, 2015 2:39 am

      I live 100m from a major black coal line, (Newcastle NSW)

      Oddly, the dust I get on my white car (the one I do wash occasionally), is usually brown.

  10. June 29, 2015 1:43 am

    Paul that’s what the salesman meant when he said high spec

  11. Timo Soren permalink
    June 29, 2015 2:52 am

    Actually it could be care fine dust that accumulated while driving etc… but very fine and when it rains the water consolidates these together to form these flecks. If you take a cotton tipped sticks and grab some of these a quick inspection will reveal if they are single entities or a conglomorate.

  12. J Greenwood permalink
    June 29, 2015 4:05 am

    Have you ever wondered where the rubber that rubs off tires goes? I think That’s what you are seeing. Most prevelant in urban areas. I see a government program here. Why a movement to capture it hasn’t emerged is anyone’s guess. Perhaps if we can come up with a way to make money off it we can start a protest movement and get rich. I failed to see the possibilities that Ozone depletion presented and got in on the global warming boom way too late.

  13. Ben Vorlich permalink
    June 29, 2015 6:38 am

    Diesel buses and lorries and brake dust would be my guess if you live in or close to a large town.

    Have a go at removing what ever is in your roof guttering and you’ll find a lot of black dust in with leaves, moss, bird droppings and other detritus. I used to be amazed when I lived in the East Midlands just how much black came down in the rain.

    • June 29, 2015 8:20 am

      The East Midlands, that would be “The Black Country” of old.

  14. June 29, 2015 9:12 am

    #1 Recycling centre “accidental” fires … might be one FREQUENT source
    #2 Residue from the Electric Car recharging centre at (AKA Drax woodchip burning power station) ..might be another.
    … parking your car near Scunthorpe steelworks used to also have the same effect.. It might be better these days ..and anyway’s probably moving to India soon.

  15. Tony B permalink
    June 29, 2015 11:53 am

    Years ago in our town, there were very vocal calls to the local power station about coal soot causing black spots on laundry, cars, etc. It went on for quite some time. As part of a science research project, one of the students at a nearby high school did some study and analysis. Turns out the source was a dry cleaning store. Go figure.

  16. fredericmora permalink
    June 29, 2015 3:00 pm

    Looks like diesel soot. That’s a side effect of having a lot of small diesel engines running on short distances in automobiles.

    • tempestnut permalink
      June 29, 2015 10:52 pm

      Fredericmora, unlikely to diesel engine soot, more likely to be rubber from tyres. Black smoke from older diesel engines disperses and does not form lumps big enough to precipitate out of the atmosphere and be visible with the naked eye, despite most people beliefs about diesel engines.

      • AndyG55 permalink
        June 29, 2015 11:51 pm

        Got stuck behind an old diesel car yesterday spewing so much black smoke you couldn’t read the numberplate because of the soot, could barely breathe until they turned off.

        Needless to say, It had a “Greens” sticker on it.

      • tempestnut permalink
        July 1, 2015 8:38 pm

        Andy at least you are still alive to tell us that. If that had been a similarly poorly maintained petrol engine the carbon monoxide would likely have made you very sick or killed you. And because carbon monoxide is colourless and odourless you have no idea you are breathing it in until the instant you pass out, which is often too late to be revived. CO (produced in prodigious amounts in petrol engines and miniscule amount in diesels) was the first gas to be regulated from petrol engines, back in the days when our regulators were regulating against real poisons and pollutants.

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