5 ms·

That isn't refuting my statement. Road transport includes all vehicles on the road, and my statement is that trucks are by far the largest source of particulate

That isn't refuting my statement. Road transport includes all vehicles on the road, and my statement is that trucks are by far the largest source of particulate matter on the road. The standards on trucks (and buses) are exponentially worse than passenger vehicles -- justified by the notion that they're doing something more worthwhile -- and many horribly polluting older models are grandfathered in. The average age of a passenger car on the road is much, much newer than the average age of a transport truck. https://pubs.acs.org/doi/pdf/10.1021/acs.est.8b01914 https://pubs.acs.org/doi/pdf/10.1021/acs.est.8b01914 The crux of that is that particulate pollution had a low correlation with passenger car volume, and a high correlation with trucks. Indeed, they found low utilization trucking routes had worse pollution than the busiest highway in North America (which would have been much more pronounced if the latter didn't also have significant truck volume). Though it is worth noting that there are a number of worse sources of particulate pollution. Wood burning fires, for instance, or home gardening equipment with virtually no pollution control.

chrisseaton 8y ago
> The standards on trucks (and buses) are exponentially worse than passenger vehicles How can one group be 'exponentially worse' than just one other group? How can you see an exponential relationship between two data points? That doesn't make any sense. You'd need to be looking at a relationship between at least three data points to say it was exponential.
- egwynn 8y ago
  You’re not wrong, but colloquially it’s common for people to use “exponentially” to mean “a lot”. Just like it’s common for people to use “massive” to mean “big” (i.e. large spatial volume).
- MR4D 8y ago
  Exponentially is often used to mean "10 times more". So if one date point is 10 times higher than a second data point, than the wording would hold colloquially.
  - chrisseaton 8y ago
    Are you confusing with 'an order of magnitude'? Exponential is a rate of change, so you simply can't determine it on two data points. Order of magnitude is the relative change itself, so you can determine between two data points.
    - oarsinsync 8y ago
      You are literally correct, and literally could not be more wrong (and I'm deliberately using both the correct and colloquial - but depressingly also dictionary defined - definition of the word 'literally' there). Language evolves, and not always for the best.
      - deleted 8y ago
        [deleted]
    - MR4D 8y ago
      No, but I agree that OOM is the better word choice. That's the great thing about the English language - whatever it means today, it won't tomorrow! Also, to address the definition of "exponentially", I refer you to the second definition here [0]: -- "any positive constant raised to a power." [0] - https://www.dictionary.com/browse/exponentially https://www.dictionary.com/browse/exponentially
      - chrisseaton 8y ago
        That's not what that definition means in this content. Think about it - you can express any change from A to B as a positive constant raised to a power. So if that's what you think it means then you're saying any change from A to B is rising 'exponentially'.
        jimmydddd 8y ago
        Well......Actually....
- endorphone 8y ago
  It was just an idiom as this isn't a technical discussion. I think most readers could get the idea.
- imustbeevil 8y ago
  If I have 5 accidents and you have 25 accidents you've had exponentially more. You don't need 3 data points, x^2 is an exponent.
Brakenshire 8y ago
Why is truck regulation so substandard? To enter the metropolitan London area (600 sq miles), HGV’s have to meet stringent pollution standards for particulates and NOx or else they pay £120 a day. Under those circumstances they aren’t a dominant source of pollution. You’re definitely right that wood burning stoves and static plant are big sources, although location of emission is very important, someone using garden machinery intermittently on their own property or a wood burning stove out in the country is mostly polluting themselves, the same can’t be said for a freeway being driven through an urban neighbourhood.
- endorphone 8y ago
  Passenger cars in North America saw incredible advances in emissions almost entirely courtesy of California, that state spearheading demands to respond to the LA smog crisis that peaked in the 1980s. Other jurisdictions, like my home province of Ontario, just went along with the giant. It's why diesel cars are so rare, and as we know often lied (quite aside from the VW thing, every single instance where a diesel vehicle has been measured under actual use has seen emissions dramatically worse than claimed). Big trucks, however, couldn't make the transition as quickly, and for the necessary torque still rely upon diesel. And they've gotten away with much, much worse, though again California is taking the lead and in the next few years older trucks will be banned from the roads. Regarding the location of particulate sources, I've read that even in London, England, something like 75% of the particulate matter is from outside the city, blown in from farms and rural areas.
  - Brakenshire 8y ago
    I was just reading about pollution sources, and you’re right that 75% comes into London from outside, compared to only 20% of NOx. Although levels of PM are double the concentration along roads compared to the background, so there is a local as well as a regional effect.

chrisseaton 8y ago

> The standards on trucks (and buses) are exponentially worse than passenger vehicles How can one group be 'exponentially worse' than just one other group? How can you see an exponential relationship between two data points? That doesn't make any sense. You'd need to be looking at a relationship between at least three data points to say it was exponential.

egwynn 8y ago
You’re not wrong, but colloquially it’s common for people to use “exponentially” to mean “a lot”. Just like it’s common for people to use “massive” to mean “big” (i.e. large spatial volume).
MR4D 8y ago
Exponentially is often used to mean "10 times more". So if one date point is 10 times higher than a second data point, than the wording would hold colloquially.
- chrisseaton 8y ago
  Are you confusing with 'an order of magnitude'? Exponential is a rate of change, so you simply can't determine it on two data points. Order of magnitude is the relative change itself, so you can determine between two data points.
  - oarsinsync 8y ago
    You are literally correct, and literally could not be more wrong (and I'm deliberately using both the correct and colloquial - but depressingly also dictionary defined - definition of the word 'literally' there). Language evolves, and not always for the best.
    - deleted 8y ago
      [deleted]
  - MR4D 8y ago
    No, but I agree that OOM is the better word choice. That's the great thing about the English language - whatever it means today, it won't tomorrow! Also, to address the definition of "exponentially", I refer you to the second definition here [0]: -- "any positive constant raised to a power." [0] - https://www.dictionary.com/browse/exponentially https://www.dictionary.com/browse/exponentially
    - chrisseaton 8y ago
      That's not what that definition means in this content. Think about it - you can express any change from A to B as a positive constant raised to a power. So if that's what you think it means then you're saying any change from A to B is rising 'exponentially'.
      - jimmydddd 8y ago
        Well......Actually....
endorphone 8y ago
It was just an idiom as this isn't a technical discussion. I think most readers could get the idea.
imustbeevil 8y ago
If I have 5 accidents and you have 25 accidents you've had exponentially more. You don't need 3 data points, x^2 is an exponent.

Brakenshire 8y ago

Why is truck regulation so substandard? To enter the metropolitan London area (600 sq miles), HGV’s have to meet stringent pollution standards for particulates and NOx or else they pay £120 a day. Under those circumstances they aren’t a dominant source of pollution. You’re definitely right that wood burning stoves and static plant are big sources, although location of emission is very important, someone using garden machinery intermittently on their own property or a wood burning stove out in the country is mostly polluting themselves, the same can’t be said for a freeway being driven through an urban neighbourhood.

endorphone 8y ago
Passenger cars in North America saw incredible advances in emissions almost entirely courtesy of California, that state spearheading demands to respond to the LA smog crisis that peaked in the 1980s. Other jurisdictions, like my home province of Ontario, just went along with the giant. It's why diesel cars are so rare, and as we know often lied (quite aside from the VW thing, every single instance where a diesel vehicle has been measured under actual use has seen emissions dramatically worse than claimed). Big trucks, however, couldn't make the transition as quickly, and for the necessary torque still rely upon diesel. And they've gotten away with much, much worse, though again California is taking the lead and in the next few years older trucks will be banned from the roads. Regarding the location of particulate sources, I've read that even in London, England, something like 75% of the particulate matter is from outside the city, blown in from farms and rural areas.
- Brakenshire 8y ago
  I was just reading about pollution sources, and you’re right that 75% comes into London from outside, compared to only 20% of NOx. Although levels of PM are double the concentration along roads compared to the background, so there is a local as well as a regional effect.