3 ms·

> tyre and brake wear is a relatively minor contributor to urban air pollution Why do you say that? Would love to know more, but all the research I've read lis

> tyre and brake wear is a relatively minor contributor to urban air pollution Why do you say that? Would love to know more, but all the research I've read lists them as significant contributors, second only to resuspension, each now exceeding tailpipe emissions on both PM 10 and PM 2.5. https://www.sciencedirect.com/science/article/abs/pii/S135223101630187X?via%3Dihub https://www.sciencedirect.com/science/article/abs/pii/S13522... https://dot.ca.gov/-/media/dot-media/programs/research-innovation-system-information/documents/preliminary-investigations/brake-wear-emissions-pi-a11y.pdf https://dot.ca.gov/-/media/dot-media/programs/research-innov... As an aside, we'd probably agree that vehicle weight is the mediating factor across all of these sources, regardless of the ratios from one type to the other. Massive load hauling trucks are generating a disproportionate share of emissions of all types, this is not really about making sedans a little more efficient.

Reason077 7y ago
Claims that tyre/brake particles exceed exhaust emissions are inevitably referring to particulate mass, not particulate count. One large particle can weigh as much as millions of nanoparticles, but is far less dangerous. Exhaust nanoparticles (sub-PM2.5) are small enough to penetrate the respiratory system, diffuse to the blood stream, and cross the blood-brain barrier. Here in London, some of the most obviously polluted and stinking roads are those where the traffic barely moves at all - lots of slow moving or idling vehicles. There isn't a great deal of brake or tyre wear when vehicles are standing still!
- brownbat 7y ago
  > Claims that tyre/brake particles exceed exhaust emissions are inevitably referring to particulate mass, not particulate count Huh, all the studies I've read and linked are comparing like with like within particle size categories. Idling considerations are addressed in the modeling too. You seem fairly unshakable here, but the topic seems well researched and the results are pretty unambiguous to me.
  - Reason077 7y ago
    Categorising particles into PM2.5 and PM10 is far too narrow. This doesn't adequately account for, and perhaps doesn't even measure, nano-scale combustion products. The 2.5 in PM2.5 refers to micrometers (μm), not nanometers (nm). If you're only counting the largest particles, then yes, a lot of them are going to come from tyres. https://particleandfibretoxicology.biomedcentral.com/articles/10.1186/s12989-015-0107-3 https://particleandfibretoxicology.biomedcentral.com/article... https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6558960/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6558960/

Reason077 7y ago

Claims that tyre/brake particles exceed exhaust emissions are inevitably referring to particulate mass, not particulate count. One large particle can weigh as much as millions of nanoparticles, but is far less dangerous. Exhaust nanoparticles (sub-PM2.5) are small enough to penetrate the respiratory system, diffuse to the blood stream, and cross the blood-brain barrier. Here in London, some of the most obviously polluted and stinking roads are those where the traffic barely moves at all - lots of slow moving or idling vehicles. There isn't a great deal of brake or tyre wear when vehicles are standing still!

brownbat 7y ago
> Claims that tyre/brake particles exceed exhaust emissions are inevitably referring to particulate mass, not particulate count Huh, all the studies I've read and linked are comparing like with like within particle size categories. Idling considerations are addressed in the modeling too. You seem fairly unshakable here, but the topic seems well researched and the results are pretty unambiguous to me.
- Reason077 7y ago
  Categorising particles into PM2.5 and PM10 is far too narrow. This doesn't adequately account for, and perhaps doesn't even measure, nano-scale combustion products. The 2.5 in PM2.5 refers to micrometers (μm), not nanometers (nm). If you're only counting the largest particles, then yes, a lot of them are going to come from tyres. https://particleandfibretoxicology.biomedcentral.com/articles/10.1186/s12989-015-0107-3 https://particleandfibretoxicology.biomedcentral.com/article... https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6558960/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6558960/