I know this is more wildland related, but interesting subject
the Apple fire that started in Cherry Valley and caused the evacuations that displaced thousands before it raced into the ridges and canyons of the San Bernardino National Forest was caused by burning carbon from the exhaust system of a diesel-fueled vehicle.
So first time I heard about this, in all the years of wildland fires.
Examples of particles on page 217::
[
www.nwcg.gov]
NFPA 921 does have one short paragraph on DPF.
So does this also apply to some locomotives??