Comments by "David Elliott" (@davidelliott5843) on "How Dangerous are Jet Contrails u0026 Rocket Exhaust ?" video.

  1. The big problem with today’s car diesels is the microscopic dirt particles. Back in the 1980s diesels we’re visibly smoky until authorities cut the allowable mass of soot. Car makers chopped the total mass but did nothing about the microscopic pm10 and pm2.5 which do the most biological damage. Strangely the visibly sooty exhausts are the least harmful because the lungs can remove big particles and being big they quickly drop out of the air.
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