As close to none as possible, really - you're diluting probably a ton of kerosene in five and a half quadrillion tons of atmosphere. Plus it's happening ~150km

As close to none as possible, really - you're diluting probably a ton of kerosene in five and a half quadrillion tons of atmosphere. Plus it's happening ~150km up, mostly outside the atmosphere, so it's got a long time to dilute before it gets to anyone.