Atlas V from last week's launch of X-37B showing soot plume from kerosene fueled booster engine. The plume is asymmetric because the Atlas V booster has two side by side nozzles. The soot emission index (EI) of kerosene rocket engines is 20 -40 grams of soot per kilogram of propellant. The soot EI of jet aircraft is 1000 times smaller. Does this soot add up and have a global effect?