How many satellites would it take burning up in the atmosphere to raise the aluminum content of the atmosphere by just 1 part per billion (not million)? Each sa

How many satellites would it take burning up in the atmosphere to raise the aluminum content of the atmosphere by just 1 part per billion (not million)? Each satellite is 300kg, it would take 57 MILLION satellites. The cost to do that at current prices would be $138 trillion. Airplane exhaust has a real measurable impact on the atmosphere, curious why people choose to target satellite debris instead of plane exhaust as their topic of environmental concern.