About 15,000 tonnes of material enter the Earth's atmosphere each year from meteors. I know the makeup of satellites vs. random meteors isn't exactly the same, but it's probably not concerning in terms of pollution sources, and it's really hard for me to imagine it getting there.

When you consider the century-long global effort burning 2-3 billion gallons of oil every day to raise CO2 from 320ppm to 420ppm, you get a sense of the scale involved.

Yea ~0.033% to 0.040% took ~879,000,000,000,000 kg of carbon with the oceans sucking up another 590 Gt, and land taking 528 Gt from 1750 to 2012. We added another 0.004% in the last 10 years.

Just wait until you learn just how much random space stuff enters Earth’s atmosphere in any 24 hour period

Someone already mentioned burning oil, I'd like to also mention coal which makes oil look very clean by comparison. Coal is a few ppm uranium, arsenic, and other unpleasant metals (this is from memory, but it has lot of impurities). We burned literally billions of tons of it, putting thousands or tons of these metals into the atmosphere in the process.

Also, leaded gasoline

this argument is pretty general; you're a priori attempting to prove that "acknowledged insignificant things are actually significant". This feels too strong!