[MeganM (OP)]

John wants to know:

With the growth in the use of cubesats and other low earth orbit satellites, what will the impact be, in terms of atmospheric pollution, when the thousands of various devices return to thee Earth's atmosphere and burn up?

What do you think will happen?

[Origin]

What do you think will happen?

I think they will enter the atmosphere and burn up.  There is no problem, unless a large satellite doesn't burn up all the way and hits somebody.  We are constantly bombarded by natural space junk.

From the NASA site (https://solarsystem.nasa.gov/asteroids-comets-and-meteors/meteors-and-meteorites/in-depth/)

When meteoroids enter Earth’s atmosphere, or that of another planet, like Mars, at high speed and burn up, they’re called meteors. This is also when we refer to them as “shooting stars.” Sometimes meteors can even appear brighter than Venus -- that’s when we call them “fireballs.” Scientists estimate that about 48.5 tons (44,000 kilograms) of meteoritic material falls on Earth each day.

[marcus1RM]

Yep, I think they will burn up.

[syhprum]

astronomers will breath a sigh of relief!

[Johnrhx1]

I am the original poster. Thanks everyone for your interest. I would like to clarify my question. My thought was not so much as will they burn up but what happens to the material from which they are made. These cubesats are and will be made of unique and rare metals and chemicals. When the satellite burns these materials will not be destroyed as such. Therefore they will fall to the earth and enter the foodchain through water supplies, fish and other foods such as meat and vegetables.

[evan_au]

The 1-2kg of dust from an evaporated cubesat will be spread fairly thinly over a large area.
It will be pretty negligible compared to the 40 tons of meteoric dust which is also spread fairly thinly over the whole Earth, every day.

The main contamination concerns are about radioisotopes which could find their way into the foodchain and be incorporated into our bodies.
- Radioactive thermal generators tend to be designed to survive reentry - but to have a controlled reentry over a deep ocean.
- Cubesats generally use solar power + batteries, and lack the thrusters needed for a controlled reentry into a specific target area.
See: https://en.wikipedia.org/wiki/CubeSat