Airflow and back pressure question/Gas dryer

[Rockers]

Is there a simple way of measuring the airflow at the end or middle of our exhaust pipe coming from our gas dryer? Same for back pressure how do I measure that.
We have to install some sort of carbon filter at the end of the exhaust as our neighbors complaining about the smell , especially when we cure discharge inks. Unfortunately our location does not permit us to vent through the roof?
What other options do I have if I would like to run our exhaust pipe vertically. My fear is that we will end up with too many 90 degree bents which will restrict the airflow too much. There would be at least 3 of them before we can run the pipe vertically up wall between the two neighboring buildings. That pipe would need to be at least 45 feet long. So 3 x 90 a degreebend then 45 feet up, that surely will cause some back pressure to build up. right? Any options to prevent that?

[Binkspot]

Back pressure can be checked with a slack tube manometer. You can make one out of  2m of clear tubing, make it in the shape of a U with the two ends even. Fill with water half way. Poke a hole in the exhaust pipe and stick one end in the hole and secure with tape. Measure the distance between the water level in the tube. That will give you mm of water back pressure.
If you jump up a size in duct you should be fine with the distance. The three elbows will equal 15' of pipe. They make long radius elbows to reduce back pressure or you could possibly use some 30 degree sweeps.