Junipers and cypresses are known for collecting pollutants from things like cars as they go by. It makes the air by you a bit better to breathe, but....
The flip side of that coin is that both have a downside. If you get pricked, scratched, etc. by them. The reason is, they are extremely dirty, because of what they collect. We found that any pricks/scratches from them also tended to swell, turn red and irritate, or even infect.
So, the best thing to do is wash your arms after trimming them, or whatever gets your arms in them.
Mind you, they are probably dirtier in someplace like the city than at your house.
We're both blessed with multiple types of oaks. I love the variety.
Love All Life, Thank You For Posting! :)