How does conversions to reduce air pollution

catalytic converter that turns dirty engine air into cleaner exhaust. it baisicly filters it.

Conservation is guarding, preserving and protecting. So conserving will help reduce air pollution because instead of letting thing go to the wrong garbage or whatever you can save and conserve and even reuse. decreases air pollution.

i think it's the first one because doctors aren't the ones who get rid of the old needles. most of them time it's not even doctors who give you shots, it's nurses.