Compressor intake

Outside air can be polluted with all sorts of (small) pollutions, which can negatively effect your compressor. So you have to use good filters. Don't know where you live, but take in account that during winter time the compressor inlet might freeze

As long as the air inlet is properly designed, ie, good filtration, proper air flow considerations, just about anything will do the job. The compressor doesn't know or care where the air comes from as long as it's clean , cool (relatively) and, in sufficient quantity. Many OEM , read that as "stock", compressor installations in small outbuildings fail to take into consideration proper air flow, both for proper operation and for cooling. If you need an excessively long inlet air tract it is common practice to add a blower (squirrel cage or such properly sized) to aid in the airflow.

Rod

This could be a great advantage for you to pipe the air in from outside. This will keep your hot air in the room (if heated) or cool (if cooled). As the others have stated, proper filtration should be considered. Winter temperatures should not affect the inlet air, but any bird screens or louvers should be monitored for ice or snow buildup which may cause restriction. For long inlet ductiong, you can oversize the piping. There are several filtration companies that can calculate sizes for proper airflow. I contact Universal Silencer or Dynamic Filtration for outdoor filters. You should try to go with 5-10 micron filters. Note that if you are in the cement, aluminum or mining industry special filtration may be needed. Should you require more info or flow calculations, do not hesitate to contact me.

Mark
Aerzen technical Dept.