I live directly south in the line of a north-south landing strip of a low-traffic airport. What should I know?
1: At large international airports there has been at least some research to suggest that there may be affects on your health (http://www.latimes.com/local/la-me-0529-lax-pollution-20140529-story.html) but I'm assuming this is quite a small general aviation airport. With the low traffic, small planes, and far distance away frorm the airport, you are probably not experiencing much as a direct result of exhaust.

2: There is an almost no chance that an aircraft would land on your property. If one did happen to land on your property the NTSB does provide some guidance for public saftey personel: https://www.ntsb.gov/tda/TDADocuments/SPC0402.pdf. 

This PDF is aimed at public safety personnel. If you want to be an active participant in this emergency, feel free to follow it and the rest of this post. If you don't want to get involved, please just stay at a safe distance away from the accident and report it to emergency services.

If you are going to try to help you probably want to receive training on first aid before anything happens. Once an accident occurs you can do several things. For the most part, you initially respond just as you would to any other emergency, first by securing the scene and making sure you are not in immediate danger and then calling emergency services. Be careful when approaching the plane, especially if anything is still moving (propeller spinning etc). There are also many dangerous substances that could be present at the site of a plane crash (listed in the NSTB PDF). No one on the ground needs to be injured unnecessarily after a plane crash.

Once everyone is out of the plane, get far away from it and wait for emergency services to arrive.


Administer first aid (if trained) to anyone who was injured
Call the NTSB at 1-844-373-9922 to report the accident (It is the pilots responsibility to report the accident)
Take photos and video of the crash and surrounding area so investigators have plenty of documentation to look through to determine the cause of the crash. This will also be useful for insurance purposes.
If you see anyone else around who may have witnessed the accident, try to get their name and contact information to emergency services or the NTSB so they can be contacted if needed in any investigation