When we moved into a new house we noticed the air ducts were spewing out strange particles. I called around to see if there is an agency that could test if it's

When we moved into a new house we noticed the air ducts were spewing out strange particles. I called around to see if there is an agency that could test if it's dangerous and the short answer was "we'd only test if we know what we're looking for". If you price this reasonably ($100 or less) and are able to test for a range of substances, I would buy your product in a heartbeat. Don't listen to the nay-sayers, launch a test kit with a list of things you're checking for and see how the market responds. You can try the home buyers / home owners / parents markets, as well as restaurants, hospitals, you name it.