Received a phone call from them during the dinner hour, caller ID said "Environmental Sys" and he identified himself as calling from Environmental Services. He said they were surveying homes for air quality and started right in with questions as to whether anyone in my family suffered from asthma or breathing difficulties. I told him I don't know who he is, but I'm not up to answering personal questions or a sales pitch. He said "This isn't a sales pitch! We're just doing a survey." I said "no thanks, goodbye" and hung up. Upon doing research, I found that they DO sell air purifying and cleaning systems, and further research shows that the BBB revoked their Better Business Bureau accreditation due to failure to maintain the minimum rating. Their phone number is one digit off from that of Summit Air Industries which also has a D rating with the BBB, and whom has called here before and been told not to. Probably the same outfit.