Environmental Monitor Service Inc. is a leader in the field of advance technology Opacity and Dust Monitor Systems. EMSâ€™ EPA Compliant Opacity and Non-compliant Opacity Monitors are guaranteed to exceed CFR 40, Part 60 Performance Specification 1 for Opacity Monitors as well as ASTM D 6216. We offer a wide variety of models to fit every budget and suit any application. All of our monitors are set up and tested at the factory to meet the site specific dimensions that the customer has provided. This, along with our user-friendly design assures a quick, trouble free installation.