An environmental testing system for environmental testing with particulate matter, such as sand and dust, is disclosed. The testing system uses a feeder to feed precise amounts of particulate matter into an injector, which injects the particulate matter into the airflow leading to a test chamber with approximately the same velocity as the surrounding airflow. The feeder may be a loss-in-weight gravimetric feeder, and the injector may be a Venturi valve actuated by compressed air. The system also includes operator protection features, such as an exhaust fan that creates negative pressure when the door to the test chamber is opened, and when particulate matter is dumped into the system. A temperature control system heats and cools the airflow during tests, a pneumatic conveying system moves fluidized particulate matter into and out of the system, and a controller provides automatic control over the system.