The present application discloses a device for detecting and reducing radon concentration in an indoor environment. This device comprises at least one radon gas sensor and, at least one differential pressure sensor for measuring the difference between the indoor and outdoor atmospheric pressures, wherein both sensors are connected to a microcontroller configured to perform the pre-processing and aggregation of the data obtained by said sensors. To reduce radon levels, it triggers at least one physical actuator to activate a ventilation device for reducing the radon concentration in an indoor environment when indoor radon concentration is above a first predetermined threshold or when indoor radon concentration is above a second predetermined threshold and the differential pressure is negative.