Carbon Monoxide (CO) is the most abundant air pollutant gas and accumulates rapidly to dangerous concentrations even in areas that seem to be well ventilated. Carbon monoxide detectors/alarm systems exist but people who are old, hearing impaired, partially sighted or heavy sleepers may not get the warning or find it difficult to wake up and get out in the event of dangerous concentration of CO in their homes. This paper presents the development of a smart CO monitoring and control system to control the ventilation in a room when carbon monoxide concentration is at a level dangerous to human health. The system is comprised of a microcontroller interfaced with CO sensor (MQ-7) and ultrasonic distance sensor (HC-SR04) for CO concentration sampling and window state determination respectively. A third component interfaced with the controller is a DC motor, which accordingly control the window when the concentration of CO is high. A mechanism was provided to ensure that the fan in the room is ON and the window is completely open whenever CO concentration is high to ensure quick restoration of the air quality. Results from the performance evaluation of the system showed that it achieved an average response time of 6 seconds and consumed 321.62mW and 652.82mW of power during sampling and control respectively. The obtained results showed that the system is capable of responding quickly to dangerous concentration of CO, thus a desired attribute of CO monitoring systems hence, can adequately replace the existing systems with less power consumption.