World Health Organization considered air pollution the most dangerous threat to human health. This paper presents a novel system to mitigate risks derived from polluted air by introducing a portable device for vulnerable people able to detect hazardous pollution concentration and to suggest healthy behaviors. Along with the device, a tailored web server application, called Monitoring Outdoor Quality of Air (MOQA), is developed. The application will make the data collected from the device’s sensors more readable and will provide citizens with air quality information. That information will alert vulnerable people about air pollution hazards and let them take actions consequently. This system can reduce the health risks derived from air pollution for the weakest population in the short-term.