Mobile monitoring of air pollution using low cost sensors to visualize spatio-temporal variation of pollutants at urban hotspots

This paper deals with the development of a smart personal air quality mon- itoring system (SPAMS) for real time air quality monitoring. The commer- cially available low-cost CO, NO2, O-3, PM, temperature (T) and humidity (RH) sensors along with the microcontroller and GPRS were integrated in SPAMS. The developed SPAMS was calibrated in the laboratory and vali- dated through field measurements. Field measurements were performed by walking on footpaths and travelling in the bus during various times of a day and different days in a week at selected locations in Chennai city, India. Re- sults indicated that the PM2.5 concentration was highest in busy traffic site (mean = 22.7 +/- 8.45 mu g/m(3)) and lowest in urban background (mean = 9.3 +/- 5.75 mu g/m(3)). Whereas, the CO concentration was lowest at beach road (mean = 0.26 +/- 0.01 ppm). Not much variation was observed in the average concentrations of NO2 and O-3. On the other hand, while travelling in buses, higher concentration of CO and NO2 were observed during the morning and evening periods due to the peaking traffic flow. On contrary O-3 concentration was found to be highest during afternoon due to photochemical reactions.