ABSTRACT: In Thailand and many other Asian countries, where rice is the major crop, open burning of rice straw after harvesting is a common practice. This activity releases a large amount of air pollutants, which can cause serious effects on the ambient air quality, public health and climate. In this study, the number of hotspots, which represents open fires, detected on the Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images over the Pathumthani were counted. The results show high numbers of hotspots during the rice straw burning season. Good correlation was obtained between hotspots numbers and the levels of air pollutants, including carbon monoxide and particulate matter, measured at the Rangsit ground based air quality monitoring station of the Pathumthani province. Forward trajectories were calculated using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT4) model to roughly examine possible transport pathways of smoke emitted from the rice straw burning in Pathumthani. The results show that during the intensive burning season (November-April) smoke plumes from rice straw burning in Pathumthani can be transported to Bangkok following the Northeast monsoon. Emission from open rice straw burning therefore may contribute significantly to air pollution levels in the surrounding areas including Bangkok.