We investigate the effects of enhancements in biogenic VOC emissions on tropospheric carbon monoxide (CO) over North America and the western North Atlantic Ocean during July 2006. This analysis is performed using the 3D Regional chEmical trAnsport Model (REAM) along with the data from TES on the NASA Aura satellite, MOPITT on the NASA Terra satellite, and surface monitor data from the SEARCH network. The key factors affecting summertime CO variations and continental outflow from North America are evaluated. The REAM simulations exhibit large enhancements in column CO observed by MOPITT and lower tropospheric CO seen by TES due to biogenic VOC emissions over the southeastern United States and the western Atlantic Ocean in the hot summer of 2006, which is the 3rd warmest on record. They are used to analyze the spatial impacts of biogenic sources on the lower and free tropospheric CO (<70 ppbv) from the TES measurements. The regions of enhanced CO observed from in-situ ground and satellite measurements during the summer are primarily driven by biogenic-derived CO productions, with the impact of biogenic sources larger than that of anthropogenic sources. The relative importance of biogenic sources over anthropogenic sources over the United States, Canada, and their neighboring Atlantic Ocean is becoming greater as fossil fuel CO emissions decreases. In addition, lower and upper tropospheric CO enhancements due to biogenic sources and stereotypical deep convection are found using vertical profiles of TES CO measurements, which are also simulated in REAM. The measurements show that TES CO observations could provide constraints on pollutant outflow from the continents.