This paper presents a measurement system to greenhouse gases (GHG) monitoring. GHGs are formed by the emission of Carbon Dioxide (CO2) and Methane (CH4) from vehicles and near located landfills in Juliaca city in Perú. A wireless system is developed using MOS sensors (MQ2, MQ4, TGS2611 and MQ-135), Arduino-nano, XBee wireless communications modules and the interface to the computer is written in Python. The system was tested in real field measurements and the results show gas concentration difference in different points of the city. We could observe that the CO2 content in places with a large number of vehicles is high and places with organic waste, like fresch product market, the CH4 content is also high.