  In many countries around the world, most of the waste use to be disposed of
to landfills, this generate public concern about the health effects of
emissions. Landfill gases are produced by the natural bacterial decomposition
of waste and it is about half of methane, with the remainder mostly carbon
dioxide and minor amounts of other gases. Real-time measurement and modelling
of emissions gases in landfills is important. In this work a low cost wireless
measurement system is developed using MOS gas sensors (MQ4-1,MQ4-2, MQ5 and
MQ9), microcontroller and XBee/HC-12 wireless communications modules. The
system can be mounted on an unmanned aircraft (UAV, drone) or deployed as a
wireless sensor network. Experiments have been carried out near a closed
landfill, which show high gas concentration
