Design, build and initial tests of a portable methane measurement platform

The quantification of methane concentrations in air is essential for the quantification of methane emissions, which in turn is necessary to determine absolute emission and the efficacy of emission mitigation strategies. These are essential if countries are to meet climate goals. Large scale deployment of methane analyzers across the millions of emission sites is prohibitively expensive and lower-cost instrumentation has been recently developed as an alternative.  Currently, it is unclear how cheaper instrumentation will affect measurement resolution or accuracy.  To test this, the Wireless Autonomous Transportable Methane Emission Reporting System (WATCH4ERS) has been developed and comprises four commercially available sensing technologies: Metal Oxide (MOx,); Non-dispersion Infrared (NDIR); Integrated Infrared (INIR); and Tunable Diode Laser Absorption Spectrometer (TDLAS).  WATCHERS is the accumulated knowledge of several long-term methane measurement projects at Colora..., The WATCH4ERS comprises five individual methane sensors (two MOx sensors, NDIR sensor, INIR sensor and a TDLAS) that stream data to a single laptop PC via a powered USB hub.  Data are read into the PC using Python code and data are stored locally.  
The code required to run the WATCH4ERS can be found at https://github.com/stuartnriddick/AMMMU.git.  Three Arduino UNO’s are used to interface the MOx sensors, the ’46 Hawk (TDLAS sensor) and the environment monitoring sensor (DHT22) to the data logging PC through a standard USB port. For the TGS2600 and TGS2611 metal oxide sensors, an Arduino UNO along with an Adafruit ADS1115 ADC interfaces the sensors and the code “Riddick MOX Arduino Code.ino” controls the sampling of these sensors and the transfer of the data to the PC.  The ’46 Hawk sensor does not have any digital output and the data from this instrument is extracted by a technique known as “data sniffing” where code run by the monitoring Arduino interrogates the ’..., , # Design, build and initial tests of a portable methane measurement platform

[https://doi.org/10.5061/dryad.gf1vhhn0j](https://doi.org/10.5061/dryad.gf1vhhn0j)

## Description of the data and file structure

An experiment was conducted where 0.5% methane was released at 5 liters per minute 0.5 m upwind of a WATCH4ERS unit.  Air flow between the release point and the WATCH4ERS unit was controlled at 3.5 m s-1 using a fan blowing at a constant rate.  Five experiments were conducted to investigate the response of the MOx, NDIR, INIR and TDLAS sensors.  In each experiment, three gas plumes were released from a cylinder for a fixed duration with a controlled time between the plume release.  The aims of the experiment are to determine: 1. How many of the plumes could be seen in the instruments’ methane concentration data; 2. The typical time taken to respond to a downwind plume; and 3. The typical methane concentrations observed downwind.
### Files and variables

#### File: Riddick\_WATCH4ER...,