Inconvenient measurements of escaping gas

With environmental issues such as the enhanced greenhouse gas effect, acidification or air pollution, it’s all about gas and particles entering the atmosphere. This can occur from a “point source“ like a chimney which is relatively easy to measure. Measurements are much harder for so called diffuse sources. Farms, industrial installations, landfills or swamps are examples.

Arjan Hensen, researcher at ECN, presents his paper about ‘Diffuse sources’ at VU in Amsterdam January 12. He explains: ”These sources cover large areas and the emission is variable in time. The emission from a m2 on a landfill can differ by a factor of 1000 with the emission a few meters away. So, how to get an annual emission  for a 60 hectare landfill?.” 

Still 20% of the NL-greenhouse gas emissions and 80% of the ammonia emissions originate from these sources. There are several measurement methods that range from boxes placed on the soil, to fast response sensors driving through the “gasplume” to measure the emission from a source. Hensen shows the measurement methods, their shortcomings and how improvements can be made. There is something to gain: the uncertainty in the greenhouse gas emission level for the Netherlands for example is still dominated by nitrous oxide from soil and water, methane from cows and landfills. These are all diffuse source systems. According to Hensen innovation of sensors and methods is the key to reduce these uncertainties. Observations bring new knowledge, is therefore the final conclusion. After all, governments and industries need reliable measurement data in reducing emissions to achieve sustainability.

You can download the paper here.

For more information about the measurements of greenhouse gas emissions by ECN you can view the film "Measuring emissions from diffuse sources".

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