Real-time Nitrogen Oxides Measurements at Low ppb Levels

There has always been a difficulty in accurately quantifying benzene, toluene, ethylbenzene, ortho-, meta-, and para-xylene (BTEX) and nitric oxide and nitrogen dioxide (NOx) gases in a portable format. The DV3000 UV Gas Analyser from Duvas Technologies has the ability to accurately analyse a wide range of gases, including BTEX and NOx, simultaneously to ppb levels without cross-interference between species. It uses closed path spectroscopy and a DOAS-based technique to feed emission data to an advanced algorithm. Each species corresponds to a unique absorption spectrum; the algorithm is able to match the species via this ‘fingerprint’ allowing for detection and differentiation between species in complex mixtures. Using high performance Lithium battery packs, field surveys can be performed for up to six hours. These packs can easily be hot-swapped during analysis for uninterrupted operation and prolonged field deployment. The HEPA filter and mesh system prevents mirror contamination from particles greater than 0.8 microns.

In the examples shown, a DV3000 instrument was used to perform a survey of public roads around two refineries in Grangemouth in the UK in January 2017. The instrument was mounted in an automobile and driven around the plants where it was Bluetooth and GPS enabled, allowing for results to be viewed in real time on an Android tablet during the analysis of the areas. Additionally, this feature allows for data to be pinpointed to an exact location during the reprocessing of data at a later time. The highest NO levels were close to 800 ug/m3 or approximately 650 ppb, while NO2 levels peaked to 2300 ug/m3, approximately 1225 ppb.