Development of Low-Cost Ozone and Nitrogen Dioxide Measurement Instruments Suitable for Use in An Air Quality Monitoring Network

We demonstrate low-cost ozone and nitrogen dioxide measurement instruments suitable for use in an air quality monitoring network. The instruments are based on the gas response of semiconducting oxides at elevated temperature. Although there is a perception that the devices suffer from effects such as drifts of zero and calibration slope, and cross-sensitivities to other gases making them unsuitable for quantitative, long-term atmosphere measurement, we have shown that with careful attention to detail based on a thorough understanding of the mechanisms underpinning device operation, these perceived deficiencies can be overcome. The resultant instruments are small, robust, have sensitivity for O3 and NO2 less than 10 part-per-billion, and track reference analysers in the atmosphere to better than {plus minus}10% over periods of months, without recalibration.