Miniature and Low-Cost Devices for the Precise and Reliable Monitoring of Low Concentrations of Air Pollutants in Changing Environments

Author： Pereira-Rodrigues Nazaré Guillot Jean-Michel Fanlo Jean-Louis Aubert Bruno

Publisher： Water Environment Federation

ISSN： 1938-6478

Source： Proceedings of the Water Environment Federation, Vol.2010, Iss.3, 2010-01, pp. : 886-894

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Abstract

Gas detection instruments are increasingly needed for individual and industrial health and safety, environmental monitoring and process control. International recommendations and laws for limiting environmental pollution (toxic and malodorous gases) are becoming stricter for both industrial and domestic sources of pollution. Public organizations for environmental control and industries require therefore new tools for a cheaper and more effective monitoring of gas emissions. Today the most common industrial gas sensors available on the market are based on semiconductor oxides. However, issues with sensitivity (ppb range), selectivity and stability have limited their use, often in favor of more expensive approaches. Another limitation of these commonly used gas sensors is their lack of reliability while measurements are made in the field, especially during rapid changes of environmental conditions (like sudden variations of relative humidity).We developed an ultraportable and low-cost monitoring gas device called Observ'Air that allows the continuous detection of low concentrations of gas pollutants, in our case ozone (O₃) and nitrogen dioxide (NO₂) gases due to their high harmful impact on human health:The selectivity of measurement was obtained with specific amperometric gas sensors which have also the advantage to be low consumers of energy and to be miniaturized.The sensitivity of detection was enhanced (from ppm to ppb range) thanks to a dynamic uptake of the target gas to the amperometric sensor (the ppb range was obtained for a combined measurement of O₃ and NO₂ gases).The reliability of measurement was improved by using a filter based on a buffer effect against any environmental interference (like rapid change of relative humidity) during gas monitoring.The low-cost of the developed device provides a higher potential to install arrays of devices in way to map pollutant levels in extended areas.