7.4.4 Electrochemical Sensors for Environmental Monitoring in Cities

R.L. Jones, G. Stewart, O. Popoola, I. Mead & J. Saffell
We demonstrate that miniature, low-cost electrochemical gas sensors, traditionally used for sensing at parts-permillion (ppm) mixing ratios can, when suitably configured and operated, be used for parts-per-billion (ppb) level studies for gases relevant to urban air quality. The results show the sensors to be high precision and highly linear in the ppb rangeand in general highly selective, although there are some significant cross-interferences. Comparisons of the sensors with co-located reference instruments show good agreement on...