Kiwfo, K.; Grudpan, K.; Held, A.; Frenzel, W. Smartphone-Based Color Evaluation of Passive Samplers for Gases: A Review. Atmosphere2024, 15, 451.
Kiwfo, K.; Grudpan, K.; Held, A.; Frenzel, W. Smartphone-Based Color Evaluation of Passive Samplers for Gases: A Review. Atmosphere 2024, 15, 451.
Kiwfo, K.; Grudpan, K.; Held, A.; Frenzel, W. Smartphone-Based Color Evaluation of Passive Samplers for Gases: A Review. Atmosphere2024, 15, 451.
Kiwfo, K.; Grudpan, K.; Held, A.; Frenzel, W. Smartphone-Based Color Evaluation of Passive Samplers for Gases: A Review. Atmosphere 2024, 15, 451.
Abstract
The application of smartphone-based color evaluation of passive sampling devices for gases has only been sparsely reported. The present review aims to compile available publications with respect to the configuration of the passive samplers, conditions of smartphone photographing, analytical procedure for color detection and quantification (including calibration processes), and their application to different target gases. The performance of the methods - whenever available - is presented regarding the analytical specifications selectivity, sensitivity, and limit of detection in comparison with other color evaluation methods of passive samplers. Practical aspects like requirements of instrumentation and ease of use will be outlined in view of the potential employment in education and citizen science projects. In one section of the review the inconsistent terminology of passive and diffusive sampling is discussed in order to clarify the distinction of information obtained from the uptake of the passive samplers between gas-phase concentration and the accumulated deposition flux of gaseous analytes. Colorimetric gas sensors are included in the review when applied in passive sampling configurations and evaluation is performed with smartphone-based color evaluation. Differences in the analytical procedures employed after the passive sampling step and prior to the detection of the colored compounds are also presented.
Keywords
Passive gas sampling; diffusive sampling; ambient air measurements; immission rate; smartphone-based color evaluation; RGB color space; colorimetric gas sensors
Subject
Environmental and Earth Sciences, Pollution
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
