Development of low-cost spectroscopic techniques for measuring Nitrogen Dioxide in urban environments
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Full Text E-thesis
Date
2024
Authors
Halpin, Eibhlín Francis
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Publisher
University College Cork
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Abstract
Nitrogen dioxide (NO2), a priority air pollutant in Ireland, is a toxic gas released during combustion processes, making traffic and transport major sources in urban environments. Commercial NO2 monitors used by official monitoring bodies have low spatial resolution and do not capture the complex distribution of NO2, particularly in the presence of mobile sources, like vehicles, and low-cost electrochemical NO2 sensing is not accurate or reliable enough for consistent air pollutant monitoring.
In this thesis, spectroscopic techniques were explored for achieving selective and sensitive NO2 measurements at a reasonably low cost using LED light sources and non-dispersive detectors for in situ or remote applications. Two-channel spectroscopic methods were simulated, and a narrowband two-channel system was tested in an atmospheric simulation chamber to confirm a response to NO2, however, this system was not sensitive to ambient NO2 levels without appropriate signal amplification.
A single-channel wideband instrument was therefore built with improved sensitivity but reduced selectivity to NO2. The single-channel instrument was used to measure ambient NO2 near a primary school in Cork City to assess the feasibility of capturing NO2 concentrations with high temporal resolution at a relatively low cost. The effect of school traffic on local NO2 emissions was explored in the context of a street canyon microenvironment.
This work aims to bridge the gap between expensive NO2 monitoring systems and unreliable low-cost sensors and discusses the future development of a lower cost two-channel NO2 detector with a recommended instrument design and approximate cost analysis.
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Keywords
Nitrogen dioxide , Low-cost sensing , Spectroscopy , Urban measurement
Citation
Halpin, E. F. 2024. Development of low-cost spectroscopic techniques for measuring Nitrogen Dioxide in urban environments. PhD Thesis, University College Cork.