Browsing by Subject "Photoacoustic Spectroscopy"

Black carbon is an aerosol that is a product of incomplete combustion, the main sources are anthropogenic, such as internal combustion engines and burning of biomass. It is ideally absorbing across the visible light spectrum. Carbonaceous aerosols have a range of negative effects such as lung diseases in the local population and radiative force on the Earth. Therefore it is important to determine not only the concentration of these aerosol particles but also identify their sources. Typical measurement methods for monitoring of aerosols involves instruments employing a filter based technique such as an aethalometer. The major drawbacks to such instruments are that the time resolution is in the order of some minutes and some form of correction factors must be applied depending variations such as the time of year the measurement and differing compositions of carbonaceous aerosols based on locality. A 3 wavelength cantilever enhanced photoacoustic spectroscopy instrument was developed during this work to detect the absorption of these particles across the visible range. The benefits of using cantilever enhanced photoacoustic spectroscopy are a time resolution in the order of seconds rather than minutes and that no correction factor is required for the measured absorption value for the particles. In this thesis it is demonstrated that multi-wavelength photoacoustic spectroscopy can be used for measuring black carbon aerosols and the information obtained can be used estimate the source of those particles.