Encompassing Computer Science Workshop 2015

Spectral analysis of particulate filters: the initial findings

Not scheduled

Description

Particulate matter (PM10) is an important indicator of air pollution. PM10 particles are solid and liquid droplets smaller than 10 microns in diameter. Not only mass concentration (mass per volume), but also chemical composition may reveal environmental and health risks. One of the components whose concentration is of greater interest is black carbon. Black carbon concentration can be determined by measurement of aerosol light absorption in the visible spectral range. Having access to particulate filters used in the process of weighting daily concentrations of PM10 for two measurement stations in Port of Koper we performed their spectral analysis. We have acquired images of reflected light spectrum using an image spectrograph mounted to an industrial camera for daily particle filters for one year and for both available measurement stations. Although the spectrograph enabled wider spectral range, the relative filter spectrum was estimated only for the visual light wavelengths, due to limitations of the camera used. In contrast to our initial expectations we did not detect important spectral variations; on the contrary, the only observed difference among filters was in spectral attenuation. Comparison of spectral attenuation and PM10 mass concentrations revealed an expected exponential relationship, however with the relatively high residual error. Results were similar for both measurement stations, including the temporal distribution of the residual. Consequently we have also compared spectral attenuations for both stations and the obtained results revealed evidently high correlation. Based on these results we can conclude that in addition to PM10 mass concentration some other characteristics, for example chemical composition, of PM10 influences the spectral attenuation, which we could refer to as particulate brightness. For the future we tend to analyze the relation of particulate brightness with other environmental properties that could eventually enable us to draw conclusions of the particulate sources or even chemical composition.