Measuring Concentration Of Ice Nucleating Particles In The Atmosphere Particulate Matters And Gaseous Pollutants In Museums Insight From Models And Elemental Analysis.

Ice nucleation in clouds affects the optical thickness and lifetime of mixed-phasernclouds and is responsible for a significant proportion of precipitation formed globallyrnand ultimately indirectly affect climate. In mixed-phase clouds, where temperaturesrnrange from −370C and 00C, ice crystals can only form on certain aerosol particles.rnIce nucleating particles (INPs) constitute such aerosols with reduce energy barrierrnof ice nucleation. Despite significant advancement in the fundamental understandingrnof different ice formation processes in the last decades, the ice phase in cloudsrnstill contributes major uncertainties in climate model prediction of radiative forcing.rnThis is partly due to a limited understanding of the behaviour of aerosol particlesrnto act as INPs and paucity of observational data in the atmosphere quantifying INPrndistributions. Therefore, the first part of this employed Micro-liter Nucleation by ImmersedrnParticle Instrument (μ-NIPI) to cool down droplets containing ice-nucleatingrnmaterial at a controlled rate and to monitor their freezing temperatures. The experimentsrnreveal that aerosol droplets started to freeze at −140C down to -250C;while,rnthe concentration evolved from 0.1 to 10−3 cm−3. The average temperature in whichrn50% of the droplets froze occurred at −200C with a concentration of 10−3 cm−3. Thernexperimnets have shown that the type of aerosol species that make INPs in Leeds,rnUK, were dominantly feldspar from mineral dust. Moreover, meteorological factorsrnsuch as wind speed, temperature and relative humidity affected INPs’ concentrations.rnIn addition to the aforementioned aerosol radiative forcing (climate forcing), aerosolrnhas significant impact on the environment (e.g., air and water pollution). In fact, pollutionrnis not a phenomenon just of modern time; it is intimately connected with thernxivrndawn of the industrial age in which the effects of particulate matter and gaseous pollutantsrnon precious cultural assets become obvious. The high atmospheric load causedrnstrong soiling as well as corrosion outdoors and indoors. The increasing attractionrnon indoor pollutants in the museums environment and associated investigation contributernto the understanding of basic mechanisms. Particulate matter and gaseousrnpollutants are involved in deterioration processes and aging mechanism was not realizedrnuntil macroscopic observable damages occurred which gave the starting point forrnscientific investigation. Therefore, in the second part of this work, particulate matterrnsamples were collected on Teflon membrane filters using Harvard-type Impactor collector,rnAethalometry and diffusive sampler are to measure black carbon and gaseousrnpollutants respectively. It was observed that the daily PM10 average mass concentrationsrninside and outside the Magritte and Reserve OB museums-varied betweenrn2.71 and 5.25 μg/m3 with an average concentration of 4.10 μg/m3 and 0.36 andrn7.75 μg/m3 with an average concentration of 2.20 μg/m3 respectively. The concentrationsrnwere usually lower when the museum was closed and there were no touristrnactivities around. Inside the museums, mass concentrations were much less thanrnoutside with daily variations, which were due to wind speed, wind direction, humanrnactivity and traffic activities outside of the museums. The average mass concentrationsrnof indoor PMs were always lower than that of the outdoor ones that as reflectedrnin low indoor/outdoor ratios indicating that the sources of pollutants were from outsidernthe museums. Particle number concentrations in all sizes (i.e., PM1, PM2.5 andrnPM10) remained at high levels during morning time which are correlated directly withrntemperature and inversely with relative humidity. Furthermore, the concentrationsrnof gaseous pollutants (NO2, SO2 and O3) were lower inside the museums than thernoutside with some of them at undetectable levels; in addition, the levels of these gasesrninside the two museums were lower and below the recommended level when comparedrnto that of other museums. Bulk aerosol samples of different sizes were analyzed byrnmeans of energy-dispersive X-ray fluorescence analysis (EDXRF) to determine theirrncomposition. The analysis led to identification of 11 elements (Al, Si, P, S, Cl, K, Ca,rnxvrnMn, Fe, Cu and Zn). The levels of concentrations of these elements were found tornbe 27.45 and 281.85 ng/m3 at Magritte and 16.16 and 154.26 ng/m3 at Reserve OBrninside and outside of the museums on average respectively; their sources were predominantlyrnanthropogenic from traffic activities and industries. It was observed thatrnair mass with trajectories emanating from maritime and continental sources severelyrnaffected the concentrations pollutants in the museums

Get Full Work

Report copyright infringement or plagiarism