|M.Sc Thesis||Department of Civil and Environmental Engineering|
|Supervisors:||Assoc. Prof. Broday David|
|Assoc. Prof. Dubowski Yael|
|Full Thesis text - in Hebrew|
Aerosols play a major role in the atmosphere. They affect the Earth radiative balance directly, by scattering and absorbing solar and terrestrial radiation, and indirectly, by affecting the structure and development of clouds. Furthermore, many epidemiological studies report on associations and even dose-response relationships between PM10 (particulate matter with diameter less then 10 µm) and various adverse health outcomes.
The main objective of this research was to examine the spatial concentration variation of fine and coarse particulate matter and of their water soluble fraction of particulate organic carbon (WSOC), total organic carbon (OC) and elemental carbon (EC) in Haifa bay area. Some samples were also analyzed for water soluble metals. Six campaigns were performed as part of this work, each lasted about 10 days with sampling intervals of 12 or 24 hours. The sampling took place at different sites in parallel using identical instruments. However, different sampling devices (High Volume Samplers, Dichotomous Medium Volume Samplers, URG Low Volume Samplers) were used in different campaigns, in relation to the PM fraction and compositional analysis performed. The samplers were deployed in the vicinity of main traffic routes (Yagur junction and Ahuza junction) and at sites that are distant from major emission sources (Haifa university, Technion, and the residential neighborhood of Neve Shaanan).
Particulate matter concentrations of the PM10 and PM2.5 fractions were higher at sites close to emission sources relative to locations farther away from them. During daylight hours, PM concentrations were higher than at night, probably since anthropogenic emissions and formation of secondary aerosols peak during daytime. OC and EC concentrations were higher in the vicinity of roads compared to sites farther away from main traffic routes. The fractions of the WSOC out of the PM (WSOC/PM) and of the WSOC out of the OC (WSOC/OC) concentrations were found to be higher in sites farther away from the major emission sources/sites in the area. This variability between the sampling stations suggests that aging processes of aerosol (e.g., photo-oxidation) can be significant even on the time scale of dispersive processes in the urban region. Extreme (high and low) PM concentration episodes were found to be primarily related to exceptional meteorological conditions, such as dust storms and rain events.