Air and Atmosphere
Air pollution and modelling of atmospheric dynamics are among the fastest growing fields of interest, even excluding global change. The air and atmosphere group deals with physical and chemical processes related to the atmosphere at the local to regional scales. This includes regional studies of particles pollution dynamics, local studies of energy movement within buildings, computational fluid dynamics, atmospheric chemistry and environmental health.
Computational Fluid Dynamics
Turbulent flows with stable stratification and rotation are analyzed using turbulent flow models. Density jumps are investigated using both simplified models and the CFD Model FLUENT. The environmental impact of energy towers as well as the influence of the environmental parameters on the operation of the energy tower is investigated using simplified models and the CFD program FLUENT.
Energy in Buildings and Renewable Energy Sources
Researchers have developed THERMO/KAR, a program for checking the compliance of building elements and houses with the Israeli Thermal Insulation Standard (1045), and for calculating their cooling and heating consumption in buildings. Hybrid ventilation measurement and analysis in urban environments has been investigated in the framework of an EU-funded project. The performance of energy towers – a method of renewable energy production by exploiting the potential energy of air cooled by water evaporation in a 1000 meters - .was investigated using a variety of methods, including scaled models and CFD simulations using the FLUENT Program.
Research activities focus on source apportionment, transport and deposition of atmospheric particles; as well as application and development of advanced electron microscopy techniques to characterize atmospheric individual particles, using morphology and elemental composition of single particles.
Air Quality and Environmental Health
Various research activities are performed in the fields of air quality and environmental health. Data mining tools are developed and applied for identifying signatures of emissions and physical processes in air quality monitoring data. Activities in this area include (i) development of general tools to characterize and parameterize processes that affect outdoors air quality by means of extracting signatures of the processes that govern the fate of ambient pollutants from monitoring databases, and (ii) application of these tools using records collected in Israel. Among the topics studied are the contribution of power plants and industrial emissions to observed ambient concentrations and the impact of traffic on urban air quality. Recently, such tools were used for assessing chronic exposure to traffic-related air toxics in an urban environment and for investigating source allocation and the impact of distinct sources and episodic events. Spatial statistics tools, embedded in a GIS platform, for exposure assessment have also been developed and applied. Studies included urban-scale variability of ambient particulate matter due to removal and oxidation/aging processes, heterogeneous source distribution and topographical and land-use variations. In a recent study, pollutant concentrations were linked with the heterogeneous demographic distribution. Resulting risk metrics were used in an environmental epidemiology study. Researchers create models for transport and deposition of particles within the human respiratory tract. The effect of lung morphology, breathing parameters, particle physicochemical properties (size, morphology, hygroscopicity) and particle-particle interactions (screening effect) on the deposition of respirable particles along the human respiratory tract are studied. Results are linked and interpreted in relation to exposure and risk estimation. Particular attention is given to ambient ultrafine particles and to engineered nano-particles. Remote sensing methods for measurement of ambient particulate matter and for assessing population exposure to airborne PM are being developed. Activities in this area are focused on developing (i) a hyper-spectral imaging technique for urban-scale open path measurement of ambient particles at night, and (ii) methodologies for integration of satellite-borne remotely sensed aerosol optical thickness with ground monitoring data for environmental health applications.
Atmospheric chemistry research here focuses mainly on the indoor and outdoor outcome of air pollutants. This includes quantitative investigations of their interactions with atmospheric oxidants and solar radiation, both in the gas and aerosolized phases as well as at the interfaces between them. The obtained kinetic data and product identification enable modeling of the chemical transformations occurring after introduction of the pollutants to the atmosphere and evaluation of their implications to human exposure. The new Laboratory of Atmospheric Chemistry is equipped with state-of-the-art analytical instruments for both gas phase and aerosol analysis, including a novel system combining ATRFTIR and long-path IR gas cell for simultaneous monitoring of gas and condensed phases. The lab also contains a complete system for generating, sizing and counting of sub-micron aerosols, in combination with long-path IR reactor, allowing real time monitoring of the aerosol spectral signature in the IR region. With regard to atmospheric aerosol sampling, the laboratory is equipped with both high volume aerosol sampler and MOUDI cascade impactor allowing aerosol collections at several size intervals. For chemical analysis of the collected aerosols, we have a gas chromatograph (with FID and MS detectors) and high pressure liquid chromatograph.