טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentInibtawi Maisa
SubjectContent of Combustion Retardants in Cars' Dust
DepartmentDepartment of Civil and Environmental Engineering
Supervisors Professor David Broday
Professor Yael Dubowski
Full Thesis textFull thesis text - English Version


Abstract

Brominated flame retardants (BFRs) have routinely been added to consumer products for several decades in a successful effort to reduce fire-related injuries and property damages. Polybrominated diphenyl ethers (PBDEs) are commercially produced in three forms: pentaBDE, octaBDE and decaBDE. Polybrominated diphenyl ethers (PBDEs) are mostly used as additive chemicals, making them more susceptible to leaching overtime, and can be found in many components of the vehicle interior. Due to the high temperatures that can be attained inside cars that are parked in the sun, this microenvironment may be important with regard to PBDE exposure. This research quantified three common flame retardants (BDE-47, BDE-99, BDE-209) in car dust as a function of the season, car manufacturer and parking environment. The photodegradation of these compounds was also examined. Measurements in 11-16 cars took place in four seasons. High levels of total PBDEs were observed in the summer (18.6±10.2 µg˖g(dust)-1) without showing a clear pattern for the vehicle manufacturer, model or age. The lowest levels of total PBDEs were observed in the spring, together with the highest relative concentrations of BDE-209. BDE-209 concentrations dropped in summer, probably due to debromination to lower congeners. Hence, debromonation of the selected BDEs (sorbed on glass fiber filter and on smooth glass) was further studied under ambient sunlight conditions. First order kinetic models were fitted to the data for estimating the decay coefficients for BDE-47, BDE-99 and BDE-209. Debromination process had better dependency on actinic flux than on time as an explanatory variable. To simulate the formed PBDEs behavior, a model was developed by using the decay coefficients which were obtained during the laboratory experiments . The model also provided an estimation of the formation yield of formed PBDEs. These results are the first to be reported in Israel as well as for the Israeli Mediterranean climate. Although vehicles were found to be an important microenvironment for PBDEs exposure in the Israeli climate, further research is needed for assessing exposures to PBDEs during commute in cars.