Occupational Exposure to Ultrafine Particles among Airport Employees - Combining Personal Monitoring and Global Positioning System

Background

Exposure to ultrafine particles (UFP) has been linked to cardiovascular and lung diseases. Combustion of jet fuel and diesel powered handling equipment emit UFP resulting in potentially high exposure levels among employees working at airports. High levels of UFP have been reported at several airports, especially on the apron, but knowledge on individual exposure profiles among different occupational groups working at an airport is lacking.

Purpose

The aim of this study was to compare personal exposure to UFP among five different occupational groups working at Copenhagen Airport (CPH).

Method

30 employees from five different occupational groups (baggage handlers, catering drivers, cleaning staff and airside and landside security) at CPH were instructed to wear a personal monitor of particle number concentration in real time and a GPS device. The measurements were carried out on 8 days distributed over two weeks in October 2012. The overall differences between the groups were assessed using linear mixed model.

Results

Data showed significant differences in exposure levels among the groups when adjusted for variation within individuals and for effect of time and date (p<0.01). Baggage handlers were exposed to 7 times higher average concentrations (geometric mean, GM: 37×10³ UFP/cm³, 95% CI: 25–55×10³ UFP/cm³) than employees mainly working indoors (GM: 5×10³ UFP/cm³, 95% CI: 2–11×10³ UFP/cm³). Furthermore, catering drivers, cleaning staff and airside security were exposed to intermediate concentrations (GM: 12 to 20×10³ UFP/cm³).

Conclusion

The study demonstrates a strong gradient of exposure to UFP in ambient air across occupational groups of airport employees.     

Current progress in use of adipose derived stem cells in peripheral nerve regeneration

Unlike central nervous system neurons; those in the peripheral nervous system have the potential for full regeneration after injury. Following injury, recovery is controlled by schwann cells which replicate and modulate the subsequent immune response. The level of nerve recovery is strongly linked to the severity of the initial injury despite the significant advancements in imaging and surgical techniques. Multiple experimental model shave been used with varying successes to augment the natural regenerative processes which occur following nerve injury. Stem cell therapy in peripheral nerve injury may be an important future intervention to improve the best attainable clinical results. In particular adipose derived stem cells(ADSCs) are multipotent mesenchymal stem cells similar to bone marrow derived stem cells, which are thought to have neurotrophic properties and the ability to differentiate into multiple lineages. They are ubiquitous within adipose tissue; they can form many structures resembling the mature adult peripheral nervous system. Following early in vitro work; multiple small and large animal in vivo models have been used in conjunction with conduits, autografts and allografts to successfully bridge the peripheral nerve gap. Some of the ADSC related neuroprotective and regenerative properties have been elucidated however much work remains before a model can be used successfully in human peripheral nerve injury(PNI). This review aims to provide a detailed overview of progress made in the use of ADSC in PNI, with discussion on the role of a tissue engineered approach for PNI repair.