Physical and chemical properties of airborne nanoscale particles and how to measure the impact on human health

Abstract Suspended particles with a diameter below 1 μm act as vehicles transporting toxic chemicals into the human respiratory system. It is therefore of interest to record the intensity of these particles and to determine the source from which they were emitted. It is shown that this can be done by simultaneously measuring the light scattering (LS), the photoelectric charging (PC), and the diffusion charging (DC). Particles carrying polycyclic aromatic hydrocarbons (PPAH) are detected by their large PC and are generated in combustion of organic materials, whereas particles from other sources only exhibit LS and DC. With combustion-generated particles, the ratio of PC/DC allows to determine the type of combustion from which the particles were emitted. In particular, particles from diesel emission can be distinguished from cigarette smoke. It is further demonstrated how changes of chemical composition or of particle size that might occur in the atmosphere are detectable. As an example of an application, we studied the nanoscale particles found on motorways in the industrialized world. The sources of the majority of these particles are diesel motors. The fraction of particle mass due to PPAH is independent of location and weather conditions. However, the particle concentration is much larger in Tokyo and in Paris than in Zurich due to the higher density of diesel vehicles.

[1]  K. Siegmann,et al.  The Formation of Carbon in Combustion and how to Quantify the Impact on Human Health , 1997 .

[2]  M. Tang,et al.  Preferential Formation of Benzo[a]pyrene Adducts at Lung Cancer Mutational Hotspots in P53 , 1996, Science.

[3]  H. Burtscher,et al.  Photoelectric quantum yield of nanometer metal particles , 1993 .

[4]  H. Burtscher,et al.  Hygroscopic properties of carbon and diesel soot particles , 1997 .

[5]  N. Boccara,et al.  Polycyclic aromatic hydrocarbons and astrophysics , 1986 .

[6]  Peter Schurtenberger,et al.  Enormous Yield of Photoelectrons from Small Particles , 1980 .

[7]  H. Burtscher,et al.  Monitoring PAH-Emissions from Combustion Processes by Photoelectric Charging , 1994 .

[8]  S. J. Cyvin,et al.  Advances in the Theory of Benzenoid Hydrocarbons , 1990 .

[9]  R. Harrison,et al.  Optical and dynamical properties of fractal clusters of carbonaceous smoke , 1989 .

[10]  David A. Williams,et al.  The infrared spectrum of interstellar dust: Surface functional groups on carbon , 1981 .

[11]  Werner A. Stahel,et al.  Aerosol emission in a road tunnel , 1997 .

[12]  K. Sattler,et al.  Reactive Dimerization: A New PAH Growth Mechanism in Flames , 1995 .

[13]  L. Allamandola,et al.  Benzenoid Hydrocarbons in Space: The Evidence and Implications , 1990, Advances in the Theory of Benzenoid Hydrocarbons.

[14]  Alexander G. G. M. Tielens,et al.  Polycyclic aromatic hydrocarbons and the unidentified infrared emission bands - Auto exhaust along the Milky Way , 1985 .