Construction of a photocatalytic de-polluting field site in the Leopold II tunnel in Brussels.

Within the framework of the European Life+-funded project PhotoPAQ (Demonstration of Photocatalytic remediation Processes on Air Quality), which was aimed at demonstrating the effectiveness of photocatalytic coating materials on a realistic scale, a photocatalytic de-polluting field site was set up in the Leopold II tunnel in Brussels, Belgium. For that purpose, photocatalytic cementitious materials were applied on the side walls and ceiling of selected test sections inside a one-way tunnel tube. This article presents the configuration of the test sections used and the preparation and implementation of the measuring campaigns inside the Leopold II tunnel. While emphasizing on how to implement measuring campaigns under such conditions, difficulties encountered during these extensive field campaigns are presented and discussed. This included the severe de-activation observed for the investigated material under the polluted tunnel conditions, which was revealed by additional laboratory experiments on photocatalytic samples that were exposed to tunnel air. Finally, recommendations for future applications of photocatalytic building materials inside tunnels are given.

Particle emissions from a marine engine: chemical composition and aromatic emission profiles under various operating conditions.

The chemical composition of particulate matter (PM) emissions from a medium-speed four-stroke marine engine, operated on both heavy fuel oil (HFO) and distillate fuel (DF), was studied under various operating conditions. PM emission factors for organic matter, elemental carbon (soot), inorganic species and a variety of organic compounds were determined. In addition, the molecular composition of aromatic organic matter was analyzed using a novel coupling of a thermal-optical carbon analyzer with a resonance-enhanced multiphoton ionization (REMPI) mass spectrometer. The polycyclic aromatic hydrocarbons (PAHs) were predominantly present in an alkylated form, and the composition of the aromatic organic matter in emissions clearly resembled that of fuel. The emissions of species known to be hazardous to health (PAH, Oxy-PAH, N-PAH, transition metals) were significantly higher from HFO than from DF operation, at all engine loads. In contrast, DF usage generated higher elemental carbon emissions than HFO at typical load points (50% and 75%) for marine operation. Thus, according to this study, the sulfur emission regulations that force the usage of low-sulfur distillate fuels will also substantially decrease the emissions of currently unregulated hazardous species. However, the emissions of soot may even increase if the fuel injection system is optimized for HFO operation.

An on-line method for the reduction of fouling of spin-filters for animal cell perfusion cultures.

The main limitation in the use of spin-filters during perfusion cultures of animal cells was revealed to be filter fouling. This phenomenon involves cell-sieve interactions as well as cell attachment to, and growth on, the filter surface. The cell attachment effect has been analysed in the present study during long-term perfusion simulations with CHO animal cells. It was demonstrated that at low filter acceleration, below 6.2 m/s2, a high perfusion rate of 25 cm/h induced rapid filter pore clogging within 3 days, whereas increasing the filter acceleration to 25 m/s2 increased filter longevity from 3 to 25 days, for filters with a pore size of 8.5 microm. Increasing the filter pore size to 14.5 microm improved filter longevity by 84% with less viable and dead cell deposits on the filter surface. However, it was demonstrated that filter longevity was not necessarily dependent on the amount of cell deposit on the filter surface. In the second part of this study, ultrasonic technology was used to reduce filter fouling. Filter vibration, induced by a piezo actuator, improved filter longevity by 113% during CHO cells perfusion cultures.

[Quality assurance in the diagnosis of indoor fungi]. / Ringversuch "Innenraumrelevante Schimmelpilze".

In co-ordination with the Umweltbundesamt Berlin, the Landesgesundheitsamt Baden-Wurttemberg (LGA) initiated external quality assurance in the diagnosis of indoor fungi in autumn 2001. Four of six fungal strains commonly found indoors have to be fully identified (on the genus and species level). There are two distributions per year; the six distributions hitherto carried out resulted in correct identification by 46-89% of laboratories (40-71 participants, total 148). It is clear from the results that repeat participants were more successful. In addition to the pure cultures sent out we offered actual samples (two air samples, one wood material, one sample of house dust, hitherto); 43- 69% of participating laboratories also took part in this facultative investigation of actual samples and 29-62% were successful. Results that differed considerably revealed problems while treating and evaluating actual samples. Therefore, activities in this field should be enhanced. In conclusion, external quality assurance in the diagnosis of indoor fungi is a useful management aid in the maintenance and improvement of laboratory performance.

[Strategies and targets for establishing a multicenter trial: "Identification of indoor relevant moulds"]. / Strategien und Ziele der Etablierung eines Ringversuchs. "Differenzierung von innenraumrelevanten Schimmelpilzen".

Quality control is universally recognised as fundamentally important in ensuring that diagnostic laboratories are performing appropriate tests at acceptable levels of competence. Therefore, the working group "Quality assurance--Fungi in Indoor Environments" which was initiated by the Public Health Service Baden-Württemberg (LGA BW) started with the external quality assurance in the diagnosis of indoor fungi in autumn 2001. Up to now we carried out the third mailing based on pure cultures. The results are reported and will be discussed. Exchanging experience on the international level is intended.

[Detection of airborne cultivatable microorganisms from compost sites--emissions and imissions]. / Erfassung von luftgetragenen kultivierbaren Mikroorganismen aus Kompostierungsanlagen--Emission und Immission.

The statement presented here gives an overview and assessment of the procedures and concepts currently used for the collection and determination of airborne, culturable microorganisms at sources of emission within composting plants and in their near vicinity. The paper focuses on "classical" methods, which involve cultivation as an intermediate step for the determination of viable, airborne microorganisms. The theoretical and practical requirements on such methods are discussed. Results and experiences from recent investigations are described.

Effects of hydroxyurea on the mitotic activity and the G2 phase in hairless mouse epidermis.

Hairless mice were given 5 mg hydroxyurea (HU) intraperitoneally (i.p.) followed by 0.15 mg Colcemid at various times after HU. The animals were killed at 2 and 4 hr after Colcemid, the epidermal mitotic counts in dorsal skin were determined and the mitotic rates calculated. These were compared with the normal mitotic rates, and the ratios between the results from HU-treated and -untreated animals were calculated. Hydroxyurea caused a considerable reduction in the mitotic rate with a trough at 6 hr, followed by a wave of increased mitotic rate with a peak at 14 hr, followed by a secondary drop at 20 hr, and then a return to normal. Another group of mice were given HU only, and the fraction of epidermal cells in G2 was measured by flow cytometry. From these animals, without previous injection of Colcemid, we also determined the mitotic counts and calculated the mitotic durations. Cells piled up in G2 for the first 6 hr after HU injection, then the G2 compartment was emptied. The results are discussed in relation to previous results from this department showing the effect of the same dose of HU on DNA synthesis in the same mouse strain. It is concluded that HU not only blocks or retards DNA synthesis in epidermal cells, but also affects the movement of cells through G2 and M. The cell kinetic effects of HU thus seem to be very complex.