Pilot study of personal, indoor and outdoor exposure to benzene, formaldehyde and acetaldehyde

There is a lack of data for health risk assessment of long term personal exposure to certain ubiquitous air pollutants present particularly in urban atmospheres. The relationship between ambient background concentrations and personal exposure is often unknown. A pilot campaign to measure indoor concentrations, outdoor concentrations and personal exposure to benzene, formaldehyde and acetaldehyde was conducted in a medium sized French town. A strong contribution to total personal exposure was observed from indoor sources, especially for formaldehyde and acetaldehyde, suggesting that indoor sources are dominant for these compounds. For benzene, the average personal exposure exceeded a 10 μgm^?3 limit value, although this was not the case for the ambient background concentration. For formaldehyde, the limit level was also exceeded. Observations suggest that true personal exposure cannot be determined directly from measurements pertaining from fixed ambient background monitoring stations. It is hoped that this will be taken into consideration by the bodies responsible for monitoring air pollution and the future European Air Quality Directive.     

Die innere Struktur von Proton und Neutron

The Science of Nature -     

Thermal degradation products of spruce needles

Spruce needles are analysed by in-source pyrolysis (Py)-field ionization (FI) mass spectrography and Curie-point Py-gas chromatography/electron ionization mass spectrometry. The identified thermal degradation products allow the interpretation of the FI mass signals. It could be shown that Py-FI mass spectra of plant materials are representative fingerprints which consist primarily of molecular ions of Py products derived from the thermal degradation of the main constituents of spruce needles such as carbohydrates, lignin, lipids and proteins. Primary building blocks of these biopolymers form characteristic Py products of spruce needles. Furthermore, over 500 different molecular ion species of volatilized, thermostable plant constituents are recorded using FI as soft ionization method. The present study shows that Py-FIMS is suitable for the rapid and comprehensive characterization of complex biological materials, without pretreatment of the sample except of drying and milling. The presented results contribute to the basic knowledge for the evaluation of the causes of the present tree damage.