F. De Wiest

Any factors influencing the dispersion and the transport of heavy hydrocarbons associated with airborne particles

Abstract Recent observations in Belgium indicated that particulate combustion residues are transported over large distances. The purpose of this paper is to examine in greater detail any factors — size distributions of heavy hydrocarbons, dynamic characteristics of the lowest atmosphere — influencing the advection of these pollutants.

Sur la validite des determinations du benzo (a) pyrene atmospherique pendant les mois d'ete

Abstract The influence of summer-like temperatures on losses of benzo (a) pyrene from airborne particles collected on filters has been studied during real high volume atmospheric samplings. The importance and the extreme variability of observed losses are briefly discussed. We conclude that it is necessary to develop and normalize a more adequate method to sample polycyclic hydrocarbons during hot weather.

Mutagenic activity of non-volatile organic matter associated with suspended matter in urban air

Extracts of atmospheric suspended matter showed a direct mutagenic effect in the Ames test. This effect was increased by metabolic activation. These extracts were separated into an aliphatic, an aromatic and a polar fraction. The aliphatic fraction had no effect, with or without activation; the aromatic fraction showed the greatest mutagenicity with and without activation; the polar fraction was also mutagenic, but its metabolic activation did not enhance the effect. The active compounds in this last fraction could be represented in a significant part by oxygenated derivatives of polycyclic aromatic hydrocarbons.

Determination par spectrometrie infrarouge de la matiere organique non volatile associee aux particules en suspension dans l'air—II. Facteurs influencant l'indice aliphatique

Abstract The infrared estimation of organic aliphatic material collected on glass fiber filters at commonly used air flow rates shows clearly that the composition of this material, adsorbed on suspended matter, varies greatly with the flow rate and duration of sampling: Most compounds with boiling temperatures lower than 300°C are progressively eliminated from the sample. If sampling lasts 24 h and more, the composition of the sample is thus stabilized and standardization of the spectrophotometer response against a weighed amount of extract is quite satisfactory, the nature of the remaining heavy aliphatic substances showing little variability for different places and periods of the year.

Dosage du benzo[a]pyrène atmosphérique par couplage des techniques fluorimétrique et spectrophotométrique à scintillation liquide

Abstract Estimation of atmospheric benzo[a]pyrene using fluorimetry coupled with liquid scintillation spectrometry Methods for the rapid determination of benzo[ a ]pyrene rest mainly on the separation of the substance by thin-layer chromatography, followed by its spectrophotometric or fluorimetric estimation. Published papers seldom state the recovery results. It is shown here that, with the aid of radioactive benzo[ a ]pyrene tracer and liquid scintillation spectrometry, recovery becomes poorer and less reproducible as the sample decreases in size (to less than 1 μg benzo[ a ]pyrene). Coupling fluorimetry with liquid scintillation spectrometry provides an easy means of reducing this common source of error.

Determination par spectrometrie infrarouge de la matiere organique non volatile associee aux particules en suspension dans l'air—I. Choix des conditions operatoires

Abstract The paper proposes an i.r. spectrometric method for the determination of the non volatile organic matter associated with the airborne particulates. It describes the operating conditions of the system; data concerning sensitivity and reproducibility are given. Several parameters which must be taken into account for the establishment of the calibration curve are listed.

Interfacial Physicochemical Characteristics of Airborne Soot Particles.

Abstract We describe carbon black and combustion soots surface characteristics. This description may improve our conception of one interfacial structure of airborne soot particles.

Répartition granulométrique des hydrocarbures lourds associés aux particules en suspension dans l'air de la Belgique

Abstract In order to study in more detail the possibility of transporting aerosols produced by combustion over long distances, the distribution of heavy hydrocarbons (polycyclic and paraffinic) on atmospheric particles has been studied according to their diameter. For this purpose the Anderson cascade impactor has been used. The results show that the hypothesis, that hydrocarbon aerosols are transported over long distances, is perfectly plausible and thus, that aromatic polycyclic hydrocarbons are more accurate and specific indicators than the total hydrocarbon matter.

Meteorological Episodes Increasing air Pollution in Belgium

Publisher Summary During the course of a recent survey in Belgium, it was observed that several cases of air pollution increased because of the atmospheric conditions. These are associated with cold continental anticyclonic air masses from the northeast and are observed during the coldest months of the year. They can persist for 2 to 5 consecutive days, have a maximum occurrence frequency on the order of 5%, and give rise to mean pollution levels about 3 to 3.5 times higher than those usually observed with well-ventilated maritime winds from the southwest. In the presence of some particular meteorological conditions—northeast winds strongly stabilize under the influence of an anticyclonic area—the concentrations of the primary pollutants in the ambient air exceed in Belgium most of the limit values imposed by air pollution legislation in force in the industrial countries. Thus, in practice, such legislation satisfies the jurists but not the hygienists. The only way to respect these air quality rules in highly populated and industrial areas is better control and therefore efficacious legislation concerning the emission rates in connection with the atmospheric conditions.