Les niveaux de concentration des pesticides dans l’atmosphère méritent une attention particulière de la part de la recherche compte tenu de leurs impacts potentiels sur la population et les écosystèmes. L’activité agricole constitue la principale source de contamination de l’atmosphère par les pesticides. Bien que la volatilisation depuis la plante soit reconnue plus intense et plus rapide que la volatilisation depuis le sol, cette voie de transfert est à ce jour la moins bien renseignée avec peu de modèles disponibles pour sa description. Le manque de connaissances est lié essentiellement à la complexité des interactions entre les processus ayant lieu à la surface de la feuille et qui sont en compétition avec la volatilisation, notamment la pénétration foliaire et la photodégradation. Cet article présente une synthèse bibliographique sur l’état des lieux des connaissances sur le processus de volatilisation des pesticides depuis un couvert végétal, de la pénétration foliaire et de la photodégradation, ainsi que les facteurs de contrôle de ces processus. Les méthodes de mesure ainsi que les modèles existants décrivant ces processus sont également présentés et analysés | The agricultural activity presents the main source of the atmospheric contamination by pesticides. The occurrence of pesticides in the atmosphere concerns the research community due to their potential impacts on population and ecosystems. The volatilization from plants is higher and faster than the volatilization from soil. However, this transfer pathway is difficult to assess with few available models. The lack of knowledge on pesticide volatilization from plants is essentially linked to the complex interactions between processes occurring at the leaf surface and competing with volatilization, such as leaf penetration and photodegradation. This article presents a bibliographic synthesis of the state of knowledge on pesticide volatilization from plants, leaf penetration, photodegradation and control factors of these processes. Measuring methods and existing models describing these processes are also presented and analyzed

We studied magnetic and chemical parameters of sediments from sediments of a water reservoir at Linfen (China) in order to quantitatively reconstruct the atmospheric pollution history in this region. The results show that the main magnetic phases are magnetite and maghemite originating from the surrounding catchment and from anthropogenic activities, and there is a significant positive relationship between magnetic concentration parameters and heavy metals concentrations, indicating that magnetic proxies can be used to monitor the anthropogenic pollution. In order to uncover the atmospheric pollution history, we combined the known events of environmental improvement with variations of magnetic susceptibility (χ) and heavy metals along the cores to obtain a detailed chronological framework. In addition, air comprehensive pollution index (ACPI) was reconstructed from regression equation among magnetic and chemical parameters as well as atmospheric monitoring data. Based on these results, the atmospheric pollution history was successfully reconstructed.

This critical review presents several aspects related to the use of copper as a main component in brake pads in road vehicles. The compositions of these materials are attracting increasing interest and concern due to the relative contribution of wear products to particulate matter emissions in the environment as a result of braking action even though there has been a reduction in exhaust products from internal combustion engines. We review the data on the main wear mechanisms in brake systems and highlight the positive role of copper. However, similar to other heavy metal emissions, even the release of copper into the atmosphere may have important environmental and health effects. Thus, several replacement strategies are being pursued, and the positive and negative features will be critically reviewed. Additionally, the future perspectives in materials development will be discussed.

A number of studies have focused on urban trees to understand their mitigation capacity of air pollution. In this study particulate matter (PM) deposition on Quercus ilex leaves was quantitatively analyzed in four districts of the City of Terni (Italy) for three periods of the year. Fine (between 0.2 and 2.5 μm) and Large (between 2.5 and 10 μm) PM fractions were analyzed. Mean PM deposition value on Quercus ilex leaves was 20.6 μg cm−2. Variations in PM deposition correlated with distance to main roads and downwind position relatively to industrial area. Epicuticular waxes were measured and related to accumulated PM. For Fine PM deposited in waxes we observed a higher value (40% of total Fine PM) than Large PM (4% of total Large PM). Results from this study allow to increase our understanding about air pollution interactions with urban vegetation and could be hopefully taken into account when guidelines for local urban green management are realized.

Dentro de las características básicas de los modelos de dispersion de contaminantes es necesario tener en cuenta que ante todo son una representacion matematica de los diferentes procesos de transporte y difusion que se presentan en la atmosfera en un determinado tiempo y escala determinada. Estos modelos permiten simular y pronosticar las condiciones metereologicas dentro de los parametros analizados, conocer la parcialmente los procesos fisicos y/o quimicos que participan en la dispersiòn, transporte, transformacion y deposiciòn final de las contaminates en la atmosfera, lo que requiere novedos arreglos para su desarrollo y ejecuciòn. Como señalan (Ruíz & Pabón, 2002) la calidad del aire de cualquier región se obtiene mediante una serie de medidas de los niveles de inmición realizadas en una red de calidad de aire o por medio de la estimación de las diferentes concentraciones de los gases y particulas contaminantes mediante modelos que pueden ser fisicos, numericos o semiempiricos. A continuacion se analiza la posibilidad de utilizar modelos que estimen la dispersión de los contaminantes al interior de la capa limite basados en las ecuaciones de difusión-advección, discretizando N sub-intervalos al interior de la PBL, se presupone que dichas herramientas permitirán conocer la dispersión de contaminantes en las ciudades, teniendo previo conocimiento de la circulación característica, el régimen de inestabilidad, régimen radiativo y conductividad térmica del suelo; a partir de los cuales se pueden inferir los flujos de impulso, masa y energía (flujos de calor turbulento). Necesarios para determinar los movimientos verticales tanto ascendentes como descendentes necessarios para el pronostico de la contaminacion del aire. | Among the basic features of the models of dispersion of pollutants it is necessary to consider that first of all is a mathematical representation of the different transport and diffusion processes that occur in the atmosphere at a certain time and a certain scale. These models simulate and forecast meteorological conditions within the parameters analyzed, partially understand the physical processes and / or chemicals involved in the dispersion, transport, transformation and deposition of pollutants in the end the atmosphere, which requires arrangements novedos its development and implementation. As pointed out (Ruiz & Pabón, 2002) air quality of any region is obtained through a series of measures undertaken inmición levels in a network of air quality or by estimating the different concentrations of gases and particulate pollutants by models which can be physical, numerical or semiempirical. Below the ability to use models to estimate the dispersion of pollutants into the boundary layer based on the advection-diffusion equations is analyzed, discretizing N sub-intervals within the PBL, it is assumed that these tools permit the dispersion of pollutants in cities, having prior knowledge of the characteristic movement, the regime of instability, radiative thermal conductivity regime and soil; from which it can be inferred flows momentum, mass and energy (heat turbulent flows). Necessary to determine both upward and downward vertical movements necessarios for forecasting air pollution.