Seasonal pollution cycle

Besides structural, compositional, morphological, and dimensional (especially thickness) sample characteristics, behavior during natural aging also depends on geographic location (latitude, altitude, mountain, sea, desert, etc.), solar radiation intensity, season, (thermal cycling), environment (indoor or outdoor hot, cold, or seawater soil type, chemicals), rain, humidity, atmospheric contamination (pollutants, smoke, fog), etc. 

In many cases, poor correlation with outdoor test results can be attributed to inadequate simulation of the SPD of the natural soin-ce. However, when using an appropriately filtered xenon arc source at an acceptable irradiance level, lack of correlation can be due to other factors that are not adequately simulated. These may be the dry/wet cycle, type of wetting, temperatiu-e and its variations, humidity conditions during exposure to the radiation source, the Ught/dark cycle, and atmospheric pollutants. For some materials, lack of a dark period can preclude correlation with natural exposures. Just as the season in which the outdoor... 

Lacustrine sediments incorporate isotopes and pollutants (Heyvaert et al. 2000). Detailed stratigraphic records develop in lakes with seasonal sedimentation patterns and little perturbation of the sediment layers. Seasonality of sedimentation patterns can be caused by seasonal throw-flow or seasonal cycles of plankton communities. 

Abstract Multicomponent materials based on synthetic polymers were designed and used in a wide variety of common and hi-tech applications, including the outdoor applications as well. Therefore, their response to the UV radiation and complex weathering conditions (temperature, seasonal or freeze—thaw cycles, humidity, pH, pollutants, ozone, microorganisms) is a matter of utmost importance in terms of operational reliability and lifetime, protection of the environment and health safety. This chapter offers an overview of this subject and a critical assessment of more particular topics related to this issue. Thus, various types of multicomponent systems based on thermoplastic and thermosetting polymer matrices were subjected to natural and/or simulated UV radiation and/or weathering conditions. Their behavior was evaluated in correlation with their complex formulation and taking into consideration that the overall effect is a sum of the individual responses and interactions between components. The nature and type of the matrix, the nature, type and size distribution of the filler, the formation of the interphase and its characteristics, the interfacial adhesion and specific interfacial interactions, they all were considered as factors that influenced the materials behavior, and, at the same time, were used as classification criteria for this review. 

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