Diurnal pollution cycle

Solar systems are subjected to a unique set of conditions that may alter their stability and, hence, their performance and life-cycle costs. These conditions include UV radiation, temperature, atmospheric gases and pollutants, the diurnal and annual thermal cycles, and, in concentrating systems, a high-intensity solar flux. In addition, condensation and evaporation of water, rain, hall, dust, wind, thermal expansion mismatches, etc., may impose additional problems for the performance of a solar system. These conditions and problems must be considered not only individually, but also for synergistic degradative effects that may result from their collective action on any part of the system. Since these degradative effects may also reduce the system or component performance, protective encapsulation of sensitive materials from the hostile terrestrial environment is required to provide component durability. 

Attempts to measure DMS in air masses influenced by polluted continental regions have yielded quite different results, with a higher degree of variability and less well defined diurnal cycles. In the North Atlantic, Andreae et al. (12) used trajectory analysis to separate their data set into air masses of continental... 

Due to the contrasting diurnal patterns of primary and secondary pollutants, ozone and other secondary pollutants appear to anticorrelate with their precursor species (NO and VOCs) if measured concentrations are plotted for a full diurnal cycle. Peak ozone occurs during and after the time of maximum sunlight, which is also the time of maximum vertical dilution. Concentrations of primary pollutants reach their diurnal minimum at this time. 

The kinetics of photochemical processes depend to a great extent on the solar radiation intensity. This also affects the production of photochemi-cally produced secondary polluting components, which varies according to the rhythm of the diurnal cycle of the solar intensity. 

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