This paper is part of an extensive study of secondary school students' preconceived ideas about climate change. Here, we undertake a survey in the province of Valencia (Spain) to ascertain secondary school students' notions of the causes and consequences of climate change. Results show, among other things, that students clearly relate the misuse of motor vehicles and factory emissions to the problem. However, the obvious correlation with household energy use is not observed. The usual confusion with other environmental problems, such as the hole in the ozone layer, as described in previous studies, is also detected. Students know almost no greenhouse gases other than CO 2 , while the socio-economic consequences of climate change are the least perceived.

The reaction between the OH radical and glycolaldehyde has been theoretically studied for the first time. By means of preliminary MP2(FC)/6-31G*, B3LYP/6-31G*, CBS-Q, G2, and G3 electronic structure calculations, two main processes have been determined, CH2OHCHO + OH → CH2OHCO + H2O and CH2OHCHO + OH → CHOHCHO + H2O, in clear agreement with experimental data. Then the variational transition-state theory rate constants with multidimensional tunneling corrections (when necessary) (VTST-MT) have been calculated using dual-level interpolation algorithms. The theoretical rate constant for the global process at 298 K of 3.83 × 10-11 cm3 molecule-1 s-1 is in reasonable agreement with the experimental value. In the temperature range 100−350 K, we predict a clear inverse dependence of the global rate constant on temperature.

High-level electronic structure calculations were carried out for the study of the reaction pathways in the OH-initiated oxidations of methyl vinyl ketone (MVK) and methacrolein (MACR). For the two conformers of MVK (called synperiplanar and antiperiplanar), the addition channels of OH to the terminal and central carbon atom of the double bond dominate the overall rate constant, whereas the abstraction of the methyl hydrogen atoms has no significant kinetic role. In the case of MACR, only the antiperiplanar conformer is important in its reactivity. In addition, the lower Gibbs free energy barrier for MACR corresponds to the aldehydic hydrogen abstraction reaction, which will be somewhat more favorable than the addition processes. The subtle balance between the different pathways (additions versus abstractions) serves to give an understanding of the pressure dependence of the rate constants of these tropospheric oxidation processes.

High-level electronic structure calculations and master equation analyses were carried out to obtain the pressure- and temperature-dependent rate constants of the methyl vinyl ketone+OH and methacrolein+OH reactions. The balance between the OH addition reactions at the high-pressure limit, the OH addition reactions in the fall-off region, and the pressure-independent hydrogen abstractions involved in these multiwell and multichannel systems, has been shown to be crucial to understand the pressure and temperature dependence of each global reaction. In particular, the fall-off region of the OH addition reactions contributes to the inverse temperature dependence of the rate constants in the Arrhenius plots, leading to pressure-dependent negative activation energies. The pressure dependence of the methyl vinyl ketone+OH reaction is clearly more important than in the case of the methacrolein+OH reaction owing to the weight of the hydrogen abstraction process in this second system. Comparison of the theoretical rate constants and the experimental measurements shows quite good agreement.

No abstract