Atmospheric chemistry of Z- and E-CF3CH=CHCF3

The atmospheric fates of Z- and E-CF3CH=CHCF3 have been studied, investigating the kinetics and the products of the reactions of the two compounds with Cl atoms, OH radicals, OD radicals, and O3. FTIR smog chamber experiments measured: k(Cl + Z-CF3CH=CHCF3) = (2.59 ± 0.47) × 10−11, k(Cl + E-CF3CH=CHCF3) = (1.36 ± 0.27) × 10−11, k(OH + Z-CF3CH=CHCF3) = (4.21 ± 0.62) × 10−13, k(OH + E-CF3CH=CHCF3) = (1.72 ± 0.42) × 10−13, k(OD + Z-CF3CH=CHCF3) = (6.94 ± 1.25) × 10−13, k(OD + E-CF3CH=CHCF3) = (5.61 ± 0.98) × 10−13, k(O3 + Z-CF3CHCHCF3) = (6.25 ± 0.70) × 10−22, and k(O3 + E-CF3CH=CHCF3) = (4.14 ± 0.42) × 10−22 cm3 molecule−1 s−1 in 700 Torr of air/N2/O2 diluents at 296 ± 2 K. E-CF3CH=CHCF3 reacts with Cl atoms to give CF3CHClC(O)CF3 in a yield indistinguishable from 100%. Z-CF3CH=CHCF3 reacts with Cl atoms to give (95 ± 10)% CF3CHClC(O)CF3 and (7 ± 1)% E-CF3CH=CHCF3. CF3CHClC(O)CF3 reacts with Cl atoms to give the secondary product CF3C(O)Cl in a yield indistinguishable from 100%, with the observed co-products C(O)F2 and CF3O3CF3. The main atmospheric fate for Z- and E-CF3CH=CHCF3 is reaction with OH radicals. The atmospheric lifetimes of Z- and E-CF3CH=CHCF3 are estimated as 27 and 67 days, respectively. IR absorption cross sections are reported and the global warming potentials (GWPs) of Z- and E-CF3CH=CHCF3 for the 100 year time horizon are calculated to be GWP100 = 2 and 7, respectively. This study provides a comprehensive description of the atmospheric fate and impact of Z- and E-CF3CH=CHCF3

Atmospheric chemistry of isopropyl formate and tert-butyl formate

Article on the atmospheric chemistry of isopropyl formate and tert-butyl formate

United Nations Environment Programme (UNEP), Questions and Answers about the Effects of Ozone Depletion, UV Radiation, and Climate on Humans and the Environment. Supplement of the 2022 Assessment Report of the UNEP Environmental Effects Assessment Panel

This collection of Questions & Answers (Q&As) was prepared by the Environmental Effects Assessment Panel (EEAP) of the Montreal Protocol under the umbrella of the United Nations Environment Programme (UNEP). The document complements EEAP’s Quadrennial Assessment 2022 (https://ozone. unep.org/science/assessment/eeap) and provides interesting and useful information for policymakers, the general public, teachers, and scientists, written in an easy-to-understand language

United Nations Environment Programme (UNEP), Plastics in the environment in the context of UV radiation, climate change and the Montreal Protocol. 2023 Assessment Update of the UNEP Environmental Effects Assessment Panel

Solar ultraviolet radiation is a contributing factor in the environmental fate of toxic chemicals and other contaminants, with consequences that may be either beneficial or detrimental for the health of humans and the environment. This Assessment Update (2023) by the Environmental Effects Assessment Panel (EEAP) focusses on the role and significance of UV radiation and associated drivers on the breakdown of plastic waste in the environment. Plastic is a ubiquitous pollutant. UV radiation and mechanical stress drive the degradation and fragmentation of larger plastic waste into smaller micro- and nanoplastics. The Assessment Update considers the interactive effects of UV radiation and climate change on plastic durability, weathering, longevity, and ultimately the fate of plastic debris