Halogen (chlorine, bromine, and iodine) species actively interact with other atmospheric constituents such as nitrogen oxides, organic gases, and ozone. Previous field observations confirmed the ubiquitous existence of halogens in various environments and modeling simulations quantified halogen impacts on air pollutants at present time. However, the abundance and impacts of continental inorganic halogens (CIH) on global air quality throughout history remain unexplored. Here, we present a global inventory of CIH emissions from anthropogenic and biomass-burning sources from 1970 to 2015, with average fluxes of 4302, 207, and 98 kt/yr for chlorine, bromine, and iodine, respectively, representing ~15%, 5-10%, and ~3% of the corresponding global short-lived chlorine, bromine, and iodine emissions. Incorporating these emissions into a global chemistry-climate model reveals a substantial increase ( > 50%) in inorganic halogen levels over continents, helping to reproduce the observed halogen levels. Our results also suggest substantial effects of CIH on air pollutant concentrations with significant spatio-temporal variations, e.g., the largest perturbations in nitrogen oxides and secondary aerosols migrating from Europe and North America in the 1980s-1990s, to East Asia in the 2000s, then to South Asia in the 2010s, suggesting a movement of CIH-associated air quality impact hotspots from the developed regions to the developing areas. This study highlights the under-appreciated role of halogen chemistry in air quality and its evolution in the recent four decades and calls for attention to the potential CIH impacts in emerging regions where field observations are not yet available.

One of the principal diurnal oxidation pathways of biogenic volatile organic compounds, including terpenes and their oxygenated derivatives, is the reaction with the hydroxyl radical (OH). This work presents a kinetic and product study for the reaction of OH radicals with the terpenoid (Z)-3,7-dimethylocta-2,6-dien-1-ol (nerol) in the gas phase at (298 +/- 2) K and atmospheric pressure. To our knowledge, the present study provides the first kinetic determination and product identification of the nerol + OH reaction. A conventional relative-rate technique was used to determine the rate coefficient: k(OH+nerol)= (1.6 +/- 0.2) x 10-10, in units of cm3 molecule-1s-1. The kinetic result is compared with the value estimated by the structure-reactivity relationship (SAR) method and with the experimental value reported in the literature for its isomer. In addition, the main reaction products in the gas phase and in presence of NOx (nitrogen oxides) were identified: 6-methyl-5-hepten-2-one, glycolaldehyde, acetone and formaldehyde. Under our experimental conditions, yields of 6 % and 50 % were found for formaldehyde and acetone, respectively. A general scheme of the reaction mechanism is proposed based on the identified products. Finally, an approximation of the atmospheric implications of their emission to the troposphere is discussed based on the experimental results obtained in this work.

Atmospheric oxidation largely determines the abundance and lifetime of short-lived climate forcers like methane, ozone and aerosols, as well as the removal of pollutants from the atmosphere. Hydroxyl, nitrate and chlorine radicals (OH, NO3 and Cl), together with ozone (O3), are the main atmospheric oxidants. Short-lived halogens (SLH) affect the concentrations of these oxidants, either through direct chemical reactions or indirectly by perturbing their main sources and sinks. However, the effect of SLH on the combined abundance of global oxidants during historical periods remains unquantified and is not accounted for in air quality and climate models. Here, we employ a state-of-the-art chemistry-climate model to comprehensively assess the role of SLH on atmospheric oxidation under both pre-industrial (PI) and present-day (PD) conditions. Our results show a substantial reduction in present-day atmospheric oxidation caused by the SLH-driven combined reduction in the global boundary layer levels of OH (16%), NO3 (38%) and ozone (26%), which is not compensated by the pronounced increase in Cl (2632%). These global differences in atmospheric oxidants show large spatial heterogeneity due to the variability in SLH emissions and their nonlinear chemical interactions with anthropogenic pollution. Remarkably, we find that the effect of SLH was more pronounced in the pristine PI atmosphere, where a quarter (OH: -25%) and half (NO3: -49%) of the boundary layer concentration of the main daytime and nighttime atmospheric oxidants, respectively, were controlled by SLH chemistry. The lack of inclusion of the substantial SLH-mediated reduction in global atmospheric oxidation in models may lead to significant errors in calculations of atmospheric oxidation capacity, and the concentrations and trends of short-lived climate forcers and pollutants, both historically and at present.

Reactive halogens (X + XO, X = I, Br or Cl) catalytically destroy a fraction of tropospheric ozone under present‐day (PD) conditions, however, their distribution and potential impact on tropospheric ozone under pre‐industrial (PI) conditions remain largely unexplored. This study uses the Community Atmosphere Model with Chemistry (CAM‐Chem) to investigate the effect of anthropogenically amplified natural emissions of halogenated species and their subsequent chemistry on tropospheric ozone under PI and PD atmospheric conditions. Model results show that the global tropospheric ozone depletion due to natural halogens is slightly more sensitive in PI than PD, with percentage changes in tropospheric ozone burden (TOB) of −14.1 ± 0.6% for PI and −12.9 ± 0.6% for PD. Individually, the role of iodine and chlorine in ozone depletion is equivalent in both periods (ΔTOB I : ∼−7% and ΔTOB Cl : ∼−2.5%), while bromine plays a larger role in PI (ΔTOB Br : −5.5 ± 0.6%) versus PD (ΔTOB Br : −4.3 ± 0.7%). The increase in anthropogenic ozone precursor emissions from PI to PD has amplified the natural emission of inorganic halogens and led to a shift in the partitioning of inorganic halogens from reactive to reservoir species. Consequently, halogen‐driven ozone depletion from the surface to the free troposphere is larger in PI than PD. In contrast, in the upper troposphere, the ozone depletion is larger in PD influenced mainly by stratospheric intrusion of reactive halogens from long‐lived species. This study highlights the importance of including a complete chemical coupling of natural halogens and atmospheric pollutants in chemistry‐climate models to adequately assess their effects on tropospheric ozone in a changing climate.

Halogens (I, Br and Cl) emitted from natural sources catalytically destroy a fraction of tropospheric ozone, a trace gas that plays a key role in atmospheric chemistry, both as a greenhouse gas and as a component of photochemical smog, affecting air quality and public health. Previous studies have explored the effect of halogens on ozone in present-day (PD) and future time, while the role of halogens in pre-industrial (PI) ambient conditions is quite uncertain. We use the Community Atmospheric Model with Chemistry (CAM˗Chem) to explore the effect of both natural sources and chemistry of halogens on tropospheric ozone in the PI and PD. The model results show that natural halogens have comparatively a larger impact on ozone under less polluted atmospheric conditions, with percentage changes in tropospheric ozone burden (TOB) of ˗14% for PI and ˗13% for PD. Individually, the role of iodine in ozone destruction is equivalent in both periods (ΔTOBI: ˗7%). Bromine plays a larger role in PI (ΔTOBBr: ˗5%) vs. PD (ΔTOBBr: ˗4%), while chlorine plays a larger role in PD (ΔTOBCl: ˗2.5% vs. ˗2%). The increase in anthropogenic ozone precursor emissions from PI to PD drives an enhancement in the inorganic halogen budget, as well as a change in the partitioning of inorganic halogens, shifting from reactive (X+XO, X= I, Br or Cl) to reservoirs (e.g. HOX and XONO2) species. Consequently, model results show that the halogen-mediated ozone depletion in the global lower troposphere is higher in PI than in PD. This study highlights the importance of including a complete chemical representation of natural halogens in chemistry-climate models to adequately assess their effects on tropospheric ozone in a changing climate

The degradation process of cyclobutanol (cButOH) by hydroxyl radical (OH), under atmospheric conditions, (750 & PLUSMN; 10) Torr of air and (296 & PLUSMN; 2) K, has been studied. The rate coefficient for the title reaction (k(296K) = (7.3 & PLUSMN; 0.6) x 10(-12) cm(3) molecule(-1) s(-1)) was determined at 296 K by the conventional relative-rate method. Electronic structure calculations with uCCSD(T)/uBHandHLYP/aug-cc-PVDZ were conducted to study the reaction mechanism. The global rate coefficient was also calculated using the transition state theory with tunnelling corrections, obtaining a value of 5.4 x 10(-12) cm(3) molecule(-1) s(-1) in agreement with the experimental determination. Additionally, reaction products identification in clean and NOx-contaminated atmospheres was performed for the first time. The identified reaction products and their corresponding yields (Y-P) depend on the environment composition in which the reaction is studied. In the absence of NOx, cyclobutanone (cButanone) was the only identified product, with Y-cButanone = (0.66 & PLUSMN; 0.08). In NOx-contaminated atmospheres, in addition to cButanone, tetrahydrofuran (THF), 2-nitro-1-butanol (2N1B), 3-nitro-2-butanol (3N2B) and 2-methyl-2-nitro-1propanol (2M2N1P), were also identified as primary reaction products. Under this condition, we were able to determine only the yields of cButanone and THF (Y-cButanone = 0.38 & PLUSMN; 0.05 and Y-THF = 0.28 & PLUSMN; 0.02). A likely reaction mechanism for the observed products is proposed and the atmospheric implications are discussed.

In the framework of the SouthTRAC Campaign (Transport and Composition of the Southern Hemisphere Upper Troposphere and Lower Stratosphere) based on Rio Grande, Argentina, a local research group from CONICET (Argentine National Research Council) joined the German consortium maintaining the HALO research aircraft (High-Altitude and LOng-range aircraft) to help with the flight planning and evaluation of the chemical composition of the upper troposphere and lower stratosphere within the ozone hole periphery. The SouthTRAC aircraft campaign was carried out in two phases which took place in September and November 2019, respectively. With the purpose of providing additional information of the atmospheric composition of brominated Very Short-Lived (VSLBr) species and compare with HALO observations during the transfer and campaign flights, a CAM-Chem (Community Atmosphere Model with Chemistry) global chemistry-climate simulation was conducted. The model setup used in the halogenated CAM-Chem simulation had a 1° x 1.25° lat-lon resolution, 56 hybrid vertical levels from the surface to the middle stratosphere and considered assimilated meteorology from MERRA, including an explicit treatment of VSLBr sources and chemistry. Model output of VSLBr, long-lived bromine and chlorine (LLBr and LLCl) species and ozone mixing ratios, as well as the main inorganic halogen reactive and reservoir species and gas/heterogeneous phase reaction rates affecting lowermost stratospheric ozone were analyzed in horizontal domains and vertical cross-sections across each flightpath. The model performance with respect to the HALO observations has a general good agreement, presenting better results for mid latitudes (between 30º S and 50º S) than for southern latitudes (>50º S). In particular, CAM-Chem timeseries consistently reproduced the spatio-temporal variation of the main VSLBr species (CH2Br2 and CHBr3), including the sharp variations observed across the tropopause. For both VSLBr as well as for LLCl compounds such as CFC-12, the Pearson correlation coefficient r obtained during each of the flights ranged between 0.7 and 0.9, while the Normalized Mean Bias (NMB) was smaller than 8% for almost every flight. Regarding LLBr CH3Br, the correlation with the aircraft observations is high (r>0.9) but the inter-hemispheric variability during transfer flights is not fully captured. For Ozone, the model presents mid to high correlation with respect to measures (0.5

Biogenic very short-lived bromocarbons (VSLBr) currently represent ∼25 % of the total stratospheric bromine loading. Owing to their much shorter lifetime compared to anthropogenic long-lived bromine (e.g. halons) and chlorine (e.g. chlorofluorocarbons), the impact of VSLBr on ozone peaks in the lowermost stratosphere, which is a key climatic and radiative atmospheric region. Here we present a modelling study of the evolution of stratospheric ozone and its chemical loss within the tropics and at mid-latitudes during the 21st century. Two different experiments are explored: considering and neglecting the additional stratospheric injection of 5 ppt biogenic bromine naturally released from the ocean. Our analysis shows that the inclusion of VSLBr results in a realistic stratospheric bromine loading and improves the agreement between the model and satellite observations of the total ozone column (TOC) for the 1980–2015 period at mid-latitudes. We show that the overall ozone response to VSLBr at mid-latitudes follows the stratospheric evolution of long-lived inorganic chlorine and bromine throughout the 21st century. Moreover, the seasonal VSLBr impact on lowermost stratospheric ozone at mid-latitude is influenced by the seasonality of the heterogeneous inorganic-chlorine reactivation processes on ice crystals. Indeed, due to the more efficient reactivation of chlorine reservoirs (mainly ClONO2 and HCl) within the colder SH-ML lowermost stratosphere, the seasonal VSLBr impact shows a small but persistent hemispheric asymmetry through the whole modelled period. We conclude that the link between biogenic bromine sources and seasonal changes in heterogeneous chlorine reactivation is a key feature for future projections of mid-latitude lowermost stratospheric ozone during the 21st century.

Many Chemistry Climate Models (CCMs) include a simplified treatment of brominated very short-lived (VSLBr) species by assuming long-lived methyl bromide (CH3Br) as a surrogate for VSLBr. However, given that VSLBr (i.e., bromoform CHBr3 and dibromomethane CH2Br2) decompose more rapidly than CH3Br, their impact on upper tropospheric chemistry and lowermost stratospheric ozone cannot be neglected. Thus, a mistreatment of VSLBr in CCMs may yield an unrealistic representation of their associated impacts. Here, we present a comprehensive intercomparison between various VSLBr chemical approaches with increasing degrees of complexity (i.e., surrogate, explicit, and full), and quantify the global impacts of these natural bromocarbons on tropospheric and stratospheric ozone, as well as on other oxidizing agents. Differences between chemical schemes maximize in the lowermost stratosphere and mid-latitude free troposphere, resulting in a latitudinally dependent reduction of ~1−7 DU in total ozone column and a ~5−15 % decrease of the OH/HO2 ratio, for full compared to surrogate. These bromine-driven changes in HOx abundances are expected to slow-down the oxidative processing of greenhouse gases (i.e., to increase the CH4 lifetime) in a region where these long-lived species have a final chance to undergo tropospheric degradation before injection to the stratosphere. Given the negligible additional computational cost and chemical complexity, we encourage all CCMs oriented to projecting the coupled evolution of stratospheric ozone within a changing climate to include a complete tropospheric representation of VSLBr sources and chemistry in the troposphere and stratosphere.

Biogenic very short-lived bromocarbons (VSLBr) currently represent ∼25 % of the total stratospheric bromine loading. Owing to their much shorter lifetime compared to anthropogenic long-lived bromine (e.g. halons) and chlorine (e.g. chlorofluorocarbons), the impact of VSLBr on ozone peaks in the lowermost stratosphere, which is a key climatic and radiative atmospheric region. Here we present a modelling study of the evolution of stratospheric ozone and its chemical loss within the tropics and at mid-latitudes during the 21st century. Two different experiments are explored: considering and neglecting the additional stratospheric injection of 5 ppt biogenic bromine naturally released from the ocean. Our analysis shows that the inclusion of VSLBr results in a realistic stratospheric bromine loading and improves the agreement between the model and satellite observations of the total ozone column (TOC) for the 1980–2015 period at mid-latitudes. We show that the overall ozone response to VSLBr at mid-latitudes follows the stratospheric evolution of long-lived inorganic chlorine and bromine throughout the 21st century. Moreover, the seasonal VSLBr impact on lowermost stratospheric ozone at mid-latitude is influenced by the seasonality of the heterogeneous inorganic-chlorine reactivation processes on ice crystals. Indeed, due to the more efficient reactivation of chlorine reservoirs (mainly ClONO2 and HCl) within the colder SH-ML lowermost stratosphere, the seasonal VSLBr impact shows a small but persistent hemispheric asymmetry through the whole modelled period. We conclude that the link between biogenic bromine sources and seasonal changes in heterogeneous chlorine reactivation is a key feature for future projections of mid-latitude lowermost stratospheric ozone during the 21st century.

EGU General Assembly 2019,Vienna, Austria, 7–12 April 2019. -- https://www.geophysical-research-abstracts.net/egu2019.html. -- Conferencia invitada

In this work, we investigate the degradation process of 1-chlorobutane, initiated by OH radicals, under atmospheric conditions (air pressure of 750 Torr and 296 K) from both experimental and theoretical approaches. In the first one, a relative kinetic method was used to obtain the rate coefficient for this reaction, while the products were identified for the first time (1-chloro-2-butanone, 1-chloro-2-butanol, 4-chloro-2-butanone, 3-hydroxy-butanaldehyde, and 3-chloro-2-butanol) using mass spectrometry, allowing suggesting a reaction mechanism. The theoretical calculations, for the reactive process, were computed using the BHandHLYP/6-311++G(d,p) level of theory, and the energies for all of the stationary points were refined at the CCSD(T) level. Five conformers for 1-chlorobutane and 33 reactive channels with OH radicals were found, which were considered to calculate the thermal rate coefficient (as the sum of the site-specific rate coefficients using canonical transition state theory). The theoretical rate coefficient (1.8 × 10-12 cm3 molecule-1 s-1) is in good agreement with the experimental value (2.22 ± 0.50) × 10-12 cm3 molecule-1 s-1 determined in this work. Finally, environmental impact indexes were calculated and a discussion on the atmospheric implications due to the emissions of this compound into the troposphere was given.

The rate coefficients for the reactions of OH radicals and Cl atoms with 3-methoxy-1-propanol (3-M-1-POL) and 3-methoxy-l-butanol (3-M-1-BOL) in the gas-phase have been measured at (298 +/- 2) K and atmospheric pressure. A conventional relative-rate technique was used to determine the rate coefficients: k(1) (OH + 3-M-1-POL) = (2.15 +/- 0.28) x 10(-11), k(2) (OH + 3-M-1-BOL) = (2.38 +/- 0.31) x 10(-11), k(3) (Cl + 3-M-1-POL) = (2.66 +/- 0.23) x 10(-10) and k(4) (Cl + 3-M-1-BOL) = (2.95 +/- 0.27) x 10(-10), all in units of cm(3) molecule(-1)s(-1). The present work provides the first kinetic study of the reactions of Cl atoms with 3-M-1-POL and 3-M-1-BOL, and of the reaction of OH radicals with 3-M-1-POL. The kinetic results are presented and compared with those calculated (k(SAR)) using the structure-reactivity relationship (SAR) method, and reactivity trends are discussed. Additionally, products identification under atmospheric conditions was performed for the first time for the reactions cited above in the presence of NO, using two sampling methods and GC-MS-FID. 3-methoxypropanal, methyl formate and glycolaldehyde were identified from the 3-M-1-POL + OH/Cl reactions, while 3-methoxybutyraldehyde, methyl acetate and glycolaldehyde, were identified from the 3-M-1-BOL + OH/Cl reactions. From these identified products, a general scheme of the reaction mechanisms is proposed. Finally, based on the kinetic results and radiative efficiencies (REs) of the titled compounds, a discussion on the atmospheric implications due to its emissions into the troposphere is also presented.

Abstract Current chemistry climate models do not include polar emissions and chemistry of halogens. This work presents the first implementation of an interactive polar module into the very short‐lived (VSL) halogen version of the Community Atmosphere Model with Chemistry (CAM‐Chem) model. The polar module includes photochemical release of molecular bromine, chlorine, and interhalogens from the sea‐ice surface, and brine diffusion of iodine biologically produced underneath and within porous sea‐ice. It also includes heterogeneous recycling of inorganic halogen reservoirs deposited over fresh sea‐ice surfaces and snow‐covered regions. The polar emission of chlorine, bromine, and iodine reach approximately 32, 250, and 39 Gg/year for Antarctica and 33, 271, and 4 Gg/year for the Arctic, respectively, with a marked seasonal cycle mainly driven by sunlight and sea‐ice coverage. Model results are validated against polar boundary layer measurements of ClO, BrO, and IO, and satellite BrO and IO columns. This validation includes satellite observations of IO over inner Antarctica for which an iodine “leapfrog” mechanism is proposed to transport active iodine from coastal source regions to the interior of the continent. The modeled chlorine and bromine polar sources represent up to 45% and 80% of the global biogenic VSLCl and VSLBr emissions, respectively, while the Antarctic sea‐ice iodine flux is ~10 times larger than that from the Southern Ocean. We present the first estimate of the contribution of polar halogen emissions to the global tropospheric halogen budget. CAM‐Chem includes now a complete representation of halogen sources and chemistry from pole‐to‐pole and from the Earth's surface up to the stratopause.

Rate coefficients for the gas-phase reactions of OH radicals and Cl atoms with 1-methoxy-2-propanone (1-M-2-PONE), 1-methoxy-2-propanol (1-M-2-POL), and 1-methoxy-2-butanol (1-M-2-BOL) were determined at room temperature and atmospheric pressure using a conventional relative-rate technique. The following absolute rate coefficients were derived: k 1(OH + 1-M-2-PONE) = (0.64 ± 0.13) × 10−11, k 2(OH + 1-M-2-BOL) = (2.19 ± 0.23) × 10−11, k 3(Cl + 1-M-2-PONE = (1.07 ± 0.24) × 10−10, k 4(Cl + 1-M-2-POL) = (2.28 ± 0.21) × 10−10, and k 5 (Cl + 1-M-2-BOL) = (2.79 ± 0.23) × 10−10, in units of cm3 molecule−1 s−1. This is the first experimental determination of k 2-k 5. These rate coefficients were used to discuss the influence of the structure on the reactivity of the studied polyfunctional organic compounds. The atmospheric implications for 1-M-2-PONE, 1-M-2-POL, and 1-M-2-BOL and their reactions were investigated estimating atmospheric parameters such as lifetimes, global warming potentials, and average photochemical ozone production. The approximate nature of these values was stressed considering that the studied oxygenated volatile organic compounds are short-lived compounds for which the calculated parameters may vary depending on chemical composition, location, and season at the emission points.

The rate coefficient of the cis-3-hexene + Cl atoms reaction at 296 ± 2 K and 750 ± 10 Torr was determined using the relative rate technique.The reaction was investigated using an 80 L Teflon reaction bag and a gas chromatograph coupled with flame-ionization detection.Chlorine atoms were produced by the photolysis of trichloroacetyl chloride.No previous experimental data was available in the literature, to the best of our knowledge.The mean second-order rate coefficient value found was (4.13 ± 0.51) × 10 -10 cm 3 molecule -1 s -1 .The experimental value agrees with the rate coefficient estimated by structure-reactivity analysis, 4.27 × 10 -10 cm 3 molecule -1 s -1 .Moreover, both addition and hydrogen abstraction channels contribute to the global kinetics, with branching ratios 70:30.Effective lifetime with respect to Cl atoms is predicted as 67.2 hours; however, the cis-3-hexene + Cl channel is suggested to be non-negligible at atmospheric conditions.Other atmospheric implications are discussed.

First relative kinetic study for the OH/Cl reactions with three chloro-fluoro-ethenes at room-temperature and atmospheric pressure and environmental acceptability.

The kinetics of the cis-3-hexene + OH reaction were investigated by an experimental relative rate method and at the density functional theory level. The experimental set-up consisted of a 200 L Teflon bag, operated at atmospheric pressure and 298 K. OH radicals were produced by the photolysis of H2O2 at 254 nm. Relative rate coefficients were determined by comparing the decays of the cis-3-hexene and reference compounds (cyclohexene, 2-buten-1-ol and allyl ether). The mean second-order rate coefficient value found was (6.27 ± 0.66) × 10(-11) cm(3) molecule(-1) s(-1), the uncertainty being estimated by propagation of errors. Theoretical calculations for the addition reaction of OH to cis-3-hexene have also been performed, at the BHandHLYP/aug-cc-pVDZ level, in order to investigate the reaction mechanism, to clarify the experimental observations and to model the reaction kinetics. Different conformations of the reactants, pre-barrier complexes and saddle points were considered in our calculations. The individual rate coefficients, calculated for each conformer of the reactant, at 298 K, using a microcanonical variational transition state method, are 4.19 × 10(-11) and 1.23 × 10(-10) cm(3) molecule(-1) s(-1). The global rate coefficient was estimated from the Boltzmann distribution of the conformers to be 8.10 × 10(-11) cm(3) molecule(-1) s(-1), which is in agreement with the experimental value. Rate coefficients calculated over the temperature range from 200-500 K are also given. Our results suggest that the complex mechanism, explicitly considering different conformations for the stationary points, must be taken into account for a proper description of the reaction kinetics.

The relative rate technique was used to determine the rate coefficients of the reactions of OH radicals with (Z)-2-hexen-1-ol (k(1)), and (E)-3-hexen-1-ol (k(2)), at (296 +/- 2) K and (750 +/- 10) Torr of N-2 or pure air. The reactions were investigated using a 200 L Teflon reaction chamber and a gas chromatograph coupled with flame-ionization detection. The following rate coefficients were derived, in units of cm(3) mol(-1) s(-1): k(1) = (1.1 +/- 0.4) x 10(-10) and k(2) = (0.8 +/- 0.1) x 10(-10). This is the first experimental determination of k(1) and k(2). A comparison between the experimental rate coefficients (kexp) and the calculated rate coefficients using the structure-activity relationship (SAR) method (k(SAR)), for the reaction of different unsaturated alcohols with OH radicals is presented. The atmospheric lifetimes of the studied alcohols were estimated considering the rate coefficients of their reactions with OH and NO3 radicals. The radiative efficiencies (REs) were obtained from the infrared spectra of the two hexenols and the global warming potentials (GWPs) were then estimated. Atmospheric implications of the alcohols emission are briefly discussed. (C) 2013 Elsevier Ltd. All rights reserved.