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Atmospheric Environment (v.43, #27)

Editorial board (pp. i).

The impacts of reactive terpene emissions from plants on air quality in Las Vegas, Nevada by Maria R. Papiez; Mark J. Potosnak; Wendy S. Goliff; Alex B. Guenther; Sou N. Matsunaga; William R. Stockwell (pp. 4109-4123).

A three-part study was conducted to quantify the impact of landscaped vegetation on air quality in a rapidly expanding urban area in the arid southeastern United States. The study combines in situ, plant-level measurements, a spatial emissions inventory, and a photochemical box model. Maximum plant-level basal emission rates were moderate: 18.1 μgC gdw⁻¹ h⁻¹ ( Washingtonia spp., palms) for isoprene and 9.56 μgC gdw⁻¹ h⁻¹ ( Fraxinus velutina, Arizona ash) for monoterpenes. Sesquiterpene emission rates were low for plant species selected in this study, with no measurement exceeding 0.1 μgC gdw⁻¹ h⁻¹. The high ambient temperatures combined with moderate plant-level emission factors resulted in landscape emission factors that were low (250–640 μgC m⁻² h⁻¹) compared to more mesic environments (e.g., the southeastern United States). The Regional Atmospheric Chemistry Mechanism (RACM) was modified to include a new reaction pathway for ocimene. Using measured concentrations of anthropogenic hydrocarbons and other reactive air pollutants (NO _x, ozone), the box model employing the RACM mechanism revealed that these modest emissions could have a significant impact on air quality. For a suburban location that was downwind of the urban core (high NO _x; low anthropogenic hydrocarbons), biogenic terpenes increased time-dependent ozone production rates by a factor of 50. Our study demonstrates that low-biomass density landscapes emit sufficient biogenic terpenes to have a significant impact on regional air quality.

Keywords: Isoprene; Monoterpene; Sesquiterpene; Biogenic volatile organic compounds (BVOCs); Emission inventory; Emission factor

The impact of nudging coefficient for the initialization on the atmospheric flow field and the photochemical ozone concentration of Seoul, Korea by Hyun-Jung Choi; Hwa Woon Lee; Kyoung-Hee Sung; Min-Jung Kim; Yoo-Keun Kim; Woo-Sik Jung (pp. 4124-4136).

In order to incorporate correctly the large or local scale circulation in the model, a nudging term is introduced into the equation of motion. Nudging effects should be included properly in the model to reduce the uncertainties and improve the air flow field. To improve the meteorological components, the nudging coefficient should perform the adequate influence on complex area for the model initialization technique which related to data reliability and error suppression. Several numerical experiments have been undertaken in order to evaluate the effects on air quality modeling by comparing the performance of the meteorological result with variable nudging coefficient experiment. All experiments are calculated by the upper wind conditions (synoptic or asynoptic condition), respectively. Consequently, it is important to examine the model response to nudging effect of wind and mass information. The MM5–CMAQ model was used to assess the ozone differences in each case, during the episode day in Seoul, Korea and we revealed that there were large differences in the ozone concentration for each run.These results suggest that for the appropriate simulation of large or small-scale circulations, nudging considering the synoptic and asynoptic nudging coefficient does have a clear advantage over dynamic initialization, so appropriate limitation of these nudging coefficient values on its upper wind conditions is necessary before making an assessment. The statistical verifications showed that adequate nudging coefficient for both wind and temperature data throughout the model had a consistently positive impact on the atmospheric and air quality field. On the case dominated by large-scale circulation, a large nudging coefficient shows a minor improvement in the atmospheric and air quality field. However, when small-scale convection is present, the large nudging coefficient produces consistent improvement in the atmospheric and air quality field.

Keywords: Nudging coefficient; Upper wind conditions; Site coherence analysis; MM5; CMAQ

A numerical experiment of roadside diffusion under traffic-produced flow and turbulence by Hiroaki Kondo; Takayuki Tomizuka (pp. 4137-4147).

Roadside air pollution due to heavy traffic is one of the unsettled issues in the atmospheric environment in urban areas. As a practical application of a Computational Fluid Dynamics (CFD) model, a coupled mesoscale-CFD model was applied to the Ikegamicho area of Kawasaki City, Japan. For this study, the effects of traffic-produced flow and turbulence (TPFT) on the dispersion of the pollutants near the heavy traffic road were mainly investigated in an actual urban area. First, a series of preliminary CFD calculations was conducted for a road tunnel field experiment to obtain a fitting parameter for the traffic-produced flow. The calculation was then performed for 24 h in December 2005 around Ikegamicho, and the results were compared with the data at a roadside monitoring post in the area, located 10 m from the boundary of the ground road. In general, the effect of traffic-produced flow and turbulence was limited at the downstream side of the roads. The maximum concentration of NO _x was reduced and smoothed out along the traffic flow by the traffic-produced flow and turbulence on the road. The effects of traffic-produced turbulence on the dispersion of pollutants were greater than those of traffic-produced flow; however, the effects of traffic-produced flow were not negligible. The concentration of pollutants was not particularly dependent on the turbulent Schmidt number because most of the emission sources were introduced as volume sources in the present calculations, and the effect caused by differences in the material diffusion coefficient was not particularly significant at the outside of the road.

Keywords: Coupled mesoscale-CFD model; Pollutant dispersion near a road; Traffic-produced flow in a road tunnel; Turbulent Schmidt number in an urban area; Two-layer road

Characteristics of gaseous pollutants from biofuel-stoves in rural China by Shuxiao Wang; Wei Wei; Li Du; Guanghui Li; Jiming Hao (pp. 4148-4154).

The research team analyzed the emission characteristics of gaseous pollutants, including volatile organic compounds (VOCs), from biomass combustion in improved stoves in rural China. The research included measurements from five biofuels and two stove types in the months of January, April, and September. The measurements were conducted according to U.S. EPA Method 25 using a collection system with a cooling device and two-level filters. CO, CO₂, NO_x, CH₄ and THC analyzers were used for in-field, real-time emission measurements. The emission data indicate that gaseous pollutants were emitted at higher concentrations in the early combustion stage and lower concentrations in the later stage. CH₄ and THC, as well as CO and CO₂, presented positive relationships during the whole entire combustion process for all tests. The chemical profiles of flue gas samples were analyzed by GC/MS and GC/FID/ECD. Aromatics, carbonyls, and alkenes & alkynes dominated the VOC emissions, respectively accounting for 37%, 33%, and 23% of total VOC emissions by volume. Benzene was the most abundant VOC species, consisting of 17.3 ± 8.1% of VOCs, followed by propylene (11.3 ± 3.5%), acetone (10.8 ± 8.2%), toluene (7.3 ± 5.7%) and acetaldehyde (6.5 ± 7.3%). Carbon mass balance approach was applied to calculate CO, CO₂, CH₄, NO_x, and VOC species emission factors. This analysis includes a discussion of the differences among VOC emission factors of different biofuel-stove combinations.

Keywords: VOC; Emission; Speciation; Biofuel

Concentrations and sources of carbonaceous aerosol in the atmosphere of Summit, Greenland by Erika von Schneidemesser; James J. Schauer; Gayle S.W. Hagler; Michael H. Bergin (pp. 4155-4162).

High-volume PM_2.5 samples were collected at Summit, Greenland for approximately six months from late May through December of 2006. Filters were composited and analyzed for source tracer compounds. The individual organic compounds measured at Summit are orders of magnitude smaller than concentrations measured at other sites, including locations representative of remote oceanic, and remote and urban continental aerosol. The measured tracers were used to quantify the contribution of biomass burning (0.6–0.9 ng C m⁻³), vegetative detritus (0.3–0.9 ng C m⁻³), and fossil fuel combustion (0.1–0.8 ng C m⁻³) sources, 4% of OC total, to atmospheric organic carbon concentrations at the remote location of Summit, Greenland. The unapportioned organic carbon (96%) during the early summer period correlates well with the fraction of water soluble organic carbon, indicating secondary organic aerosol as a large source of organic carbon, supported by the active photochemistry occurring at Summit. To the author's knowledge, this paper represents the first source apportionment results for the polar free troposphere.

Keywords: Organic aerosol; Source apportionment; Greenland

Mechanism of OH-initiated atmospheric photooxidation of the organophosphorus insecticide (C₂H₅O)₃PS by Qin Zhou; Xiangyan Shi; Fei Xu; Qingzhu Zhang; Maoxia He; Wenxing Wang (pp. 4163-4170).

O, O, O-triethyl phosphorothioate ((C₂H₅O)₃PS, TEPT) is a widely used organophosphorus insecticide. TEPT may be released into the atmosphere where it can undergo transport and chemical transformations, which include reactions with OH radicals, NO₃ radicals and O₃. The mechanism of the atmospheric reactions of TEPT has not been fully understood due to the short-lifetime of its oxidized radical intermediates, and the extreme difficulty in detection of these species experimentally. In this work, we carried out molecular orbital theory calculations for the OH radical-initiated atmospheric photooxidation of TEPT. The profile of the potential energy surface was constructed, and the possible channels involved in the reaction are discussed. The theoretical study shows that OH addition to the PS bond and H abstractions from the CH₃CH₂O moiety are energetically favorable reaction pathways. The dominant products TEP and SO₂ arise from the secondary reactions, the reactions of OH-TEPT adducts with O₂. The experimentally uncertain dominant product with molecular weight 170 is mostly due to (C₂H₅O)₂P(S)OH and not (C₂H₅O)₂P(O)SH.

Keywords: TEPT; OH radicals; Atmospheric photooxidation; Reaction mechanism; Quantum chemical study

Organic carbon, total nitrogen, and water-soluble ions in clouds from a tropical montane cloud forest in Puerto Rico by Gabriel J. Reyes-Rodríguez; Adriana Gioda; Olga L. Mayol-Bracero; Jeff Collett Jr. (pp. 4171-4177).

Chemical characterization to determine the organic and nitrogen fractions was performed on cloud water samples collected in a mountaintop site in Puerto Rico. Cloud water samples showed average concentrations of 1.09 mg L⁻¹ of total organic carbon (TOC), of 0.85 mg L⁻¹ for dissolved organic carbon (DOC) and of and 1.25 mg L⁻¹ for total nitrogen (TN). Concentrations of organic nitrogen (ON) changed with the origin of the air mass. Changes in their concentrations were observed during periods under the influence of African dust (AD). The ON/TN ratios were 0.26 for the clean and 0.35 for the AD periods. Average concentrations of all these species were similar to those found in remote environments with no anthropogenic contribution. In the AD period, for cloud water the concentrations of TOC were 4 times higher and TN were 3 times higher than during periods of clean air masses associated with the trade winds. These results suggest that a significant fraction of TOC and TN in cloud and rainwater is associated to airborne particulate matter present in dust. Functional groups were identified using proton nuclear magnetic resonance (¹H NMR) spectroscopy. This characterization led to the conclusion that water-soluble organic compounds in these samples are mainly aliphatic oxygenated compounds, with a small amount of aromatics. The ion chromatography results showed that the ionic species were predominantly of marine origin, for air masses with and without African dust influence, with cloud water concentrations of NO₃⁻ and NH₄⁺ much lower than from polluted areas in the US. An increase of such species as SO₄²⁻, Cl⁻, Mg²⁺, K⁺ and Ca²⁺ was seen when air masses originated from northwest Africa. The changes in the chemical composition and physical properties of clouds associated with these different types of aerosol particles could affect on cloud formation and processes.

Keywords: African dust; Total organic carbon; Dissolved organic carbon; Total nitrogen; Proton nuclear magnetic resonance (; ¹; H NMR) spectroscopy; Ion chromatography

Controls on hourly variations in urban background air pollutant concentrations by Teresa Moreno; Javier Lavín; Xavier Querol; Andrés Alastuey; Mar Viana; Wes Gibbons (pp. 4178-4186).

Average 21st century concentrations of urban air pollutants linked to cardiorespiratory disease are not declining, and commonly exceed legal limits. Even below such limits, health effects are being observed and may be related to transient daytime peaks in pollutant concentrations. With this in mind, we analyse >52,000 hourly urban background readings of PM₁₀ and pollutant gases throughout 2007 at a European town with legal annual average concentrations of common pollutants, but with a documented air pollution-related cardiorespiratory health problem, and demonstrate the hourly variations in PM₁₀, SO₂, NO_x, CO and O₃. Back-trajectory analysis was applied to track the arrival of exotic PM₁₀ intrusions, the main controls on air pollutants were identified, and the typical hourly pattern on ambient concentrations during 2007 was profiled. Emphasis was placed on “worst case” data (>90th percentile), when health effects are likely to be greatest. The data show marked daytime variations in pollutants result from rush-hour traffic-related pollution spikes, midday industrial SO₂ maxima, and afternoon O₃ peaks. African dust intrusions enhance PM₁₀ levels at whatever hour, whereas European PM incursions produce pronounced evening peaks due to their transport direction (across an industrial traffic corridor). Transient peak profiling moves us closer to the reality of personal outdoor exposure to inhalable pollutants in a given urban area. We argue that such an approach to monitoring data potentially offers more to air pollution health effect studies than using only 24 h or annual averages.

Keywords: Urban air pollution; Transient concentration peaks; Cardiorespiratory health effects

Characterization of PM_2.5-bound polycyclic aromatic hydrocarbons in Atlanta—Seasonal variations at urban, suburban, and rural ambient air monitoring sites by Zheng Li; Erin N. Porter; Andreas Sjödin; Larry L. Needham; Sangil Lee; Armistead G. Russell; James A. Mulholland (pp. 4187-4193).

Twenty-eight polycyclic aromatic hydrocarbons (PAH) and methylated PAHs (Me-PAH) were measured in daily PM_2.5 samples collected at an urban site, a suburban site, and a rural site in and near Atlanta during 2004 (5 samples/month/site). The suburban site, located near a major highway, had higher PM_2.5-bound PAH concentrations than did the urban site, and the rural site had the lowest PAH levels. Monthly variations are described for concentrations of total PAHs (∑PAHs) and individual PAHs. PAH concentrations were much higher in cold months than in warm months, with average monthly ∑PAH concentrations at the urban and suburban-highway monitoring sites ranging from 2.12 to 6.85 ng m⁻³ during January–February and November–December 2004, compared to 0.38–0.98 ng m⁻³ during May–September 2004. ∑PAH concentrations were found to be well correlated with PM_2.5 and organic carbon (OC) within seasons, and the fractions of PAHs in PM_2.5 and OC were higher in winter than in summer. Methyl phenanthrenes were present at higher levels than their un-substituted homologue (phenanthrene), suggesting a petrogenic (unburned petroleum products) input. Retene, a proposed tracer for biomass burning, peaked in March, the month with the highest acreage and frequency of prescribed burning and unplanned fires, and in December, during the high residential wood-burning season, indicating that retene might be a good marker for burning of all biomass materials. In contrast, potassium peaked only in December, indicating that it might be a more specific tracer for wood-burning.

Keywords: Polycyclic aromatic hydrocarbon; PAH; Seasonal variation; Spatial variation; Retene

Simulation and evaluation of 2010 emission control scenarios in a Mediterranean area by Isabelle Coll; Fanny Lasry; Sylvain Fayet; Alexandre Armengaud; Robert Vautard (pp. 4194-4204).

At the onset of the 2010 statutory deadline for the respect of the European National Emission Ceiling directive, two questions arise. Will the engaged regulations for the respect of ozone air quality thresholds be fully efficient on the most polluted regions? How can we design the continuation of ozone control in those areas? This study is based on refined 3D modelling studies over a French Mediterranean region. It compares 2001 and 2003 situations with several prospective 2010 emission scenarios with, for the first time, the evaluation of local action plans. The degree of compliance with air quality regulation is investigated and the impact of emission control on the local potential for ozone formation is discussed. The results show that current efforts on emissions, although substantial and efficient, are not sufficient yet to abrogate all the ozone threshold exceedances. They also highlight the gap between regulatory and effective emission control, as well as the need for regional regulations to complete national efforts. Finally, the simulations indicate that large-scale emission control significantly helps reducing rural ozone (−20 ppbv) but affects much fewer (−2 to −10 ppbv) the highest peaks. The continuation and the strengthening of ozone policies under their current form in such regions are considered.

Keywords: Emission scenario; Model; ESCOMPTE; Ozone; Environmental policy; Mediterranean area

Investigating the chemical nature of humic-like substances (HULIS) in North American atmospheric aerosols by liquid chromatography tandem mass spectrometry by Elizabeth A. Stone; Curtis J. Hedman; Rebecca J. Sheesley; Martin M. Shafer; James J. Schauer (pp. 4205-4213).

The high-molecular weight water-soluble organic compounds present in atmospheric aerosols underwent functional-group characterization using liquid chromatography tandem mass spectrometry (LC-MS/MS), with a focus on understanding the chemical structure and origins of humic-like substances (HULIS) in the atmosphere. Aerosol samples were obtained from several locations in North America at times when primary sources contributing to organic aerosol were well-characterized: Riverside, CA, Fresno, CA, urban and peripheral Mexico City, Atlanta, GA, and Bondville, IL. Chemical analysis targeted identification and quantification of functional groups, such as aliphatic, aromatic, and bulk carboxylic acids, organosulfates, and carbohydrate-like substances that comprise species with molecular weights (MW) 200–600 amu. Measured high-MW functional groups were compared to modeled primary sources with the purpose of identifying associations between aerosol sources, high-MW aerosol species, and HULIS. Mobile source emissions were linked to high-molecular weight carboxylic acids, especially aromatic acids, biomass burning was associated with carboxylic acids and carbohydrate-like substances, and secondary organic aerosol (SOA) correlated well with the total amount of HULIS measured, whereas organosulfates showed no correlation with aerosol sources and exhibited unique spatial trends. These results suggested the importance of motor vehicles, biomass burning, and SOA as important sources of precursors to HULIS. Structural characteristics of atmospheric HULIS were compared to terrestrial humic and fulvic acids and revealed striking similarities in chemical structure, with the exception of organosulfates which were unique to atmospheric HULIS.

Keywords: HULIS; LC-MS/MS; Organic aerosols; Water-soluble organic carbon; Organosulfates

Organic composition of fogwater in the Texas–Louisiana gulf coast corridor by Suresh Raja; Ravikrishna Raghunathan; Raghava R. Kommalapati; Xinhua Shen; Jeffrey L. Collett Jr.; Kalliat T. Valsaraj (pp. 4214-4222).

Fogwater and air samples were collected in Baton Rouge between November 2004–February 2005 and during February 2006 at Houston. Organic compounds present in the fog samples were detected, quantified and then grouped into different compound classes based on molecular size, solubility and polarity using gas chromatography/mass spectrometry, high performance liquid chromatography with diode array detection and ion chromatography. Organic compounds were grouped as n-alkanes, aromatics and polycyclic aromatics, carbonyls, alcohols, amides and esters. Organic compounds in fog and air samples in Houston indicated clear urban/industrial anthropogenic origin, while compounds detected in Baton Rouge fog and air samples showed a mix of both agricultural and urban/industrial anthropogenic inputs. Among the various polycyclic aromatic compounds detected, the total concentration of naphthalene and its derivatives was 2.8 μg m⁻³ in Houston and 0.08 μg m⁻³ in Baton Rouge air. Analysis of concentrations of organic compounds pre- and post- fog revealed that compounds with low vapor pressure had higher scavenging efficiency in fog sampled at the two locations. Concentrations of organic compounds in fog samples were higher than those predicted by conventional air-water Henry's law equilibrium. Observed higher concentrations in the aqueous phase were modeled accounting for surface adsorption and accumulation of gas phase species and the presence of humic-like substances in fogwater.

Keywords: Organics; Humic substances; Fog; Air pollution; Pollutant transport

Wet deposition of mercury in the U.S. and Canada, 1996–2005: Results and analysis of the NADP mercury deposition network (MDN) by Eric M. Prestbo; David A. Gay (pp. 4223-4233).

One of the most critical measurements needed to understand the biogeochemical cycle of mercury, and to verify atmospheric models, is the rate of mercury wet-deposition. The Mercury Deposition Network (MDN) operates sites across North America to monitor total mercury in wet-deposition. MDN's primary goal is to provide both spatial and temporal continental-scale observations of mercury wet-deposition fluxes to support researchers, modelers, policy-makers and the public interest. MDN represents the only continental-scale mercury deposition database with a >10-year record of continuous values. This study provides analysis and interpretation of MDN observations at 10 years (1996–2005) with an emphasis on investigating whether rigorous, statistically-significant temporal trends and spatial patterns were present and where they occurred. Wet deposition of mercury ranges from more than 25 μg m⁻² yr in south Florida to less than 3 μg m⁻² yr in northern California. Volume-weighted total mercury concentrations are statistically different between defined regions overall (Southeast ≈ Midwest > Ohio River > Northeast), with the highest in Florida, Minnesota, and several Southwest locations (10–16 ng L⁻¹). Total mercury wet-deposition is significantly different between defined regions (Southeast > Ohio River > Midwest > Northeast). Mercury deposition is strongly seasonal in eastern North America. The average mercury concentration is about two times higher in summer than in winter, and the average deposition is approximately more than three times greater in summer than in winter. Forty-eight sites with validated datasets of five years or more were tested for trends using the non-parametric seasonal Kendall trend test. Significant decreasing mercury wet-deposition concentration trends were found at about half of the sites, particularly across Pennsylvania and extending up through the Northeast.

Keywords: Mercury; Wet deposition; MDN; Temporal trends

Exposure to ultrafine and fine particles and noise during cycling and driving in 11 Dutch cities by Hanna Boogaard; Frank Borgman; Jaap Kamminga; Gerard Hoek (pp. 4234-4242).

Recent studies have suggested that exposures during traffic participation may be associated with adverse health effects. Traffic participation involves relatively short but high exposures. Potentially relevant exposures include ultrafine particles, fine particles (PM_2.5) and noise.Simultaneously, detailed real time exposure of particle number concentration (PNC), PM_2.5 and noise has been measured while driving and cycling 12 predefined routes of approximately 10–20 min duration. Sampling took place in eleven medium-sized Dutch cities on eleven weekdays in August till October 2006. To investigate variability in cyclists exposure, we systematically collected information on meteorology, GPS coordinates, type of road, traffic intensity, passing vehicles and mopeds while cycling.The overall mean PNC of car drivers was 5% higher than the mean PNC of cyclists. The overall mean concentration of PM_2.5 in the car was 11% higher than during cycling. Slightly higher 1-min peak concentrations were measured in the car (PNC 14%; PM_2.5 29% for 95-percentiles). Shorter duration peaks of PNC were higher during cycling (43% for 99-percentile of 1-s averages). Peaks in PNC typically last for less than 10 s. A large variability of exposure was found within and between routes. Factors that significantly predicted PNC variability during cycling were: passing vehicles (mopeds, cars), waiting for traffic lights, passing different types of (large) intersections and bicycle lanes and bike paths close to motorized traffic. No relation was found between PM_2.5 and those predictor variables. The correlation between PNC and noise was moderate (median 0.34). PM_2.5 had very low correlations with PNC and noise.PNC and PM_2.5 exposure of car drivers was slightly higher than that of cyclists. PNC was largely uncorrelated with PM_2.5 and reflected local traffic variables more than PM_2.5. Different factors were associated with high PNC and high noise exposures.

Keywords: Cycling; Driving; Ultrafine particles; Fine particles; Noise

Total suspended particulate matter and toxic elements indoors during cooking with yak dung by Shichang Kang; Chaoliu Li; Feiyue Wang; Qianggong Zhang; Zhiyuan Cong (pp. 4243-4246).

Many herders in the Tibetan Plateau still inherit the traditional lifestyle, including living in tents and burning yak dung for fuel. This short correspondence reports a pilot study on indoor air quality in the nomadic tents in the Nam Co region, inland Tibetan Plateau. The results showed very high concentrations of total suspended particles (TSP), averaging at 4.45 mg m⁻³ during the cooking/heating period (with daily value of 3.16 mg m⁻³). Elevated concentrations of toxic element Cd, As and Pb were also found within the tents, averaging 3.16 μg m⁻³, 35.00 μg m⁻³, and 81.39 μg m⁻³ for a day, respectively, which were not only far higher than those of WHO indoor air quality guidelines, but also more than 10⁴–10⁶ times higher than the outdoor air level in the Nam Co area. The study raises serious concerns over the health of Tibetan herders following their long-term exposure to the tent air.

Keywords: Indoor air pollution; Nomadic tent; Total suspended particles (TSP); Toxic elements; Tibetan plateau

The radiative efficiency of HCF₂OCF₂OCF₂CF₂OCF₂H (H-Galden 1040x) revisited by T.J. Wallington; M.D. Hurley; O.J. Nielsen (pp. 4247-4249).

The infrared spectrum of HCF₂OCF₂OCF₂CF₂OCF₂H (CAS# 188690-77-9) has been re-measured. The integrated absorption intensity over the range 1000–1500cm⁻¹ measured in the present work is (6.65±0.33)×10⁻¹⁷cm² molecule⁻¹cm⁻¹ in 700Torr of air at 296K. The radiative efficiency of HCF₂OCF₂OCF₂CF₂OCF₂H is calculated to be 1.02Wm⁻²ppb⁻¹. The value reported in the 2007 Intergovernmental Panel on Climate Change (IPCC) report is approximately 35% larger reflecting what we believe to be an erroneously high value for the absorption strength of HCF₂OCF₂OCF₂CF₂OCF₂H adopted by the IPCC.

Keywords: Radiative forcing; Climate change; H-Galden; Atmospheric chemistry

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Atmospheric Environment (v.43, #27)