Impact Of Ozone Research Articles

Foliar symptoms on Viburnum lantana reflect annual changes in summer ozone concentration in Trentino (northern Italy)

The frequency of Viburnum lantana L. plants showing visible foliar symptoms (VFS) was assessed in Trentino, north Italy in 2010, 2012, 2014 and 2015. The assessment was based on a sub-sample (n=10) of the ViburNeT observation plots network installed in 2010 according to a stratified random design. Depending on the year, a range of 193–232 plants were assessed during August. The frequency of symptomatic plants varied from 20.7 to 50.6%. Mean May-July hourly ozone concentration measured by conventional monitors over the same area and period varied from 37.9 to 45.8ppb. There was a consistent time pattern between ozone and VFS. Consistency is confirmed if also a pilot survey carried out in 2009 is taken into account. Results are promising and supportive of the use of V. lantana as in-situ bioindicator for monitoring ozone impact on vegetation in forest areas.

Impact of tropospheric ozone on terrestrial biodiversity: A literature analysis to identify ozone sensitive taxa

Tropospheric ozone has long been known as highly phytotoxic. However, currently hardly anything is known whether this air pollutant can also pose a threat to the overall biodiversity in terrestrial ecosystems. Identifying the relative ozone sensitivities of relevant taxa or species can be a first step in an assessment if biodiversity is at risk from ozone. A literature survey was conducted describing experimental and observational results of exposure of organisms and particularly plant species to ozone at environmentally relevant concentrations. For plants ozone effects considered were vegetative growth (e.g. biomass of shoots, foliage, single leaves, stems, and roots), reproduction (number and biomass of seeds and flowers), species development, and symptoms of visible foliar injury. A total of 474 literature references were evaluated which described such effects. For crop plants 54 species with 350 varieties could be considered, while (semi)natural vegetation was represented by 465 vascular plant species comprising 298 herbaceous and 165 woody plant species. Overall, these ozone studies cover only a small fraction of the entire global flora. About two third of woody and about one half of native herbaceous plant species investigated so far have been described as ozone sensitive in at least one study. Ozone sensitivity is slightly higher with respect to visible leaf injury as compared to growth effects, and herbs and deciduous tree species are more responsive than grasses and coniferous trees. Observational results from field surveys conducted along ozone gradients to assess ecosystem effects of ozone in North America and Europe revealed visible macroscopic leaf injuries for 258 herbaceous species. However, these findings often have not been verified under experimental ozone exposure. Albeit the numbers of ozone studies related to a particular plant family varied considerably, high proportions of ozone sensitive species were found e.g. for the families Myrtaceae, Salicaceae and Onograceae, while low proportions of ozone sensitive species were found e.g. for the families Brassicaceae, Boraginaceae and Plantaginaceae. Intra-specific variations of ozone sensitivity of vascular plants were primarily detected in crop species (e.g. wheat, soybean, snap bean, clover, rice), most often derived from screening studies of cultivars for their relative ozone sensitivity/tolerance to ozone. In some cases intra-specific variation of ozone sensitivity is also true for different populations of woody and herbaceous plant species, which often resulted from temporal or spatial differentiation of the relative ozone susceptibility. Therefore, there is some evidence that ozone pollution in the past has already affected plant selection and modified the genetic pool of ozone sensitive genotypes. Information on direct ozone effects on species other than vascular plants (e.g. ferns, mosses, fungi, algae, vertebrates) is very poor or irrelevant, i.e. ozone sensitivities for these taxa could not be described. This is also true for organisms like microbes, arthropods or insects which have not been tested so far for their responses to direct ambient ozone exposure. However, these organisms may be indirectly impaired by ozone via loss of vitality of the plant system to which they are associated.

Stomatal conductance models for ozone risk assessment at canopy level in two Mediterranean evergreen forests

Forests in Mediterranean Europe are located in a hot spot for tropospheric ozone formation. We applied two canopy-level stomatal conductance models (Jarvis-type and Ball-Woodrow-Berry models) to two Mediterranean evergreen forests (Umbrella pine at San Rossore, and Holm oak at Castelporziano, in central Italy), which is essential for assessing ozone impact on forests via the stomatal flux-based approach. Parameterizations of the models was carried out by the Eddy Covariance technique. Both Jarvis-type and Ball-Woodrow-Berry models well explained the observed stomatal conductance and stomatal ozone flux in both forests. Maximum stomatal conductance was 72% higher in Umbrella pine than in Holm oak, leading to higher stomatal ozone flux. Inclusion of a soil water function improved the performance of the Jarvis-type model for the estimation of stomatal ozone flux. We found contrasting results concerning the coefficient m (the slope of the photosynthesis-stomatal conductance relationship) in the Ball-Woodrow-Berry model between the two forests: while m was constant for varying soil water status in the Holm oak forest, it declined with soil drying in the Umbrella pine forest. This may result from higher stomatal sensitivity to drought in Umbrella pine as a response to avoid drought stress. Overall, these results advance our understanding of ozone risk assessment in Mediterranean forests.

The impact of elevated ozone on the ornamental features of two flowering plants (Tagetes erecta Linn. and Petunia hybrida Vilm.)

There has been little investigation into the effects of ozone (O3) on flowering plants around settlements, even though such plants are known to be threatened by elevated O3. In this study, we used open-top chambers to assess the ornamental value of marigolds (Tagetes erecta Linn.) and four petunia (Petunia hybrid Vilm.) varieties in terms of their growth and physiological responses to elevated O3. The aboveground biomass decreased by 7.4% in marigolds and by 19.4-23.6% in four varieties of petunia in response to elevated O3. The underground biomass decreased by 22.0% in marigolds and by 30.8-53.8% in four petunia varieties treated with elevated O3. Flower biomass and diameter were markedly reduced by elevated O3 in petunias, but not in marigolds. O3 also accelerated leaf yellowing in different plant species and varieties, owing to a higher degree of degradation of chlorophyll than carotenoids, as well as an increase in flavonoid contents. Thus, O3 stress responses should be considered when choosing flowering plants for their ornamental value.

The impact of elevated ozone on the ornamental features of two flowering plants (Tagetes erecta Linn. and Petunia hybrida Vilm.)

The impact of elevated ozone on the ornamental features of two flowering plants (Tagetes erecta Linn. and Petunia hybrida Vilm.)

Ozone effects on the physiology and marketable biomass of leafy vegetables under Mediterranean conditions: Spinach (Spinacia oleracea L.) and Swiss chard (Beta vulgaris L. var. cycla)

Two open-top chamber experiments were carried out at a continental and a coastal location in Spain to test the ozone sensitivity of spinach (Spinacia oleracea L.) and Swiss chard (Beta vulgaris L. var. cycla) under Mediterranean conditions. Three cultivars of spinach and two cultivars of Swiss chard currently grown in commercial fields were screened for ozone tolerance in terms of marketable yield. Different physiological parameters were measured to identify traits related with this tolerance and ozone effects on yield quality.All the spinach and Swiss chard cultivars tested in this study were sensitive to ozone in terms of marketable biomass yield. The commercial biomass decreased on average between 13.8 and 17.9% in spinach and between 0 and 20.1% in Swiss chard at a continental and a coastal site, respectively, after two months of ozone exposure under ambient plus 40ppb of ozone concentration compared to charcoal-filtered air. Ozone effects on the marketable yield were associated with the appearance of leaf visible injury and by reductions in the photosynthetic activity of the leaves.Swiss chard cultivars were generally more ozone tolerant than spinach cultivars. However, the ozone sensitivity differed between cultivars of the same species and effects were more pronounced at the coastal site, where environmental growing conditions favoured plant growth more than at the continental site.The physiological traits analysed (photosynthesis and gas exchange parameters and ascorbate concentration and redox status) were not related to differences in ozone tolerance between cultivars. Ozone effects on leaf nitrogen content and greenness reflected the impact of ozone on yield quality parameters for leafy vegetables, such as leaf nitrate concentration and the marketable value.These results show that leafy vegetables can be more sensitive to ozone than other horticultural crops like tomato, which is used as a representative crop in risk assessments of ozone effects on horticultural production in Europe.

Research on the influence of ozone dissolved in the fuel-water emulsion on the parameters of the CI engine

The article presents the results of empirical research on the impact of ozone dissolved in fuel-water emulsion on combustion process and concentration of toxic substances in CI engine. The effect of ozone presence in the emulsion and its influence on main engine characteristics (power, torque, fuel consumption) and selected parameters that characterize combustion process (levels of pressures and temperatures in combustion chamber, period of combustion delay, heat release rate, fuel burnt rate) is shown. The change in concentration of toxic components in exhausts gases when engine is fueled with ozonized emulsion was also identified. The empirical research and their analysis showed significant differences in the combustion process when fuel-water emulsion containing ozone was used. These differences include: increased power and efficiency of the engine that are accompanied by reduction in time of combustion delay and beneficial effects of ozone on HC, PM, CO and NOX emissions.

Long-term variations of noctilucent clouds at ALOMAR

Noctilucent clouds (NLC) are measured by the Rayleigh/Mie/Raman-lidar at the ALOMAR research facility in Northern Norway (69°N, 16°E) since 1994. The data set contains about 2860h of NLC detections and is investigated for the first time regarding trends. NLC properties depend on cloud brightness which is taken into account by the use of several cloud classes, related to brightness ranges. For NLC brighter than the long-term detection limit and strong NLC, respectively, the trend terms show increasing occurrence frequency (+9%/dec and+5%/dec) and brightness (+1.7×10−10 m−1 sr−1/dec and +1.5×−10 m−1 sr−1/dec) from 1998 to 2015. In the same period the altitude of faint and long-term limit clouds decreases (−66m/dec and −108m/dec). Over the entire time period of 22 years strong clouds show an increasing altitude by +76m/dec. NLC properties are affected differently by solar and atmospheric parameters. In general, Lyman-α and stratospheric ozone impact all three NLC parameters, temperature at 83km impacts mainly the NLC altitude. Time series of RMR lidar and SBUV satellite instruments match best for NLC occurrence frequency and brightness when restricting SBUV to the morning data at longitudes around ALOMAR (64–74°N, 8–24°E/0–9LT). This suggests longitudinal dependent trends, which is confirmed by trend investigations of longitudinal subsets of the SBUV data set.

Robust response of the Amundsen Sea Low to stratospheric ozone depletion

AbstractThe effect of stratospheric ozone depletion on the Amundsen Sea Low (ASL), a climatological low‐pressure center important for the climate of West Antarctica, remains uncertain. Using state‐of‐the‐art climate models, we here show that stratospheric ozone depletion can cause a statistically significant deepening of the ASL in summer with an amplitude of approximately 1 hPa per decade. We are able to attribute the modeled changes in the ASL to stratospheric ozone depletion by contrasting ensembles of historical integrations with and without a realistic ozone hole. In the presence of very large natural variability, the robustness of the ozone impact on the ASL is established by (1) examining ensembles of model runs to isolate the forced response, (2) repeating the analysis with two different climate models, and (3) considering the entire period of stratospheric ozone depletion, the beginning of which predates the satellite era by a couple of decades.

Influence of injection parameters, ozone seeding and residual NO on a Gasoline Compression Ignition (GCI) engine at low load

The main objective of this work was to evaluate the potential of ozone to overcome the low load limitations of Direct-Injection Gasoline Compression Ignition (D-I GCI) engines. Experiments were performed in a single-cylinder diesel engine fuelled with directly-injected 95 RON gasoline at 2bar IMEP. Engine speed was set to 1500rpm. Intake pressure was set to 1bar in order to investigate typical low load operating conditions. Chemical computation revealed that the O atoms coming from the O3 molecules and responsible for promoting fuel autoignition exhibited a maximum concentration near 30° before TDC. Experiments showed that a narrow umbrella angle extends the early injections range up to -60 CAD, better matching with ozone decomposition. Injection timing can be employed to better exploit the oxidizing effect of ozone, which proved to be dependent on local conditions of temperature, equivalence ratio, and concentration of O atoms and of the residual NO trapped after each combustion cycle. Results showed that the impact of ozone is generally higher at early injection, but that interaction between O3 molecules and NO contained in the trapped gas can drastically reduce or even make the promoting effect of ozone ineffective. Finally, seeding the intake of the engine with ozone is shown to be an effective way to improve the autoignition propensity of high octane fuel and to overcome the low load limitation of D-I GCI engines.

Photochemical model evaluation of the ground-level ozone impacts on ambient air quality and vegetation health in the Alberta oil sands region: Using present and future emission scenarios

One of the potential environmental issues associated with oil sands development is increased ozone formation resulting from NOX and volatile organic compound emissions from bitumen extraction, processing and upgrading. To manage this issue in the Athabasca Oil Sands Region (AOSR) in northeast Alberta, a regional multi-stakeholder group, the Cumulative Environmental Management Association (CEMA), developed an Ozone Management Framework that includes a modelling based assessment component. In this paper, we describe how the Community Multi-scale Air Quality (CMAQ) model was applied to assess potential ground-level ozone formation and impacts on ambient air quality and vegetation health for three different ozone precursor cases in the AOSR. Statistical analysis methods were applied, and the CMAQ performance results met the U.S. EPA model performance goal at all sites. The modelled 4th highest daily maximum 8-h average ozone concentrations in the base and two future year scenarios did not exceed the Canada-wide standard of 65 ppb or the newer Canadian Ambient Air Quality Standards of 63 ppb in 2015 and 62 ppb in 2020. Modelled maximum 1-h ozone concentrations in the study were well below the Alberta Ambient Air Quality Objective of 82 ppb in all three cases. Several ozone vegetation exposure metrics were also evaluated to investigate the potential impact of ground-level ozone on vegetation. The chronic 3-months SUM60 exposure metric is within the CEMA baseline range (0–2000 ppb-hr) everywhere in the AOSR. The AOT40 ozone exposure metric predicted by CMAQ did not exceed the United Nations Economic Commission for Europe (UN/ECE) threshold of concern of 3000 ppb-hr in any of the cases but is just below the threshold in high-end future emissions scenario. In all three emission scenarios, the CMAQ predicted W126 ozone exposure metric is within the CEMA baseline threshold of 4000 ppb-hr. This study outlines the use of photochemical modelling of the impact of an industry (oil sands) on ground-level ozone levels as an air quality management tool in the AOSR. It allows an evaluation of the relationships between the pollutants emitted to the atmosphere and potential ground level ozone concentrations throughout the AOSR thereby extending the spatial coverage of the results beyond the monitoring network and also allowing an assessment of the potential impacts of possible future emission cases.

Assessing the impact of ambient ozone (O3) on the growth and yield of potato genotypes (Solanum tuberosum L.) by using exposure indices over the high altitude of western Ghats location in Southern India

Assessing the impact of ambient ozone (O3) on the growth and yield of potato genotypes (Solanum tuberosum L.) by using exposure indices over the high altitude of western Ghats location in Southern India

Evaluation of the impact of atmospheric ozone and aerosols on the horizontal global/diffuse UV Index at Livorno (Italy)

A study was conducted at Livorno (Italy) to evaluate the impact of atmospheric aerosols and ozone on the solar UV radiation and its diffuse component at ground in clear sky conditions. Solar UV radiation has been quantified in terms of UV Index (UVI), following the ISO 17166:1999/CIE S007/E-1998 international standard. UVI has been calculated by exploiting the libRadtran radiative transfer modelling software as a function of both the Aerosols Optical Depth (AOD) and the Total Ozone Column (TOC). In particular AOD and TOC values have been remotely sensed by the Ozone Monitoring Instrument (OMI) on board the NASA's EOS (Earth Observing System) satellites constellation. An experimental confirmation was also obtained by exploiting global UVI ground-based measurements from the 26/9/14 to 12/8/15 and diffuse UVI ground-based measurements from the 17/5/15 to 12/8/15. For every considered value of Solar Zenith Angle (SZA) and atmospheric condition, estimates and measurements confirm that the diffuse component contributes for more than 50% on the global UV radiation. Therefore an exposure of human skin also to diffuse solar UV radiation can be potentially harmful for health and need to be accurately monitored, e.g. by exploiting innovative applications such as a mobile app with a satellite-based UV dosimeter that has been developed. Global and diffuse UVI variations due to the atmosphere are primarily caused by the TOC variations (typically cyclic): the maximum TOC variation detected by OMI in the area under study leads to a corresponding variation in global and diffuse UVI of about 50%. Aerosols in the area concerned, mainly of maritime nature, have instead weaker effects causing a maximum variation of the global and diffuse UVI respectively of 9% and 35% with an SZA of 20° and respectively of 13% and 10% with an SZA of 60°.

Biomass and physiological responses of Quercus robur (L.) young trees during 2 years of treatments with different levels of ozone and nitrogen wet deposition

The root biomass of oak young trees significantly decreased after 2 years of exposure to high levels of ozone, but increased nitrogen wet deposition tended to partly contrast this effect. A 2-year Open-Top Chamber (OTC) experiment with young Quercus robur trees that were exposed to different levels of ozone (O3) and nitrogen deposition was performed in Curno (Northern Italy) for the FP7 Project ECLAIRE. The plants were exposed to four levels of ozone (−40 % of ambient ozone in charcoal-filtered OTCs, −5 % in non-filtered OTCs, and +30 and +75 % in O3-enriched OTCs) and two levels of nitrogen wet deposition (tap water and tap water +70 kg N ha−1 year−1). The stomatal conductance and A/Ci response curves were measured during the two experimental seasons, and in October, the plant dry biomass partition between the roots and stem was assessed. Oak plants were moderately sensitive to O3. After the second year of treatments, the dose–response relationships based on the O3 stomatal flux indicated a 4.6 % of root biomass loss and a 12.1 % of reduction of the number of leaves per 10 mmol O3 m−2 absorbed by plants grown with no nitrogen addition. Ozone also decreased both the stomatal conductance and the maximum carboxylation rate allowed by Rubisco (V cmax) during the first year of treatments. However, the effect on V cmax was lost during the second year, and the plants showed an uncoupling between leaf-level physiological responses and plant-level biomass responses. Increased nitrogen deposition enhanced the growth of plants and partially mitigated the O3 impact on biomass and physiology, but no significant effect of the interaction between the two factors was found. The data that were collected could contribute to the definition of the O3 dose–response relationships based on biomass losses for deciduous trees in Southern Europe climatic conditions and could improve the O3 risk assessment models by providing new information about the effect of increased nitrogen deposition on the ozone impact.

Impacts of flare emissions from an ethylene plant shutdown to regional air quality

Critical operations of chemical process industry (CPI) plants such as ethylene plant shutdowns could emit a huge amount of VOCs and NOx, which may result in localized and transient ozone pollution events. In this paper, a general methodology for studying dynamic ozone impacts associated with flare emissions from ethylene plant shutdowns has been developed. This multi-scale simulation study integrates process knowledge of plant shutdown emissions in terms of flow rate and speciation together with regional air-quality modeling to quantitatively investigate the sensitivity of ground-level ozone change due to an ethylene plant shutdown. The study shows the maximum hourly ozone increments can vary significantly by different plant locations and temporal factors including background ozone data and solar radiation intensity. It helps provide a cost-effective air-quality control strategy for industries by choosing the optimal starting time of plant shutdown operations in terms of minimizing the induced ozone impact (reduced from 34.1 ppb to 1.2 ppb in the performed case studies). This study provides valuable technical supports for both CPI and environmental policy makers on cost-effective air-quality controls in the future.

Forests and ozone: productivity, carbon storage, and feedbacks.

Tropospheric ozone is a serious air-pollutant, with large impacts on plant function. This study demonstrates that tropospheric ozone, although it damages plant metabolism, does not necessarily reduce ecosystem processes such as productivity or carbon sequestration because of diversity change and compensatory processes at the community scale ameliorate negative impacts at the individual level. This study assesses the impact of ozone on forest composition and ecosystem dynamics with an individual-based gap model that includes basic physiology as well as species-specific metabolic properties. Elevated tropospheric ozone leads to no reduction of forest productivity and carbon stock and to increased isoprene emissions, which result from enhanced dominance by isoprene-emitting species (which tolerate ozone stress better than non-emitters). This study suggests that tropospheric ozone may not diminish forest carbon sequestration capacity. This study also suggests that, because of the often positive relationship between isoprene emission and ozone formation, there is a positive feedback loop between forest communities and ozone, which further aggravates ozone pollution.

Ozone Impacts on Carbon Dynamics in Cotton

Ozone (O3) is a secondary atmospheric pollutant that causes widespread damage to vegetation, including cotton. The high temperatures and abundant sunlight that lead to good cotton yields also lead to production of O3. The early crop loss experiments of the 1970s identified upland cotton as particularly sensitive to O3. Exposure to ambient concentrations of O3 resulted in a 10 to >15% loss in economic yield. More recent experiments with modern cultivars have confirmed damage to upland and Pima cultivars but have not assessed yield loss under agronomic conditions. It is likely that selection for yield in high O3 environments has led to inadvertent selection for tolerance to O3. Ozone reduces yield and fiber quality, mediated by O3-induced changes in gross photosynthesis, respiration, and translocation of current photosynthate out of source leaves. Ozone typically reduces root development and the root-to-shoot biomass ratio, which has secondary effects on plant growth and development and on water relations. Ozone also reduces stomatal conductance as a primary defense against entry of O3 into the plant, but this also restricts entry of CO2 and therefore photosynthesis. Ozone is clearly phytotoxic and impacts cotton as well as other species. Recent research has led to understanding many aspects of the mechanism of O3 damage and could lead to targeted approaches to improving O3 tolerance, and therefore, yield in O3-impacted production areas.

Chemical and Natural Plant Extract in Ameliorating Negative Impact of Tropospheric Ozone on Wheat Crop: A Case Study in a Part of Semiarid North West India

ABSTRACTCurrent rise in concentration of tropospheric ozone (O3) has deleterious effect on growth and yield of crops. Wheat is one of the most O3 sensitive crops. Application of Chemical antioxidants may be beneficial to lessen the harmful effects of O3 on crops. A two year study growing wheat (variety PBW550) was carried at the farms of Indian Agricultural Research Institute, New Delhi in 2010–11 and 2011–12 to evaluate the efficacy of some natural and environment friendly antioxidant chemicals in ameliorating the negative impacts of elevated ozone on growth and productivity of wheat. The treatments were i) charcoal filtered air (CF) ii) 1% ascorbic acid (AA), iii) 100 ppm quercetin (Q), iv) 10% marigold leaves extract (Tagetes patula var pusa arpita) (T) and v) elevated O3 control (C). Additional 25–35 ppb of O3 over the ambient levels was maintained in all open top chambers except the CF treatment. The seasonal daily average O3 concentration in ambient air was 38 ppb in 2010–11 and 29 ppb in 2011–12 during the crop growth period. The exogenous application of antioxidants increased the levels of endogenous leaf ascorbic acid. The activity of antioxidant enzymes (superoxide dismutase, catalase and peroxidase) was lowered by 5 to 34% in antioxidants sprayed plants as compared to elevated O3 control (C). The application of antioxidants increased the yield of wheat by 23–26% in AA, 13–15% in Q and 8–10% in T as compared to C. The micronutrient (Cu, Fe, Zn and Mn) content of wheat grains on application of exogenous ascorbic acid was higher. The application of antioxidant chemicals was effective in alleviating the negative impacts of elevated O3 on enzyme activity and nutritional quality of wheat which increased the growth and yield of the crop

Ground-Level Ozone Following Astrophysical Ionizing Radiation Events: An Additional Biological Hazard?

Astrophysical ionizing radiation events such as supernovae, gamma-ray bursts, and solar proton events have been recognized as a potential threat to life on Earth, primarily through depletion of stratospheric ozone and subsequent increase in solar UV radiation at Earth's surface and in the upper levels of the ocean. Other work has also considered the potential impact of nitric acid rainout, concluding that no significant threat is likely. Not yet studied to date is the potential impact of ozone produced in the lower atmosphere following an ionizing radiation event. Ozone is a known irritant to organisms on land and in water and therefore may be a significant additional hazard. Using previously completed atmospheric chemistry modeling, we examined the amount of ozone produced in the lower atmosphere for the case of a gamma-ray burst and found that the values are too small to pose a significant additional threat to the biosphere. These results may be extended to other ionizing radiation events, including supernovae and extreme solar proton events.

Instantaneous longwave radiative impact of ozone: an application on IASI/MetOp observations

Abstract. Ozone is an important greenhouse gas in terms of anthropogenic radiative forcing (RF). RF calculations for ozone were until recently entirely model based, and significant discrepancies were reported due to different model characteristics. However, new instantaneous radiative kernels (IRKs) calculated from hyperspectral thermal IR satellites have been able to help adjudicate between different climate model RF calculations. IRKs are defined as the sensitivity of the outgoing longwave radiation (OLR) flux with respect to the ozone vertical distribution in the full 9.6 μm band. Previous methods applied to measurements from the Tropospheric Emission Spectrometer (TES) on Aura rely on an anisotropy approximation for the angular integration. In this paper, we present a more accurate but more computationally expensive method to calculate these kernels. The method of direct integration is based on similar principles to the anisotropy approximation, but it deals more precisely with the integration of the Jacobians. We describe both methods and highlight their differences with respect to the IRKs and the ozone longwave radiative effect (LWRE), i.e., the radiative impact in OLR due to absorption by ozone, for both tropospheric and total columns, from measurements of the Infrared Atmospheric Sounding Interferometer (IASI) onboard MetOp-A. Biases between the two methods vary from −25 to +20 % for the LWRE, depending on the viewing angle. These biases point to the inadequacy of the anisotropy method, especially at nadir, suggesting that the TES-derived LWREs are biased low by around 25 % and that chemistry–climate model OLR biases with respect to TES are underestimated. In this paper we also exploit the sampling performance of IASI to obtain first daily global distributions of the LWRE, for 12 days (the 15th of each month) in 2011, calculated with the direct integration method. We show that the temporal variation of global and latitudinal averages of the LWRE shows patterns which are controlled by changes in the surface temperature and ozone variation due to specific processes, such as the ozone hole in the polar regions and stratospheric intrusions into the troposphere.