Exposure to ground-level ozone is a concern for both humans and vegetation, so accurate prediction of ozone time series is of great importance. However, conventional as well as emerging methods have deficiencies in predicting time series when a superposition of differently pronounced oscillations on various time scales is present. In this paper, we propose a meteorologically motivated filtering method of time series data, which can separate oscillation patterns, in combination with different multibranch neural networks. To avoid phase shifts introduced by using a causal filter, we combine past observation data with a climatological estimate about the future to be able to apply a noncausal filter in a forecast setting. In addition, the forecast in the form of the expected climatology provides some a priori information that can support the neural network to focus not merely on learning a climatological statistic. We apply this method to hourly data obtained from over 50 different monitoring stations in northern Germany situated in rural or suburban surroundings to generate a prediction for the daily maximum 8-hr average values of ground-level ozone 4 days into the future. The data preprocessing with time filters enables simpler neural networks such as fully connected networks as well as more sophisticated approaches such as convolutional and recurrent neural networks to better recognize long-term and short-term oscillation patterns like the seasonal cycle and thus leads to an improvement in the forecast skill, especially for a lead time of more than 48 hr, compared to persistence, climatological reference, and other reference models.

The production of Amarone wine is governed by a disciplinary guideline to preserve its typical features; however, postharvest infections by the fungus Botrytis cinerea (B. cinerea) not only represent a phytosanitary problem but also cause a significant loss of product. In this study, we tested a treatment with mild ozoniztion on grapes for Amarone wine production during withering in the fruttaio (the environment imposed by the disciplinary guideline) and evaluated the impact on berry features by a multimodal imaging approach. The results indicate that short and repeated treatments with low O3 concentrations speed up the naturally occurring berry withering, probably inducing a reorganization of the epicuticular wax layer, and inhibit the development of B. cinerea, blocking the fungus in an intermediate vegetative stage. This pilot study will pave the way to long-term research on Amarone wine obtained from O3-treated grapes.

Field experiments were conducted over a 4-yr period to determine the influence of selected herbicides on ozone injury in tobacco (Nicotiana tabacum L.). Isopropalin (2,6-dinitro-N,N-dipropylcumidine), pebulate (S-propyl butylethylthiocarbamate), and diphenamid (N,N-dimethyl-2,2-diphenylacetamide) were applied at the recommended rates of 1.7, 4.5, and 4.5 kg/ha, respectively. Treatment of tobacco plants with isopropalin or diphenamid reduced oxidant injury for the first 2 to 4 weeks after transplanting, but not later in the season. Pebulate had no consistent affect on the sensitivity of tobacco to ozone.

Since the first identification of glyphosate resistance in horseweed in California in 2005, the glyphosate-sensitive (GS) biotype has become rare, whereas the glyphosate-resistant (GR) biotype has become dominant in the eastern San Joaquin Valley (SJV). This is an area exposed to regular usage of glyphosate and to high levels of ambient ground-level ozone (O3). A previous study showed that SJV biotypes of GR are more robust than GS in the absence of ozone. This advantage was reduced, though not eliminated, at elevated O3. This suggests that the rapid evolution of resistance to glyphosate was not linked to evolution of resistance to O3. In this study, we contrasted these responses to O3 in the presence of concurrent glyphosate pressure. The GR and GS biotypes differed in growth and injury, reflecting their known differential sensitivities to glyphosate, but responded similarly to O3 with no O3 × biotype interaction. Ozone imposed an unexpected, but ecologically important, impact that enhanced the performance advantage of GR over GS. In the presence of the combination of glyphosate and O3 the biomass of GR was reduced to low but viable levels, whereas the biomass of GS was reduced to nonviable levels that effectively removed it from the population. These data do not support a genetic linkage between resistance to glyphosate and to O3, but suggest that air pollution may have accelerated the fixation of glyphosate-resistance alleles in California horseweed populations.

Understanding the influence of solar variability on the Earth's climate requires knowledge of solar variability, solar-terrestrial interactions and observations, as well as mechanisms determining the response of the Earth's climate system. A summary of our current understanding from observational and modeling studies is presented with special focus on the “top-down” stratospheric UV and the “bottom-up” air-sea coupling mechanisms linking solar forcing and natural climate variability.

We have used data from the Ozone Monitoring Instrument (OMI) aboard NASA's Earth Observing System (EOS) Aura satellite over the period 2004–11 to describe the characteristics of surface ultraviolet (UV) irradiance at Escudero Station (62°12′S, 58°57′W). The station is located on King George Island (northern Antarctic Peninsula). Temperatures in summer are frequently above 0°C, and the surrounding ocean is typically ice-free. We found that the UV irradiance at Escudero is driven by the Antarctic ozone hole (which annually in spring leads to significant variations in the ozone) and by clouds (which are more frequent and have a larger optical depth compared with other Antarctic sites). The combined effect of ozone and clouds led to significant variations in the surface UV. The variability (taken as the standard deviation of the UV estimates retrieved from OMI) is typically greater than 30% at Escudero, but may reach values greater than 50% in spring. The consistency of OMI-derived data was checked by using ground-based spectral measurements carried out under controlled conditions in January 2011.

Peatland testate amoebae are widely used to reconstruct paleohydrological/climatic changes, but many species are also known to respond to pollutants. Peatlands around the world have been exposed to anthropogenic and intermittent natural pollution through the late Holocene. This raises the question: can pollution lead to changes in the testate amoeba paleoecological record that could be erroneously interpreted as a climatic change? To address this issue we applied testate amoeba transfer functions to the results of experiments adding pollutants (N, P, S, Pb, O3) to peatlands and similar ecosystems. We found a significant effect in only one case, an experiment in which N and P were added, suggesting that pollution-induced biases are limited. However, we caution researchers to be aware of this possibility when interpreting paleoecological records. Studies characterising the paleoecological response to pollution allow pollution impacts to be tracked and distinguished from climate change.

It is well established that the reaction of HO2 with NO plays a central role in atmospheric chemistry, by way of OH/HO2 recycling and reduction of ozone depletion by HOx cycles in the stratosphere and through ozone production in the troposphere. Utilizing a photochemical box model, we investigate the impact of the recently observed HNO3 production channel (HO2+NO → HNO3) on NOx (NO + NO2), HOx (OH + HO2), HNO3, and O3 concentrations in the boundary layer at the South Pole, Antarctica. Our simulations exemplify decreases in peak O3, NO, NO2, and OH and an increase in HNO3. Also, mean OH is in better agreement with observations, while worsening the agreement with O3, HO2, and HNO3 concentrations observed at the South Pole. The reduced concentrations of NOx are consistent with expected decreases in atmospheric NOx lifetime as a result of increased sequestration of NOx into HNO3. Although we show that the inclusion of the novel HNO3 production channel brings better agreement of OH with field measurements, the modelled ozone and HNO3 are worsened, and the changes in NOx lifetime imply that snowpack NOx emissions and snowpack nitrate recycling must be re-evaluated.

We estimate the consequences of a potential strong decrease of the solar activity using the model simulations of the future driven by pure anthropogenic forcing as well as its combination with different solar activity related factors: total solar irradiance, spectral solar irradiance, energetic electron precipitation, solar protons and galactic cosmic rays. The comparison of the model simulations shows that introduced strong decrease of solar activity can lead to some delay of the ozone recovery and partially compensate greenhouse warming acting in the direction opposite to anthropogenic effects. The model results also show that all considered solar forcings are important in different atmospheric layers and geographical regions. However, in the global scale the solar irradiance variability can be considered as the most important solar forcing. The obtained results constitute probably the upper limit of the possible solar influence. Development of the better constrained set of future solar forcings is necessary to address the problem of future climate and ozone layer with more confidence.

Gamma-ray bursts (GRBs) are likely to have made a number of significant impacts on the Earth during the last billion years. The gamma radiation from a burst within a few kiloparsecs would quickly deplete much of the Earth's protective ozone layer, allowing an increase in solar ultraviolet radiation reaching the surface. This radiation is harmful to life, damaging DNA and causing sunburn. In addition, NO2 produced in the atmosphere would cause a decrease in visible sunlight reaching the surface and could cause global cooling. Nitric acid rain could stress portions of the biosphere, but the increased nitrate deposition could be helpful to land plants. We have used a two-dimensional atmospheric model to investigate the effects on the Earth's atmosphere of GRBs delivering a range of fluences, at various latitudes, at the equinoxes and solstices, and at different times of day. We have estimated DNA damage levels caused by increased solar UVB radiation, reduction in solar visible light due to NO2 opacity, and deposition of nitrates through rainout of HNO3. In this paper we give a concise review of this work and discuss current and future work on extending and improving our estimates of the terrestrial impact of a GRB.

We propose that the photochemical smog mechanism produced substantial ozone (O3) in the troposphere during the Proterozoic period, which contributed to ultraviolet (UV) radiation shielding, and hence favoured the establishment of life. The smog mechanism is well established and is associated with pollution hazes that sometimes cover modern cities. The mechanism proceeds via the oxidation of volatile organic compounds such as methane (CH4) in the presence of UV radiation and nitrogen oxides (NOx). It would have been particularly favoured during the Proterozoic period given the high levels of CH4 (up to 1000 ppm) recently suggested. Proterozoic UV levels on the surface of the Earth were generally higher compared with today, which would also have favoured the mechanism. On the other hand, Proterozoic O2 required in the final step of the smog mechanism to form O3 was less abundant compared with present times. Furthermore, results are sensitive to Proterozoic NOx concentrations, which are challenging to predict, since they depend on uncertain quantities such as NOx source emissions and OH concentrations. We review NOx sources during the Proterozoic period and apply a photochemical box model having methane oxidation with NOx, HOx and Ox chemistry to estimate the O3 production from the smog mechanism. Runs suggest the smog mechanism during the Proterozoic period can produce approximately double the present-day ozone columns for NOx levels of 1.53×10−9 by volume mixing ratio, which was attainable according to our NOx source analysis, with 1% of the present atmospheric levels of O2. Clearly, forming ozone in the troposphere is a trade-off for survivability – on the one hand, harmful UV radiation is blocked, but on the other hand ozone is a respiratory irratant, which becomes fatal at concentrations exceeding about 1 ppmv.

Chemical pollutants, for example ozone, have been demonstrated to have detrimental effects on the cardiorespiratory system in human beings. Inhalation of pollutants may therefore impact on the performance of athletes at the 2004 Athens Olympic Games. Horses will also be exposed to these pollutants contained within the large volume of air they inhale during exercise. Opportunely, the equine events will be staged outside of Athens and as a result the concentration of atmospheric chemical pollutants is likely to be lower than that experienced by many of the human athletes. The horses' housing environment should also be carefully considered as a source of pollutants, as certain bedding materials can release dust, mould spores and irritants that may induce airway inflammation. In order to achieve the highest level of performance it is essential that both horse and rider be in good health and therefore the influence of environmental pollutants on lung function should to be minimized.

Ozone concentrations in the atmospheric surface layer above the Weddell Sea during the Antarctic spring season of 1989 varied significantly. Lower levels of ozone were associated with colder Antarctic air masses and higher values with warmer mid-latitude air. The lowest ozone concentration (1 to 2 ppbv) was measured in the centre of a low pressure system. A definite diurnal variation of tropospheric ozone observed during clear days with low total ozone amount (177 matm cm) may be interpreted as a consequence of the occurrence of photochemical reactions under conditions of increased ultraviolet solar radiation.