Abstract  The objective of this study was to examine the association between the levels of ozone concentration and emergency department (ED) visits for respiratory and cardiovascular conditions in Maryland in the United States by considering temporal and spatial characteristics, including socioeconomic status (SES), as a covariate. This study used multiple large datasets derived from government agencies for data of ozone, weather, census, and ED visits to represent Maryland in the summer of 2002. Block kriging was used to estimate the daily ozone and weather factors by ZIP code-day level. Results from a negative binomial regression showed that a 10-ppb increment of the 8-hr ozone level as a three-day average was associated with increased respiratory ED visits by 2.4%, after adjusting for weather factors, SES, and day of the week. For cardiovascular ED visits, an increment of 10 ppb of the 8-hr ozone level as a five-day average increased by 3.5%.

Abstract  The impact of air pollution on asthma in children in different age group has not been well defined. Objective: This study aimed to evaluate the association between seasonal variations in air pollution and asthma hospitalization of children within a two-year period.

Using the National Health Insurance database, seasonal variations in hospitalization trends in children with a primary diagnosis of asthma (International Classification of Disease 9th revision, code 493) for patients aged < 18 years from 2001 to 2002 were investigated. Data on the average concentration of nitrogen dioxide (NO(2)), carbon monoxide (CO), ozone(O(3)), sulphur dioxide (SO(2)), and particles with aerodynamic diameter < 10 microm (PM(10)) for each month were obtained from the Environmental Protection Department through 71 stations of air quality monitor distributed nationwide. PSI value (pollutants standard index)> 100 was considered poor air quality. Seasonal variations in asthma admissions were compared to the air pollution quality data using Spearman's rank correlation.

Asthma hospitalization was not related to the number of days when the PSI was > 100 during the 24-months period (r = -0.361; p = 0.083). However, it was significantly associated with seasonal changes in the concentration of each pollutant. The most strongly related air pollutant variable was PM(10) (standardized coefficients 0.384), followed by 0(3) (standardized coefficients 0.255) and SO(2) (standardized coefficients 0.162) concentrations. The association of seasonal changes in asthma hospitalization with these pollutants was greater in pre-school and school age children. Temperature and rainfall in all seasons were not related to asthma hospitalization. None of the pollutants were associated with seasonal variations in admission rate for adolescents.

Seasonal variations of asthma hospitalization among preschool children are associated with concentration of air pollutants.

Abstract  The association of air pollutants with natural and respiratory mortality has been consistently reported. However, several aspects of the relationship between particles with an aerodynamic diameter of less than 10 micrometers (PM10) and respiratory mortality require further investigation. To assess the PM10 - respiratory mortality association in Italy and to examine potentially susceptible groups. All natural (n. 276,205) and respiratory deaths (n. 19,629) occurring among 35-plus-year-olds in ten northern, central and southern Italian cities in 2001-2005 were selected. Data for 10-micron particulate matter, nitrogen dioxide and ozone were obtained. A time-stratified case-crossover analysis was carried out. Different cumulative lags were selected to analyse immediate, delayed, prolonged and best-time effects of air pollution. The shape of the exposure-response relationship was analysed. Age, gender, chronic conditions and death site were investigated as potential effect modifiers. We found a 2.29% (IC95%=1.03; 3.58) increase in respiratory mortality at 0-3 lags. The increase in respiratory mortality was higher in summer (7.57%). The exposure-response curve had a linear shape without any threshold. Gender and chronic diseases modified the relationship between particulate matter and respiratory mortality. The effect of particulate on respiratory mortality was stronger and more persistent than that on natural mortality. Females and chronic disease sufferers were more likely to die of a respiratory disease caused by air pollution than males and healthy people.

Abstract  Studies show that ambient temperature and air pollution are associated with cardiovascular disease and that they may interact to affect cardiovascular events. However, few epidemiologic studies have examined mechanisms through which ambient temperature may influence cardiovascular function. The authors examined whether temperature was associated with heart rate variability (HRV) in a Boston, Massachusetts, study population and whether such associations were modified by ambient air pollution concentrations. The population was a cohort of 694 older men examined between 2000 and 2008. The authors fitted a mixed model to examine associations between temperature and air pollution and their interactions with repeated HRV measurements, adjusting for covariates selected a priori on the basis of their previous studies. Results showed that higher ambient temperature was associated with decreases in HRV measures (standard deviation of normal-to-normal intervals, low-frequency power, and high-frequency power) during the warm season but not during the cold season. These warm-season associations were significantly greater when ambient ozone levels were higher (>22.3 ppb) but did not differ according to levels of ambient fine (≤2.5 μm) particulate matter. The authors conclude that temperature and ozone, exposures to both of which are expected to increase with climate change, might act together to worsen cardiovascular health and/or precipitate cardiovascular events via autonomic nervous system dysfunction.

Abstract  Little is known about the levels of air pollution at public parks where regular exercise takes place or in park-adjacent neighborhoods where people have easy access to parks. In this study we investigated the ambient concentrations of criteria pollutants nitrogen dioxide (NO(2)), fine particulate (PM(2.5)) and ozone (O(3)) at public parks and in park-adjacent neighborhoods for metropolitan Los Angeles. Socioeconomic and racial-ethnic inequalities in exposure to the three criteria pollutants were also investigated using multiple linear regression models. In addition, differences in inhalation doses from breathing the three +criteria pollutants were investigated for the top and bottom quartile racial composition in the parks and neighborhoods. Our research showed that although public parks had on average the lowest pollutant concentrations of NO(2) and PM(2.5), they had relatively high O(3) concentrations. Park-adjacent neighborhoods, by contrast, had the highest NO(2) and PM(2.5) concentrations, but the lowest O(3) concentrations. Higher exposures to NO(2) and PM(2.5) were systematically identified for the lower socioeconomic position or higher minority population neighborhoods. For children and adolescents aged 6-15 engaging in high and moderate intensity activities in and around public parks, those from the top quartile of primarily Hispanic neighborhoods had much higher (63%) inhaled doses of NO(2) compared to the bottom quartile counterpart. PM(2.5) showed a similar but less pronounced pattern of inhalation doses. Evidence of socioeconomic and racial-ethnic gradients was found in air pollution exposure and inhalation doses in and around the urban parks in Los Angeles. This suggests that patterns of exposure inequality found in other environmental justice research are present in exposures in and around urban parks.

Abstract  In the two decades since the first issue of Indoor Air, there have been over 250 peer-reviewed publications addressing chemical reactions among indoor pollutants. The present review has assembled and categorized these publications. It begins with a brief account of the state of our knowledge in 1991 regarding 'indoor chemistry', much of which came from corrosion and art conservation studies. It then outlines what we have learned in the period between 1991 and 2010 in the context of the major reference categories: gas-phase chemistry, surface chemistry, health effects and reviews/workshops. The indoor reactions that have received the greatest attention are those involving ozone-with terpenoids in the gas-phase as well as with the surfaces of common materials, furnishings, and the occupants themselves. It has become clear that surface reactions often have a larger impact on indoor settings than do gas-phase processes. This review concludes with a subjective list of major research needs going forward, including more information on the decomposition of common indoor pollutants, better understanding of how sorbed water influences surface reactions, and further identification of short-lived products of indoor chemistry. Arguably, the greatest need is for increased knowledge regarding the impact that indoor chemistry has on the health and comfort of building occupants. PRACTICAL IMPLICATIONS: Indoor chemistry changes the type and concentration of chemicals present in indoor environments. In the past, products of indoor chemistry were often overlooked, reflecting a focus on stable, relatively non-polar organic compounds coupled with the use of sampling and analytical methods that were unable to 'see' many of the products of such chemistry. Today, researchers who study indoor environments are more aware of the potential for chemistry to occur. Awareness is valuable, because it leads to the use of sampling methods and analytical tools that can detect changes in indoor environments resulting from chemical processes. This, in turn, leads to a more complete understanding of occupants' chemical exposures, potential links between these exposures and adverse health effects and, finally, steps that might be taken to mitigate these adverse effects.

Abstract  Two Euro 3 commercial trucks fuelled with a 30% v/v biodiesel/diesel fuel blend (B30) and pure diesel fuel were tested in laboratory under the standard driving conditions (UDC and EUDC driving cycles) and the CADC "URBAN" test cycle, in order to evaluate the fuel consumption, regulated (CO, HC, NOR, PM) and unregulated emissions (aldehydes and polycyclic aromatic hydrocarbons). After substitution of diesel fuel with B30 the following results were observed. The fuel economy increased proportionally to the deficit of the fuel heating value; so the average efficiency of the engine can be considered almost unchanged. In partial disagreement with the literature data, CO and HC emissions showed a slight increase, whereas NO(x) emissions did not vary. It must be noted that these variations did not pass the statistical significance test. On the contrary, PM, soot fraction and particle number showed a significant reduction; furthermore, nearly 90% of the emitted particles had an aerodynamic diameter less than 0.1 mu m. The formaldehyde emission markedly increased for both vehicles, whereas acetaldehyde emissions showed ambiguous trends. Since the remaining aldehydes were under the instrumental detection limit, the ozone formation potential analysis with B30 showed a raise almost proportional to the formaldehyde emission increase. Moreover the lightest and most abundant PAHs species (3-4 benzene rings) showed high increases even if to different extent for the two vehicles. The species with 4-5 rings (such as benzo(a)pyrene) showed a net reduction, often under the instrumental limit. Finally, the carcinogenic risk evaluation of PAHs exhibited a clear toxicity reduction, specially in the cold start cycle, when the catalytic converter's efficiency was not fully reached. (C) 2011 Elsevier Ltd. All rights reserved.

Abstract  Hydrogen is named as possible energy carrier for future energy systems. However, the impact of large-scale hydrogen use on the atmosphere is uncertain. Application of hydrogen in clean fuel cells reduces emissions of air pollutants, but emissions from hydrogen production and leakages of molecular hydrogen could influence atmospheric chemistry. This paper combines a global energy system model and a global atmospheric model to explore the range of impacts of hydrogen on atmospheric chemistry. We found that emissions of molecular hydrogen may range from 0.2 up to 10% (or 25–167Tg hydrogen/yr) for a global hydrogen energy system. The lower end of this range would in fact be equal to current emissions from fossil fuel combustion. Hydrogen energy use leads to a clear decrease in emissions of carbon monoxide, nitrogen oxides and sulphur dioxide, but large-scale hydrogen production from coal may lead to net increase in emissions of nitrous oxide and volatile organic compound. Compared to a reference scenario, this would lead to positive impacts on surface concentrations of carbon monoxide, nitrogen oxides and ozone. However, if hydrogen leakage would not be minimised it leads to an increase in methane lifetimes and a decrease in stratospheric ozone concentrations.

Abstract  Environmental policies in Europe have successfully eliminated the most visible and immediate harmful effects of air pollution in the last decades. However, there is ample and robust scientific evidence that even at present rates Europe’s emissions to the atmosphere pose a significant threat to human health, ecosystems and the global climate, though in a less visible and immediate way. As many of the ‘low hanging fruits’ have been harvested by now, further action will place higher demands on economic resources, especially at a time when resources are strained by an economic crisis. In addition, interactions and interdependencies of the various measures could even lead to counter-productive outcomes of strategies if they are ignored. Integrated assessment models, such as the GAINS (Greenhouse gas – Air pollution Interactions and Synergies) model, have been developed to identify portfolios of measures that improve air quality and reduce greenhouse gas emissions at least cost. Such models bring together scientific knowledge and quality-controlled data on future socio-economic driving forces of emissions, on the technical and economic features of the available emission control options, on the chemical transformation and dispersion of pollutants in the atmosphere, and the resulting impacts on human health and the environment. The GAINS model and its predecessor have been used to inform the key negotiations on air pollution control agreements in Europe during the last two decades. This paper describes the methodological approach of the GAINS model and its components. It presents a recent policy analysis that explores the likely future development of emissions and air quality in Europe in the absence of further policy measures, and assesses the potential and costs for further environmental improvements. To inform the forthcoming negotiations on the revision of the Gothenburg Protocol of the Convention on Long-range Transboundary Air Pollution, the paper discusses the implications of alternative formulations of environmental policy targets on a cost-effective allocation of further mitigation measures.

Abstract  Self-reported data on the municipality of residence were used to assess long-term exposure to outdoor air pollution from 1980 to 2002 in the longitudinal Canadian National Population Health Survey. Exposure to carbon monoxide, nitrogen dioxide, ozone, sulfur dioxide, and particulate matter was determined using data obtained from fixed-site air pollution monitors operated principally in urban areas. Four different methods of attributing pollution exposure were used based on residence in (1) 1980, (2) 1994, (3) 1980 and 1994, and (4) at all locations between 1980 and 2002. Between 1,693 and 4,274 of 10,515 members of the cohort could be assigned exposures to individual pollutants using these methods. On average, subjects spent 71.4% of the 1980-2002 period in the census subdivision where they lived in 1980. A single exposure measure in 1980 or 1994 or a mean of the two measures was highly correlated (r>0.7, P<0.0001) with a measure which accounted for all moves between 1980 and 2002. Although our ability to characterize long-term exposure was constrained by a lack of data from fixed-site monitors, the low frequency of moves meant that measures based on a single year generally provided a good approximation of long-term exposure at the census subdivision level.

Abstract  The reactive uptake coefficients (γ) of O(3), NO(2), N(2)O(5), and NO(3) by levoglucosan, abietic acid, nitroguaiacol, and an atmospherically relevant mixture of those species serving as surrogates for biomass burning aerosol have been determined employing a chemical ionization mass spectrometer coupled to a rotating-wall flow-tube reactor. γ of O(3), NO(2), N(2)O(5), and NO(3) in the presence of O(2) are in the range of 1-8 × 10(-5), <10(-6)-5 × 10(-5), 4-6 × 10(-5), and 1-26 × 10(-3), respectively, for the investigated organic substrates. Within experimental uncertainties the uptake of NO(3) was not sensitive to relative humidity levels of 30 and 60%. NO(3) uptake experiments involving substrates of levoglucosan, abietic acid, and the mixture exhibit an initial strong uptake of NO(3) followed by NO(3) gas-phase recovery as a function of NO(3) exposure. In contrast, the uptake of NO(3) by nitroguaiacol continuously proceeds at the same efficiency for investigated NO(3) exposures. The derived oxidative power, i.e. the product of γ and atmospheric oxidant concentration, for applied oxidants is similar or significantly larger in magnitude than for OH, emphasizing the potential importance of these oxidants for particle oxidation. Estimated atmospheric lifetimes for the topmost organic layer with respect to O(3), NO(2), N(2)O(5), and NO(3) oxidation for typical polluted conditions range between 1-112 min, indicating the potential for significant chemical transformation during atmospheric transport. The contact angles determined prior to, and after heterogeneous oxidation by NO(3), representative of 50 ppt for 1 day, do not decrease and thus do not indicate a significant increase in hygroscopicity with potential impacts on water uptake and cloud formation processes.

Abstract  A general overview on the prospective of various oxidation and combined processes in the treatment of tannery industry effluent are reported. Various oxidation and combined processes such as UV/H2O2/Hypochlorites, Fenton and Electro-oxidation, photo-chemical, photo-catalytic, electro-catalytic oxidation, wet air oxidation, ozonation, biological followed by ozone/UV/H2O2, coagulation or electro-coagulation and catalytic treatments have been considered. The tannery wastewater with sulphide as main sources of pollutant, electro-coagulation is the best removal efficiency process among the other oxidation processes, whereas for chromium, photo catalytic oxidation process using nano-TiO2 and wet air oxidation in the presence of manganese sulphate and activated carbon as a catalyst are more efficiency processes. The integrated combined processes described permit to meet disposal limits, health quality standards and the recovery of several chemicals utilized in the tanneries.

Abstract  Plant-derived phenylpropanoids (PPPs) compose the largest group of secondary metabolites produced by higher plants, mainly, for the protection against biotic or abiotic stresses such as infections, wounding, UV irradiation, exposure to ozone, pollutants, and herbivores. PPPs are parent molecules for biosynthesis of numerous structurally and functionally diverse plant polyphenols (simple phenolic acids and esters, glycosylated derivatives of primary PPPs, flavonoids, isoflavonoids, stilbenes, coumarins, curcuminoids, lignans, etc.), which play multiple essential roles in plant physiology. During the last few decades, extensive research has been dedicated to natural and biotechnologically produced PPPs for medicinal use as antioxidants, UV screens, anticancer, antiviral, anti-inflammatory, wound healing, and antibacterial agents. In the present review, the metabolic pathways of phenylpropanoid biosynthesis in plants and their re-construction in biotechnologically engineered systems are described. Chemical physical peculiarities of PPPs defining their antioxidant, metal chelating, and UV-protecting effects as a molecular basis for their anti-inflammatory properties are discussed as well. We focused also on the discovery of PPPs-based anti-inflammatory agents since distinct PPPs were found to modulate molecular pathways underlying inflammatory responses in human cells triggered by different pro-inflammatory stimuli in vitro and to inhibit inflammation in various tissues in vivo. The problem of low bioavailability, fast metabolism, and potential toxicity/sensitization as limiting factors for the development of PPPs-based anti-inflammatory drugs is also highlighted.

Abstract  Food consumption causes, together with mobility, shelter and the use of electrical products, most life cycle impacts of consumption. Meat and dairy are among the highest contributors to environmental impacts from food consumption. A healthier diet might have less environmental impacts. Using the E3IOT environmentally extended input output database developed in an EU study on Environmental Impacts of Products (EIPRO), this paper estimates the difference in impacts between the European status quo and three simulated diet baskets, i.e. a pattern according to universal dietary recommendations, the same pattern with reduced meat consumption, and a 'Mediterranean' pattern with reduced meat consumption. Production technologies, protein and energy intake were kept constant. Though this implies just moderate dietary shifts, impact reductions of up to 8% were possible in reduced meat scenarios. The slightly changed food costs do not lead to significant first order rebound effects. Second order rebounds were estimated by applying the CAPRI partial equilibrium model. This analysis showed that European meat production sector will most likely respond by higher exports to compensate for losses on the domestic meat market. Higher impact reductions probably would need more drastic diet changes. (C) 2011 Elsevier B.V. All rights reserved.

Abstract  The volatile organic compound isoprene is produced by many plant species, and provides protection against biotic and abiotic stresses1. Globally, isoprene emissions from plants are estimated to far exceed anthropogenic emissions of volatile organic compounds2. Once in the atmosphere, isoprene reacts rapidly with hydroxyl radicals3 to form peroxy radicals, which can react with nitrogen oxides to form ground-level ozone4. Here, we use canopy-scale measurements of isoprene fluxes from two tropical ecosystems in Malaysia—a rainforest and an oil palm plantation—and three models of atmospheric chemistry to explore the effects of isoprene fluxes on ground-level ozone. We show that isoprene emissions in these ecosystems are under circadian control on the canopy scale, particularly in the oil palm plantation. As a result, these ecosystems emit less isoprene than present emissions models predict. Using local-, regional- and global-scale models of atmospheric chemistry and transport, we show that accounting for circadian control of isoprene emissions brings model predictions of ground-level ozone into better agreement with measurements, especially in isoprene-sensitive regions of the world.

Abstract  Both classical and Berkson exposure measurement errors as encountered in environmental epidemiology data can result in biases in fitted exposure-response relationships that are large enough to affect the interpretation and use of the apparent exposure-response shapes in risk assessment applications. A variety of sources of potential measurement error exist in the process of estimating individual exposures to environmental contaminants, and the authors review the evaluation in the literature of the magnitudes and patterns of exposure measurement errors that prevail in actual practice. It is well known among statisticians that random errors in the values of independent variables (such as exposure in exposure-response curves) may tend to bias regression results. For increasing curves, this effect tends to flatten and apparently linearize what is in truth a steeper and perhaps more curvilinear or even threshold-bearing relationship. The degree of bias is tied to the magnitude of the measurement error in the independent variables. It has been shown that the degree of bias known to apply to actual studies is sufficient to produce a false linear result, and that although nonparametric smoothing and other error-mitigating techniques may assist in identifying a threshold, they do not guarantee detection of a threshold. The consequences of this could be great, as it could lead to a misallocation of resources towards regulations that do not offer any benefit to public health.

Abstract  Susceptibility to the respiratory effects of air pollution varies between individuals. Although some evidence suggests higher susceptibility for subjects carrying variants of antioxidant genes, findings from gene-pollution interaction studies conflict in terms of the presence and direction of interactions. The authors conducted a systematic review on antioxidant gene-pollution interactions which included 15 studies, with 12 supporting the presence of interactions. For the glutathione S-transferase M1 gene (GSTM1) (n = 10 studies), only 1 study found interaction with the null genotype alone, although 5 observed interactions when GSTM1 was evaluated jointly with other genes (mainly NAD(P)H dehydrogenase [quinone] 1 (NQO1)). All studies on the glutathione S-transferase P1 (GSTP1) Ile105Val polymorphism (n = 11) provided some evidence of interaction, but findings conflicted in terms of risk allele. Results were negative for glutathione S-transferase T1 (GSTT1) (n = 3) and positive for heme oxygenase 1 (HMOX-1) (n = 2). Meta-analysis could not be performed because there were insufficient data available for any specific gene-pollutant-outcome combination. Overall the evidence supports the presence of gene-pollution interactions, although which pollutant interacts with which gene is unclear. However, issues regarding multiple testing, selective reporting, and publication bias raise the possibility of false-positive findings. Larger studies with greater accuracy of pollution assessment and improved quality of conduct and reporting are required.

Abstract  Policies to control emissions of criteria pollutants in China may have conflicting impacts on public health, soil acidification, and climate. Two scenarios for 2020, a base case without anticipated control measures and a more realistic case including such controls, are evaluated to quantify the effects of the policies on emissions and resulting environmental outcomes. Large benefits to public health can be expected from the controls, attributed mainly to reduced emissions of primary PM and gaseous PM precursors, and thus lower ambient concentrations of PM2.5. Approximately 4% of all-cause mortality in the country can be avoided (95% confidence interval: 1-7%), particularly in eastern and north-central China, regions with large population densities and high levels of PM2.5. Surface ozone levels, however, are estimated to increase in parts of those regions, despite NOX reductions. This implies VOC-limited conditions. Even with significant reduction of SO2 and NOX emissions, the controls will not significantly mitigate risks of soil acidification, judged by the exceedance levels of critical load (CL). This is due to the decrease in primary PM emissions, with the consequent reduction in deposition of alkaline base cations. Compared to 2005, even larger CL exceedances are found for both scenarios in 2020, implying that PM control may negate any recovery from soil acidification due to SO2 reductions. Noting large uncertainties, current polices to control emissions of criteria pollutants in China will not reduce climate warming, since controlling SO2 emissions also reduces reflective secondary aerosols. Black carbon emission is an important source of uncertainty concerning the effects of Chinese control policies on global temperature change. Given these conflicts, greater consideration should be paid to reconciling varied environmental objectives, and emission control strategies should target not only criteria pollutants but also species such as VOCs and CO2.

Abstract  The reaction products and pathways of protein nitration were studied with bovine serum albumin (BSA) and ovalbumin (OVA) nitrated by liquid tetranitromethane (TNM) or by gaseous nitrogen dioxide and ozone (NO(2)+O(3)). Native and nitrated proteins were enzymatically digested with trypsin, and the tryptic peptides were analyzed by high-performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS) using a chip cube nano-flow system (Agilent). Upon nitration by TNM, up to ten of 17 tyrosine residues in BSA and up to five of ten tyrosine residues in OVA could be detected in nitrated form. Upon nitration by NO(2)+O(3), only three nitrated tyrosine residues were found in BSA. The nitration degrees of individual nitrotyrosine residues (ND(Y)) were determined by site-specific quantification and compared to the total protein nitration degrees (ND) determined by photometric detection of HPLC-DAD. The slopes of the observed linear correlations between ND(Y) and ND varied in the range of ~0.02-2.4 for BSA and ~0.2-1.6 for OVA. They provide information about the relative rates of nitration or reaction probabilities for different tyrosine residues. In BSA, the tyrosine residue Y(161) was by far most reactive against NO(2)+O(3) and one of the four most reactive positions with regard to nitration by TNM. In OVA, all except one tyrosine residue detected in nitrated form exhibited similar reactivities. The observed nitration patterns show how the site selectivity of protein nitration depends on the nitrating agent, reaction conditions, and molecular structure of the protein (primary, secondary, and tertiary).

Abstract  The negative impacts of surface ozone (O3) on vegetation are determined by external exposure, leaf gas exchange and plant antioxidant defence capacity, all dependent on climate and CO2 concentrations. In this study the influence of climate change on simulated stomatal O3 uptake of a generic crop and a generic deciduous tree at ten European sites was investigated, using the LRTAP Mapping Manual stomatal flux model. O3 concentrations are calculated by a chemistry transport model (MATCH) for three 30‐yr time‐windows (1961–1990, 2021–2050, 2071–2100), with constant precursor emissions and meteorology from a regional climate model (RCA3). Despite substantially increased modelled future O3 concentrations in central and southern Europe, the flux‐based risk for O3 damage to vegetation is predicted to remain unchanged or decrease at most sites, mainly as a result of projected reductions in stomatal conductance under rising CO2 concentrations. Drier conditions in southern Europe are also important for this result. At northern latitudes, the current parameterisation of the stomatal conductance model suggest O3 uptake to be mainly limited by temperature. This study demonstrates the importance of accounting for the influences by climate and CO2 on stomatal O3 uptake, and of developing their representation in models, for risk assessment involving climate change.

Abstract  Tropospheric ozone concentrations are increasing, which may result in elevated background concentrations at rural high-altitude sites. In this study simulated upland grassland communities containing seven species were exposed to ozone treatments in solardomes for 12 weeks in each of two consecutive summers. Ozone profiles, based on future ozone predictions, were of elevated background concentrations, episodic peaks of ozone and a combination of the two. During the winter between the two exposures the communities were kept outdoors in ambient air. Whereas previous studies have demonstrated that peaks of ozone cause detrimental effects to vegetation, this study shows that for simulated grassland communities an increase in background ozone concentration in the absence of peaks of ozone also corresponded with increased senescence. In many cases senescence was further increased when peaks of ozone were also present. The species used showed no acclimation to ozone and the same relationship between senescence and ozone dose occurred in both years of the study. A decrease in cumulative biomass was demonstrated for Anthoxanthum odoratum, which contributed to a decrease in total community biomass and grass:forb ratio. These results indicate that current and future ozone concentrations could cause detrimental effects on growth and vitality of natural grassland communities and that for some species the consequences of increased background ozone concentration are as severe as that of increased peaks.

Abstract  We present here the effects of ambient ozone (O(3))-induced decline in carbon availability, accelerated foliar senescence, and a decrease in aboveground biomass accumulation in the Aleppo pine (Pinus halepensis Mill.). Aleppo pine seedlings were continuously exposed in open-top chambers for 39 months to three different types of O(3) treatments, which are as follows: charcoal-filtered air, nonfiltered air (NFA), and nonfiltered air supplemented with 40 ppb O(3) (NFA+). Stable carbon isotope discrimination (Delta) and derived time-integrated c (i)/c (a) ratios were reduced after an accumulated ozone exposure over a threshold of 40 ppb (AOT40) value from April to September of around 20,000 ppb center dot h. An AOT40 of above 67,000 ppb center dot h induced reductions in ribulose-1,5-biphosphate carboxylase/oxygenase activity, aboveground C and needle N and K concentrations, the C/N ratio, Ca concentrations in twigs under 3 mm, and the aerial biomass, as well as increases in needle P concentrations and phosphoenolpyruvate carboxylase (PEPC) activity and the N and K concentrations in twigs under 3 mm. Macronutrients losses, the limitations placed on carbon uptake, and increases in catabolic processes may be the causes of carbon gain diminution in leaves which was reflected as a reduction in aboveground biomass at tree level. Stimulation of PEPC activity, the consequent decreased Delta, and compensation processes in nutrient distribution may increase O(3) tolerance and might be interpreted as part of Aleppo pine acclimation response to O(3).

Abstract  Five-month-old male rates were exposed to 0.5 ppm ozone for 50 days, 5 hours a day. A week before the completion of ozone exposure, a biological test was performed to determine the fertilization rate and the survival rate of newborns in both ozone-exposed and control animals. After 50 days, the rats were sacrificed with an overdose of halotane, and testes were collected to assess the morphology and motility of spermatozoa. Neither the morphology of spermatozoa nor motility parameters determined by the CASA (computer-assisted sperm analysis) system showed statistically significant differences between ozone-exposed and control males. The number of successful matings and the survival rate of newborns per litter within one year postpartum were also similar in both groups. However, sperm concentration was by 17% lower in ozone-exposed rats, compared with the control animals.

Abstract  Abstract: For several years several vehicle emission control technologies have been developed and introduced to reduce the contribution of road traffic to air pollution. However, this contribution in the Île de France region, around Paris, France, has been estimated to still be significant. We present a modeling study of the effect of the future evolution of traffic emissions on air quality at the urban scale. The aim is to assess the respective contribution of the different processes involved in the nonlinear chemistry of photochemical air pollution (change in emissions and/or chemical behaviour) that explain the observed evolution of concentrations of traffic-related pollutants at monitoring urban background stations. The modeling results suggest that the reduction of NO _x emissions must be coupled with more stringent measures on NMVOC emissions than those currently planned in the transportation sector to avoid an increase of O₃ concentrations in some densely populated areas. The modeled NO₂ concentrations in Paris reach a maximum in 2010 due to an increase of the NO₂ emissions related to the evolution of the NO₂/NO _x ratio of the Diesel vehicle emissions. The reduction of PM emissions leads to a non-proportional decrease in PM concentrations, which results mostly from the decrease in Diesel particulate emissions.

Abstract  Elevated levels of ambient co-pollutants are associated with adverse cardiovascular outcomes shown by epidemiology studies. The role of particulate matter (PM) and ozone (O3) as co-pollutants in this association is unclear. We hypothesize that cardiac function following PM and O3 exposure is variably affected by genetic determinants (Nppa and Npr1 genes) and age. Heart function was measured before and after 2 days each of the following exposure sequence; (1) 2-h filtered air (FA) and 3-h carbon black (CB; 0.5 µg/m3); (2) 2-h O3 (0.6ppm) and 3-h FA; (3) 5-h FA; and, (4) 2-h O3 and 3-h CB. Two age groups (5 and 18 months old (mo)) were tested in C57Bl/6J (B6) and 129S1/SvImJ (129) mice using echocardiographic (echo) and in vivo hemodynamic (IVH) measurements. With echo, posterior wall thickness was significantly (P<0.01) greater in 129 relative to B6 mice at baseline. With CB exposure, young B6 and older 129 mice show significant (P<0.01) reductions in fractional shortening (FS) compared to FA. With O3 exposure, FS was significantly (P<0.01) diminished in young 129, which was attributable to significant increases in end-systolic left ventricular diameter. With O3 and CB combined, notable (P<0.01) declines in heart rate and end-systolic posterior wall thickness occurred in young 129 mice. The IVH measurements showed striking (P<0.05) compromises in cardiac function after CB and O3 exposure; however, strain differences were undetectable. These results suggest that PM and O3 exposures, alone and combined, lead to different cardiac functional changes, and these unique changes are age-specific and dependent on Nppa and Npr1 genes.