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Introduction: The health effects of ambient ozone have been investigated in many previous studies. However, the effects of long-term exposure to ambient ozone on the incidence of cardiovascular disease (CVD) remain inconclusive. Objectives: To estimate the associations of long-term exposure to maximum daily 8-hours average ozone (MDA8 O3) with the incidence of total CVD, heart disease, hypertension, and stroke. Methods: This was a prospective cohort study, and the data was obtained from the China Health and Retirement Longitudinal Survey (CHARLS) implemented during 2011–2018 and the China Family Panel Studies (CFPS) implemented during 2010–2018. We applied a Cox proportional hazards regression model to evaluate the associations of MDA8 O3 with total CVD, heart disease, hypertension, and stroke risks, and the corresponding population-attributable fractions (PAF) attributable to MDA8 O3 were also calculated. All analyses were conducted by R software. Results: The mean MDA8 O3 concertation of all included participants in the CHARLS and CFPS were 51.03 part per billion (ppb) and 51.15 ppb, respectively. In the CHARLS including 18,177 participants, each 10 ppb increment in MDA8 O3 concentration was associated with a 31% increase [hazard ratio (HR) = 1.31, 95% confidence interval (CI): 1.22–1.42] in the risk of incident heart disease, and the corresponding population-attributable fractions (PAF) was 13.79% [10.12%-17.32%]. In the CFPS including 30,226 participants, each 10 ppb increment in MDA8 O3 concentration was associated with an increase in the risk of incident total CVD (1.07 [1.02–1.13]), and hypertension (1.10 [1.03–1.18]). The PAFs of total CVD, and hypertension attributable to MDA8 O3 were 3.53% [0.82%-6.16%], and 5.11% [1.73%-8.38%], respectively. Stratified analyses showed greater associations in males, urban areas, and Southern China. Conclusions: Long-term exposure to MDA8 O3 may increase the incidence of CVD. Therefore, the policies that control O3 and related precursors are persistently needed.

[Display omitted] • First cohort study in China to investigate long-term ambient O 3 exposure and CVD. • MDA8 O 3 may increase the risk of total CVD, heart disease and hypertension. • Effects of MDA8 O 3 were greater in males, urban areas, and Southern China. • We also provided the PAFs of CVD attributable to MDA8 O 3. • This study extended our understanding of chronic health effects of ambient O 3. The health effects of ambient ozone have been investigated in many previous studies. However, the effects of long-term exposure to ambient ozone on the incidence of cardiovascular disease (CVD) remain inconclusive. To estimate the associations of long-term exposure to maximum daily 8-hours average ozone (MDA8 O 3) with the incidence of total CVD, heart disease, hypertension, and stroke. This was a prospective cohort study, and the data was obtained from the China Health and Retirement Longitudinal Survey (CHARLS) implemented during 2011–2018 and the China Family Panel Studies (CFPS) implemented during 2010–2018. We applied a Cox proportional hazards regression model to evaluate the associations of MDA8 O 3 with total CVD, heart disease, hypertension, and stroke risks, and the corresponding population-attributable fractions (PAF) attributable to MDA8 O 3 were also calculated. All analyses were conducted by R software. The mean MDA8 O 3 concertation of all included participants in the CHARLS and CFPS were 51.03 part per billion (ppb) and 51.15 ppb, respectively. In the CHARLS including 18,177 participants, each 10 ppb increment in MDA8 O 3 concentration was associated with a 31% increase [hazard ratio (HR) = 1.31, 95% confidence interval (CI): 1.22–1.42] in the risk of incident heart disease, and the corresponding population-attributable fractions (PAF) was 13.79% [10.12%-17.32%]. In the CFPS including 30,226 participants, each 10 ppb increment in MDA8 O 3 concentration was associated with an increase in the risk of incident total CVD (1.07 [1.02–1.13]), and hypertension (1.10 [1.03–1.18]). The PAFs of total CVD, and hypertension attributable to MDA8 O 3 were 3.53% [0.82%-6.16%], and 5.11% [1.73%-8.38%], respectively. Stratified analyses showed greater associations in males, urban areas, and Southern China. Long-term exposure to MDA8 O 3 may increase the incidence of CVD. Therefore, the policies that control O 3 and related precursors are persistently needed. [ABSTRACT FROM AUTHOR]

Background: Although the health impacts of ambient ozone (O3) have been widely assessed, studies simultaneously investigating the acute and chronic effects of O3 on mortality from respiratory diseases (RESP) are scarce. Methods: We extracted personal information of all recorded deaths from RESP throughout 2013–2018 in six provinces in China. The daily, seasonal, and annual mean air pollutant concentrations at the township/subdistrict level were estimated by a random forest model. The acute association between the maximum daily average 8h ozone (MDA8 O3) and RESP mortality was examined by a time-stratified case-crossover study design, and the chronic association was estimated by a difference-in-differences (DID) analysis approach. We also calculated the attributable fraction (AF) of RESP mortality attributable to MDA8 O3. Results: There were 1,034,226 RESP deaths included in this study. The excess risks (ERs) of overall RESP mortality for each 10 μg/m3 increase in short-term (lag03 days) and long-term (one-year average) exposure to MDA8 O3 were 0.38 % (95%CI: 0.26 %, 0.50 %) and 4.37 % (3.91 %, 4.84 %), respectively. The AFs of overall RESP mortality ascribed to short- and long-term MDA8 O3 exposures were 3.00 % (2.03 %, 3.95 %) and 29.45 % (26.86 %, 31.95 %), respectively. The average annual number of RESP deaths attributable to short-term MDA8 O3 exposure was 30,790 and 302,254 were attributable to long-term MDA8 O3 exposure across China during 2013–2018. Conclusion: Both short- and long-term exposure to ambient MDA8 O3 were positively associated with RESP mortality, and long-term exposure to MDA8 O3 may lead to a greater RESP mortality burden than short-term exposure to MDA8 O3.

To date, the relationship between conjunctivitis and air pollutants has been widely concerned, but the conclusions are not very unified. This study aims to explore the short-term effects of ambient ozone (O3) on the conjunctivitis outpatient visits in Pudong New Area, Shanghai. A quasi-Poisson model combined with the distributed lag nonlinear model (DLNM) was performed to study the short-term effects of O3 on the risk of outpatient visits for conjunctivitis, after controlling the effects of temperature, relative humidity and wind speed. Taking the median concentration of O3 as a reference, the moderate high O3 (75th percentile) showed the largest effect estimates for single and cumulative lag effects at lag 4 (RR 1.013, 95% confidence interval [CI] 1.006–1.019) and lag 0–10 (RR 1.075, 95%CI 1.025–1.128), respectively. Our study suggested that the moderate high O3 increased the chances of conjunctivitis outpatient visits and had an evident lag effect. [ABSTRACT FROM AUTHOR]

Background: Epidemiological studies suggest that both ambient ozone (O3) and temperature were associated with increased risks of adverse birth outcomes. However, very few studies explored their interaction effects, especially for small for gestational age (SGA) and large for gestational age (LGA). Objectives: To estimate the modification effects of ambient temperature on associations of ambient O3 exposure before and during pregnancy with preterm birth (PTB), low birth weight (LBW), SGA and LGA based on multicity birth cohorts. Methods: A total of 56,905 singleton pregnant women from three birth cohorts conducted in Tianjin, Beijing and Maoming, China, were included in the study. Maximum daily 8-h average O3 concentrations of each pregnant woman from the preconception period to delivery for every day were estimated by matching their home addresses with the Tracking Air Pollution in China (TAP) datasets. We first applied the Cox proportional-hazards regression model to evaluate the city-specific effects of O3 exposure before and during pregnancy on adverse birth outcomes at different temperature levels with adjustment for potential confounders, and then a meta-analysis across three birth cohorts was conducted to calculate the pooled associations. Results: In pooled analysis, significant modification effects of ambient temperature on associations of ambient O3 with PTB, LBW and LGA were observed (Pinteraction 75th percentile), the risk of LBW increased by 28 % (HR: 1.28, 95% CI: 1.13–1.46) during the second trimester and the risk of LGA increased by 116% (HR: 2.16, 95%CI: 1.16–4.00) during the entire pregnancy, while the null or weaker association was observed at corresponding low (≤ 25th percentile) and medium (> 25th and ≤ 75th percentile) temperature levels. Conclusion: This multicity study added new evidence that ambient high temperature may enhance the potential effects of ambient O3 on adverse birth outcomes.

Although mounting evidence suggests that short-term exposure to ozone increases the risk of respiratory disease, cardiovascular disease and mortality, there are few studies comparing the effects of ozone in relation to urticaria in China. To evaluate the risks for urticaria exacerbations related to ambient ozone measured as 1-h maximum (O3-1 h max), maximum 8-h (O3-8 h max) and 24-h average (O3-24 h avg) concentrations. We calculated three metrics of ozone, 1-h maximum, maximum 8-h and 24-h average based on the hourly data. Generalized additive models with Poisson regression incorporating natural spline functions were used to investigate short-term effects on urticaria associated with ambient ozone pollution in Lanzhou, China, using 5 years of daily data (2013–2017). We also examined the association by sex, age and season. In all-year analyses, a 10 μg/m3 increase in daily average, O3-1 h max, O3-8 h max and O3-24 h avg at lag2 corresponded to an increase of 0.58%(95%CI: 0.26, 0.90), 0.82% (95%CI: 0.47, 1.16) and 2.17% (95%CI: 1.17, 2.79), respectively. The elderly populations and females were susceptible to O3, and the associations between ozone and urticaria appeared to be more evident during warm season than in the cold season. In conclusion, these results indicated that ozone, as a widespread pollutant, affects outpatient visits for urticaria in Lanzhou. [ABSTRACT FROM AUTHOR]

Climate change influences the current tropospheric ozone (O3) budget due to industrialization and urbanization processes. In recent years, the impact of elevated O3 on crop development and yield loss has emerged as one of the most important environmental issues, particularly in rural and suburban areas of the lower Indo-Gangetic Plains of India. The impact of the current tropospheric ozone (O3) on the crop yield, photosynthetic yield, and enzymatic antioxidants of six rice (Oryza sativa L.) cultivars (IR 36, MTU 1010, GB 3, Khitish, IET 4786, and Ganga Kaveri) was investigated with and without the application of ethylenediurea (EDU). The results revealed that O3 stress significantly affected crop yield, photosynthetic yield, and antioxidant enzymes. The findings showed that O3 toxicity induces oxidative stress biomarkers, i.e., malondialdehyde (MDA) content, and was manifested by increasing the enzymatic antioxidants, i.e., superoxidase dismutase (SOD) and catalase (CAT) in four rice cultivars (IR 36, GB 3, IET 4786, and Ganga Kaveri). At the same time, the results also illustrated that the rice cultivars MTU 1010 and Khitish are more tolerant to O3 stress as they had less oxidative damage, greater photosynthetic SPAD value, SOD and CAT activities, and lower MDA activity. The results also elucidated that the application of EDU decreased O3 toxicity in sensitive cultivars of rice by increasing antioxidant defense systems. The current O3 level is likely to show an additional increase in the near future, and the use of tolerant genotypes of rice may reduce the negative impacts of O3 on rice production. [ABSTRACT FROM AUTHOR]

Ambient ozone becomes one of significant environmental threats to chronic obstructive pulmonary disease (COPD) in recent decades. To date, however, few systematic analyses have been performed to quantify ozone-attributable disease burden, globally and regionally. In this study, we aimed to comprehensively depict the global trend of ozone-related COPD premature deaths and disability-adjusted life years (DALYs). We derived estimates of COPD burden attributable to ambient ozone for 204 countries and territories during 1990–2019 from the Global Burden of Disease Study 2019. We examined the number of deaths and DALYs, as well as age-standardized mortality rate (ASMR) and DALYs rate (ASDR) by sex, socio-demographic index (SDI), countries, and regions. Population attributable fractions (PAFs) were adopted to identify age groups vulnerable to ozone-related COPD. Estimated annual percentage changes (EAPCs) were calculated to assess the temporal trend of ozone-attributable COPD burden (e.g., ASMR and ASDR) between 1990 and 2019, using generalized linear models. Spearman rank correlation was applied to measure the relationships of estimated ASMR, ASDR, and EAPC with SDI. In 2019, COPD attributable to ambient ozone gave rise to 365.22 (95% uncertainty interval: 174.93 to 564.27) thousand deaths and 6.21 (2.99 to 9.63) million DALYs globally, representing a corresponding increase of 76.11% and 56.37% versus 1990. During 1990–2019, however, a yearly decline of 1.07% (0.81 to 1.33) was observed for ASMR and 1.30% (1.07 to 1.52) for ASDR. Considerable gender inequality continues in ozone-attributable COPD burden, with much greater impacts among men, and the gap is enlarged with the increase of age. In all age groups, the fractional contribution of ozone to COPD burden exhibited an overall increasing trend globally for both deaths (8.22% in 1990 versus 11.13% in 2019) and DALYs (6.70% in 1990 versus 8.34% in 2019). The burden of COPD caused by ambient ozone varied substantially by geographical and socioeconomic regions. In 2019, the greatest ASMR and ASDR were seen in South Asia, followed by East Asia and Central Sub-Saharan Africa. Despite the clear drop of age-standardized rates (EAPC<0) in high, high-middle, and middle SDI regions, ASMR and ASDR in low and low-middle SDI regions continuously raised between 1990 and 2019. Higher SDI was found to be associated with lower EAPCs in ASMR (rs=−0.4405, p<0.001) and ASDR (rs=−0.4510, p<0.001). Although the global ASMR and ASDR of COPD attributable to ambient ozone have decreased from 1990 to 2019, there has been an unnegligible increase in some low and low-middle SDI regions such as Southeast Asia, South Asia, and Andean Latin America. Findings may have some implications for formulating targeted plans and policies for future COPD prevention and ambient ozone management in different regions. [ABSTRACT FROM AUTHOR]

Rising tropospheric ozone (O3) is a serious threat to plants and animals in the present climate change scenario. High tropospheric O3 has the capability to disrupt cellular organelles leading to impaired photosynthesis and significant yield reduction. Apoplast and chloroplast are two important cellular components in a plant system. Their proteomic response with ethylenediurea (EDU) treatment under tropospheric O3 has not been explored till date. EDU (an organic compound) protects plants exclusively against harmful O3 effects through activation of antioxidant defense mechanism. The present study investigated the mode of action of EDU (hereafter MAE) by identifying proteins involved in apoplast and chloroplast pathways. Two wheat varieties viz. Kundan and PBW 343 (hereafter K and P respectively) and three EDU treatments (0= control, 200, and 300 ppm) have been used for the study. In apoplast isolates, proteins such as superoxide dismutase (SOD), amino methyltransferase, catalase, and Germin-like protein have shown active role by maintaining antioxidant defense system under EDU treatment. Differential expression of these proteins leads to enhanced antioxidative defense mechanisms inside and outside the cell. Chloroplast proteins such as Rubisco, Ferredoxin NADP- reductase (FNR), fructose,1-6 bis phosphatase (FBPase), ATP synthase, vacuolar proton ATPase, and chaperonin have regulated their abundance to minimize ozone stress under EDU treatment. After analyzing apoplast and chloroplast protein abundance, we have drawn a schematic representation of the MAE working mechanism. The present study showed that plants can be capable of O3 tolerance, which could be improved by optimizing the apoplast ROS pool under EDU treatment. [ABSTRACT FROM AUTHOR]

The aim of our study was to identify the factors substantially affecting day-to-day variability in O3 concentrations in Czech mountain forests and to describe their influence in detailed, quantitative way. We examined the effects of meteorology and ambient NOx recorded in regular long-term continuous monitoring at five mountain forest sites representing different regions, covering both polluted and relatively unpolluted areas over the time period of 1992–2018. To investigate the association between ambient O3 concentrations on one hand, and precursor NOx concentrations, and meteorology on the other hand, we used a generalized additive model, GAM, with semiparametric (penalized-spline-based) components to capture properly the possible departures from linearity that is not captured by traditional linear regression approaches. Our results revealed that the O3 concentrations showed significant associations with all selected explanatory variables, i.e., air temperature, global solar radiation (GLRD), relative humidity, and NOx. Apparently, both meteorology and air pollution are highly important for day-to-day O3 concentrations, and this finding is consistent for all five rural sites, representing middle-elevated forested mountain areas in Central Europe. In addition to individual variables, we were able to detect interactions between three pairs of explanatory variables, namely temperature*GLRD, temperature*relative humidity, and GLRD*relative humidity. Moreover, we confirmed non-linear O3 behavior toward all individual explanatory variables.

Abstract It is widely accepted that excessive loads of nitrogen (N) deposition and ambient ozone (O 3) endanger natural ecosystems and the environment. Despite substantial reductions in emissions since the early 1990s both in the Czech Republic and in neighbouring countries, neither O 3 exposures nor N deposition have yet decreased to acceptable levels relative to the recommended thresholds. Based on long-term monitoring and high-quality data, we have indicated the areas of special risk due to high N deposition and O 3 exposures in Czech forests in 2000–2015. The areas of potential risk denote those forests under the highest loads of N deposition and O 3 exposure on a regular basis. The underlying classification approach is relativistic, i.e. based ultimately on quartiles of pollution intensities and not derived from critical limits or loads. The forest areas under the highest O 3 exposures and N deposition are spatially disjunct. The highest O 3 exposures are in the southern and the highest N deposition is in the northern Czech Republic. In contrast to our assumption, only 1322 km2, i.e. 4.6% of the total forested area (28,782 km2) are overlapping areas with a potential risk due both to high O 3 exposures and to N deposition. Our results provide valuable input information for a more detailed environmental analysis, anticipated in the future, addressing to what extent the indicated areas at potential risk are associated with the actual negative impacts on forests. Graphical abstract Unlabelled Image Highlights • We mapped areas with high AOT40F and N deposition in Czech forests in 2000–2015. • Forest areas, under highest O 3 exposures and N deposition, are spatially disjunct. • The highest O 3 exposures are in southern, the highest N deposition in northern CR. [ABSTRACT FROM AUTHOR]

(1) Background: Hong Kong is one of the most densely populated cities in the world, with millions of people exposed to severe air pollution. Surface ozone, mostly produced photochemically from anthropogenic precursor gases, is harmful to both humans and vegetation. The phytotoxicity of ozone has been shown to damage plant photosynthesis, induce early leaf death, and retard growth. (2) Methods: We use genotypes of bush bean Phaseolus vulgaris with various degrees of sensitivity to ozone to investigate the impacts of ambient ozone on the morphology and development of the beans. We use ozone-induced foliar injury index and measure the flowering and fruit production to quantify the ozone stress on the plants. (3) Results: We expected that the ozone-sensitive genotype would suffer from a reduction of yield. Results, however, show that the ozone-sensitive genotype suffers higher ozone-induced foliar damage as expected but produces more pods and beans and heavier beans than the ozone-resistant genotype. (4) Conclusions: It is postulated that the high ozone sensitivity of the sensitive genotype causes stress-induced flowering, and therefore results in higher bean yield. A higher than ambient concentration of ozone is needed to negatively impact the yield production of the ozone-sensitive genotype. Meanwhile, ozone-induced foliar damage shows a graduated scale of damage pattern that can be useful for indicating ozone levels. This study demonstrates the usefulness of bioindicators to monitor the phytotoxic effects of ozone pollution in a subtropical city such as Hong Kong.

Remotely-sensed identification of ozone stress in crops can allow for selection of ozone resistant genotypes, improving yields. This is critical as population, food demand, and background tropospheric ozone are projected to increase over the next several decades. Visual scores of common ozone damage have been used to identify ozone-stress in bio-indicator plants. This paper evaluates the use of a visual scoring metric of ozone damage applied to soybeans. The scoring of the leaves is then combined with hyperspectral data to identify spectral indices specific to ozone damage. Two genotypes of soybean, Dwight and Pana, that have shown different sensitivities to ozone, were grown and visually scored for ozone-specific damage on multiple dates throughout the growing season. Leaf reflectance, foliar biophysical properties, and yield data were collected. Additionally, ozone bio-indicator plants, snap beans, and common milkweed, were investigated with visual scores and hyperspectral leaf data for comparison. The normalized difference spectral index (NDSI) was used to identify the significant bands in the visible (VIS), near infrared (NIR), and shortwave infrared (SWIR) that best correlated with visual damage score when used in the index. Results were then compared to multiple well-established indices. Indices were also evaluated for correlation with seed and pod weight. The ozone damage scoring metric for soybeans evaluated in August had a coefficient of determination of 0.60 with end-of-season pod weight and a Pearson correlation coefficient greater than 0.6 for photosynthetic rate, stomatal conductance, and transpiration. NDSI [R558, R563] correlated best with visual scores of ozone damage in soybeans when evaluating data from all observation dates. These wavelengths were similar to those identified as most sensitive to visual damage in August when used in NDSI (560 nm, 563 nm). NDSI [R560, R563] in August had the highest coefficient of determination for individual pod weight (R2 = 0.64) and seed weight (R2 = 0.54) when compared against 21 well-established indices used for identification of pigment or photosynthetic stress in plants. When evaluating use of spectral bands in NDSI, longer wavelengths in SWIR were identified as more sensitive to ozone visual damage. Trends in the bands and biophysical properties of the soybeans combined with evaluation of ozone data indicate likely timing of significant ozone damage as after late-July for this season. This work has implications for better spectral detection of ozone stress in crops and could help with efforts to identify ozone tolerant varieties to increase future yield.

Background Short-term exposure to ambient air pollution has been associated with lower pulmonary function and higher blood pressure (BP). However, controversy remains regarding the relationship between ambient multiple daily ozone (O 3 ) metrics and cardiopulmonary health outcomes, especially in the developing countries. Objectives To investigate and compare the short-term effects of various O 3 metrics on pulmonary function, fractional exhaled nitric oxide (FeNO) and BP in a panel study of COPD patients. Methods We measured pulmonary function, FeNO and BP repeatedly in a total of 43 patients with COPD for 215 home visits. Daily hourly ambient O 3 concentrations were obtained from central-monitoring stations close to subject residences. We calculated various O 3 metrics [daily 1-h maximum (O 3 -1 h max), maximum 8-h average (O 3 -8 h max) and 24-h average (O 3 -24 h avg)] based on the hourly data. Daily indoor O 3 concentrations were estimated based on estimated indoor/outdoor O 3 ratios. Linear mixed-effects models were used to estimate associations of various O 3 metrics with cardiopulmonary function variables. Results An interquartile range (IQR) increase in ambient O 3 -8 h max (80.5 μg/m 3 , 5-d) was associated with a 5.9% (95%CI: −11.0%, −0.7%) reduction in forced expiratory volume in 1 s (FEV 1 ) and a 6.2% (95%CI: −10.9%, −1.5%) reduction in peak expiratory flow (PEF). However, there were no significant negative associations between ambient O 3 -1 h max, O 3 -24 h avg and FEV 1 , PEF. An IQR increase in ambient O 3 -1 h max (85.3 μg/m 3 , 6-d) was associated with a 6.7 mmHg (95%CI: 0.7, 12.7) increase in systolic BP. The estimated indoor O 3 were still significantly associated with reduction of FEV 1 and PEF. No significant associations were found between various O 3 metrics and FeNO. Conclusions Our results provide clues for the adverse cardiopulmonary effects associated with various O 3 metrics in COPD patients and highlight that O 3 -8 h max was more closely associated with respiratory health variables. [ABSTRACT FROM AUTHOR]

Background Few multicity studies have addressed the health effects of ozone in China due to the scarcity of ozone monitoring data. A critical scientific and policy-relevant question is whether a threshold exists in the ozone-mortality relationship. Methods Using a generalized additive model and a univariate random-effects meta-analysis, this research evaluated the relationship between short-term ozone exposure and daily total mortality in seven cities of Jiangsu Province, China during 2013–2014. Spline, subset, and threshold models were applied to further evaluate whether a safe threshold level exists. Results This study found strong evidence that short-term ozone exposure is significantly associated with premature total mortality. A 10 μg/m 3 increase in the average of the current and previous days’ maximum 8-h average ozone concentration was associated with a 0.55% (95% posterior interval: 0.34%, 0.76%) increase of total mortality. This finding is robust when considering the confounding effect of PM 2.5 , PM 10 , NO 2 , and SO 2 . No consistent evidence was found for a threshold in the ozone-mortality concentration-response relationship down to concentrations well below the current Chinese Ambient Air Quality Standard (CAAQS) level 2 standard (160 μg/m 3 ). Conclusions Our findings suggest that ozone concentrations below the current CAAQS level 2 standard could still induce increased mortality risks in Jiangsu Province, China. Continuous air pollution control measures could yield important health benefits in Jiangsu Province, China, even in cities that meet the current CAAQS level 2 standard. [ABSTRACT FROM AUTHOR]

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The effects of increasing ambient ozone (O3) concentrations on food security has become a major concern as the demand for agricultural productivity is projected to increase significantly over the next several decades. In this contribution, the responses of common soybean genotypes (AK-HARROW, PI88788, DWIGHT, PANA, and WILLIAMS82) to ambient O3 are characterized using hyperspectral data and foliar biophysical, mineral nutrient concentrations and soybean yield. Specifically, leaf reflectance spectra measured at different growth stages and canopy layers were used to examine the spectral indices that were most strongly correlated with leaf physiological status. The effects of elevated O3 on six important nutrients (K, Ca, Mg, Fe, Mn and Cu) were evaluated by analyzing the variations in nutrient concentrations at two critical growth stages with increasing ambient O3 concentration using Partial Least Square Regression (PLSR). Lastly, the identified best spectral indices and the robust nutrient prediction models were extrapolated to the entire growth period to explore their ability to track the effects of ambient O3 concentrations on soybean physiology and nutrient uptake. The results showed that fluorescence yield (ΔF/Fm’) and photochemical quenching (qP) appear to be good indicators of soybean physiological responses to O3 stress that are echoed by the harvest index (HI). Newly identified normalized difference spectral index (NDSI) [R416, R2371] always had the highest correlation (R2 > 0.6) with ΔF/Fm’, qP and electron transport rate (ETR, μmol m−2 s−1) compared to the published indices. Additionally, there were significant and broad spectral regions in visible and near infrared region that were well-correlated with ΔF/Fm’ and selected NDSIs that were applicable to satellite observations. The results of nutrient modeling using PLSR explained 54–87% of the variance in nutrient concentrations, and the predicted mineral nutrient accumulation throughout the growing season reflected the responses of ozone tolerant and sensitive genotypes well. NDSI [R416, R2371] demonstrated great potential in regard to its sensitivity in tracking plant physiological responses to changing ambient O3 concentrations. The outcome of this research has potential implications for development of space-based observation of large-scale crop responses to O3 damage, as well as for biotechnological breeding efforts to improve ozone tolerance under future climate scenarios.

[Display omitted] • Ambient ozone exposure was associated with increased risk of adverse birth outcomes. • Ambient temperature could modify the ozone's effects on adverse birth outcomes. • Ambient high temperature may enhance the ozone's effects on adverse birth outcomes. Epidemiological studies suggest that both ambient ozone (O 3) and temperature were associated with increased risks of adverse birth outcomes. However, very few studies explored their interaction effects, especially for small for gestational age (SGA) and large for gestational age (LGA). To estimate the modification effects of ambient temperature on associations of ambient O 3 exposure before and during pregnancy with preterm birth (PTB), low birth weight (LBW), SGA and LGA based on multicity birth cohorts. A total of 56,905 singleton pregnant women from three birth cohorts conducted in Tianjin, Beijing and Maoming, China, were included in the study. Maximum daily 8-h average O 3 concentrations of each pregnant woman from the preconception period to delivery for every day were estimated by matching their home addresses with the Tracking Air Pollution in China (TAP) datasets. We first applied the Cox proportional-hazards regression model to evaluate the city-specific effects of O 3 exposure before and during pregnancy on adverse birth outcomes at different temperature levels with adjustment for potential confounders, and then a meta-analysis across three birth cohorts was conducted to calculate the pooled associations. In pooled analysis, significant modification effects of ambient temperature on associations of ambient O 3 with PTB, LBW and LGA were observed (P interaction < 0.05). For a 10 μg/m3 increase in ambient O 3 exposure at high temperature level (> 75th percentile), the risk of LBW increased by 28 % (HR: 1.28, 95% CI: 1.13–1.46) during the second trimester and the risk of LGA increased by 116% (HR: 2.16, 95%CI: 1.16–4.00) during the entire pregnancy, while the null or weaker association was observed at corresponding low (≤ 25th percentile) and medium (> 25th and ≤ 75th percentile) temperature levels. This multicity study added new evidence that ambient high temperature may enhance the potential effects of ambient O 3 on adverse birth outcomes. [ABSTRACT FROM AUTHOR]

A field study was conducted to evaluate the effects of ambient ozone (O 3 ) on an O 3 -sensitive poplar ( Populus cathayana) by using ethylenediurea (EDU) as a chemical protectant under two soil water treatments (well-watered (WW) and moderate drought (MD, 50–60% of WW in volumetric soil water content). EDU was applied as foliar spray at 0, 300, 450, and 600 ppm. Photosynthetic parameters, pigment contents, leaf nitrogen, antioxidant capacity, growth, and biomass were measured. The 8 h (9:00–17:00) average ambient O 3 concentration was 71.7 ppb, and AOT40 was 29.2 ppm h during the experimental period (9 June to 21 September), which was high enough to cause plant injury. MD had significantly negative effects on P. cathayana, as indicated by reduced photosynthesis, growth, and biomass, and higher MDA contents. On the other hand, EDU significantly increased photosynthesis rate, chlorophyll a fluorescence, V cmax and J max , photosynthetic pigments, total antioxidant capacity, tree growth and biomass accumulation, and reduced lipid peroxidation, but there was no significant interaction between EDU and drought for most parameters, indicating that EDU can efficiently protect Populus cathayana against ambient O 3 and the protection was not affected by soil water contents when soil water reached moderate drought level. Among all doses, EDU at 450 ppm provided maximum protection. Comparison of EDU-treated and non-treated P. cathayana could be used as a biomarker system in risk assessment of the effects of ambient O 3 on forest health. [ABSTRACT FROM AUTHOR]

We present results of the 5-year monitoring of ambient O concentrations in a Central European medium altitude mountain forested area. O levels were measured at 11 sites between 714 and 1000 m a.s.l. in 2006-2010 vegetation seasons using Ogawa diffusive samplers. Our results reveal that O exposure in the Jizerské hory Mts. was relatively high and comparable with polluted sites in Southern Europe and in higher altitudes. O concentrations differed significantly between individual sites and in individual years. O concentrations showed clear dependence on altitude at sites with similar aspect. Its gradient for the entire 5-year period under review equaled 3.5 ppb/100 m of altitude, ranging between nearly 5 ppb/100 m of altitude in 2006 and nearly 3 ppb/100 m of altitude in 2010. O concentrations at the site with northern aspect were consistently significantly lower than at the site at similar altitude with southern aspect. O concentrations measured at the forest edge were consistently lower than those measured at the same site but at the forest clearing. It is evident that the macro-setting of the O monitoring site is crucial for obtaining reliable results with high representativeness for the area. [ABSTRACT FROM AUTHOR]