Implications of 1.5 K climate warming on warm-season ozone exposure and atmospheric oxidation capacity in China

Surface ozone(O_(3))poses significant threats to public health,agricultural crops,and plants in natural ecosystems.Global warming is likely to increase future O_(3)mainly by altering atmospheric photochemical reactions and enhancing biogenic volatile organic compound(BVOC)emissions.To assess the impacts of the future 1.5 K climate target on O_(3)concentrations and ecological O_(3)exposure in China,numerical simulations were conducted using the CMAQ(Community Multiscale Air Quality)model during April-October 2018.Ecological O_(3)exposure was estimated using six indices(i.e.,M7,M24,N100,SUM60,W126,and AOT40f).The results show that the temperature rise increases the MDA8 O_(3)(maximum daily eight-hour average O_(3))concentrations by∼3 ppb and the number of O_(3)exceedance days by 10-20 days in the North China Plain(NCP),Yangtze River Delta(YRD),and Sichuan Basin(SCB)regions.All O_(3)exposure indices show substantial increases.M24 and M7 in eastern and southern China will rise by 1-3 ppb and 2-4 ppb,respectively.N100 increases by more than 120 h in the surrounding regions of Beijing.SUM60 increases by greater than 9 ppm h^(−1),W126 increases by greater than 15 ppm h^(−1)in Shaanxi and SCB,and AOT40f increases by 6 ppm h^(−1)in NCP and SCB.The temperature increase also promotes atmospheric oxidation capacity(AOC)levels,with the higher AOC contributed by OH radicals in southern China but by NO_(3)radicals in northern China.The change in the reaction rate caused by the temperature increase has a greater influence on O_(3)exposure and AOC than the change in BVOC emissions.

Protecting the photosynthetic performance of snap bean under free air ozone exposure

Tropospheric ozone（O3） is a major air pollutant and causes serious injury to vegetation. To protect sensitive plants from O3 damage, several agrochemicals have been assessed,including cytokinin（e.g., kinetin, KIN） and ethylenediurea（EDU） with cytokinin-like activity.In higher plant, leaves are primarily injured by O3 and protective agrochemicals are often applied by leaf spraying. To our knowledge, the mitigating abilities of EDU and KIN have not been compared directly in a realistic setup. In the present research, impacts of elevated O3（2 × ambient O3, 24 hr per day, for 8 days） on an O3 sensitive line（S156） of snap bean（Phaseolus vulgaris）, which is often used for biomonitoring O3 pollution, were studied in a free air controlled exposure system. The day before starting the O3 exposure, plants were sprayed with a solution of EDU（300 ppm）, KIN（1 mmol/L） or distilled water, to compare their protective abilities. The results demonstrated that 2 × ambient O3 inhibited net photosynthetic rate and stomatal conductance, increased the minimal fluorescence yield of the dark-adapted state, decreased the maximal quantum yield of PSII photochemistry, and led to visible injury. KIN and EDU alleviated the reduction of the photosynthetic performance, and visible injury under O3 fumigation. The plants sprayed with EDU showed greater ability to mitigate the O3 damage than those sprayed with KIN. Chlorophyll fluorescence imaging may have detected more precisely the differences in O3 response across the leaf than the conventional fluorometer.

Ambient Ozone Exposure, Semen Plasma Metabolites, and Sperm Quality Decline among Adult Men in Wuhan China

Ambient ozone(O3)exposure may be associated with a reduction of semen quality,yet the potential biological mechanisms remain unclear.We investigated the effects of certain seminal plasma metabolites on mediating the links between O3 exposure and the deterioration of semen quality.The untargeted metabolomics analysis was performed on semen samples of 200 Chinese adult men to determine candidate metabolites associated with characteristics of semen quality.Mediation analysis was adopted to examine whether these metabolites modulated the links between O3 exposure and semen quality.We found a significant reduction in sperm concentration by−28.1%(95%CI:−41.7%,−11.3%),and sperm count by−29.2%(95%CI:−43.7%,−11.0%)associated with each 10μg/m3 increase in ambient O3 concentration during the period of sperm development.We delineated 7 metabolites in seminal fluid that substantially mediated the links between O3 exposure and declined semen quality,including myristoleic acid,aspartyl-isoleucine,phenylethyl primeveroside,ACar(18:2),ACar(18:1),FAHFA(22:6/22:3),and LPS(22:5).Among these,myristoleic acid exhibited the most pronounced mediation effects,with its indirect effect of which accounts for 46.4%of the overall association.Our findings suggested that exposure to ozone decreased sperm quality by disrupting fatty acid metabolism,particularly myristoleic acid.

Effect of tibolone pretreatment on kinases and phosphatases that regulate the expression and phosphorylation of Tau in the hippocampus of rats exposed to ozone

Oxidative stress （OS） is a key process in the development of many neurodegenerative diseases, memory disorders, and other pathological processes related to aging. Tibolone （TIB）, a synthetic hormone used as a treatment for menopausal ymptoms, decreases lipoperoxidation levels, prevents memory impairment and learning disability caused by ozone （O3） exposure. However, it is not clear if TIB could prevent the increase in phosphorylation induced by oxidative stress of the microtubule-associated protein Tau. In this study, the effects of TIB at different times of administration on the phosphorylation of Tau, the activation of glycogen synthase kinase-3β （GSK3β）, and the inactivation of Akt and phosphatases PP2A and PTEN induced by O3 exposure were assessed in adult male Wistar rats. Rats were divided into 10 groups： control group （ozone-free air plus vehicle [C]）, control ＋ TIB group （ozone-free air plus TIB 1 mg/kg [C ＋ TIB]）; 7,15, 30, and 60 days of ozone exposure groups [O3] and 7, 15, 30, and 60 days of TIB 1 mg/kg before ozone exposure groups [O3 ＋ TIB]. The effects of O3 exposure and TIB administration were assessed by western blot analysis of total and phosphorylated Tau, GSK3β, Akt, PP2A, and PTEN proteins and oxidative stress marker nitrotyrosine, and superoxide dismutase activity and lipid peroxidation of malondialdehyde by two different spectrophotometric methods （Marklund and TBARS, respectively）. We observed that O3 exposure increases Tau phosphorylation, which is correlated with decreased PP2A and PTEN protein levels, diminished Akt protein levels, and increased GSK3β protein levels in the hippocampus of adult male rats. The effects of O3 exposure were prevented by the long-term treatment （over 15 days） with TIB. Malondialdehyde and nitrotyrosine levels increased from 15 to 60 days of exposure to O3 in comparison to C group, and superoxide dismutase activity decreased. Furthermore, TIB administration limited the changes induced by O3 exposure. Our results suggest a beneficial use of hormone replacement therapy with TIB to prevent neurodegeneration caused by O3 exposure in rats.

Interaction between ozone and paternal smoking on fetal congenital heart defects among pregnant women at high risk a multicenter maternal-fetal medicine study

Background Evidence remains limited on the association between maternal ozone(O,)exposure and congenital heart defects(CHDs)in offspring,and few studies have investigated the interaction and modification of paternal smoking on this association.Methods Using a sample including pregnant women at high risk of fetal CHD(with metabolic disease,first-trimester viral infection,family history of CHD,etc.)from a maternal-fetal medicine study covering 1313 referral hospitals in China during 2013-2021,we examined the associations between maternal O_(3)exposure during 3-8 weeks of gestational age and fetal CHD in offspring and investigated the interaction and modification of paternal smoking on this association.CHD was diagnosed by fetal echocardiograms,maximum daily 8-hour average O,exposure data at a 10 km×10 km spatial resolution came from the Tracking Air Pollution in China dataset,and paternal smoking was collected using questionnaires.Logistic regression models were used to estimate adjusted odds ratios(ORs)and 95%confidence intervals(CIs).Results Among 27,834 pregnant women at high risk of fetal CHD,17.4%of fetuses were diagnosed with CHD.Each 10μg/m^(3)increase in maternal O_(3)exposure was associated with a 17%increased risk of CHD in offspring(OR=1.17,95%CI=1.14-1.20).Compared with paternal nonsmoking and maternal low O_(3)exposure,the ORs(95%CI)of CHD for smoking and low O_(3)exposure,nonsmoking and high O_(3)exposure,and smoking and high O_(3)exposure were 1.25(1.08-1.45),1.81(1.56-2.08),and 2.23(1.84-2.71),respectively.Paternal smoking cessation seemingly mitigated the increased risk of CHD.Conclusions Maternal O_(3)exposure and paternal smoking were interactively associated with an increased risk of fetal CHD in offspring,which calls for effective measures to decrease maternal exposure to O_(3)pollution and secondhand smoke for CHDprevention.