水中有机磷农药二嗪农的臭氧化降解机制及影响因素

目的臭氧是一种清洁高效的饮用水消毒剂，并能氧化水中有机污染物而不产生消毒副产物，广泛地用于饮用水处理。方法臭氧与有机磷农药二嗪农反应后，采用GC-MS对中间产物进行定性分析，用HPLC监测二嗪农的残留量和中间产物的生成量，研究二嗪农的臭氧降解动力、机制及影响因素。结果二嗪农的臭氧降解由臭氧直接氧化和羟基自由基间接氧化共同作用，并遵循假一级动力学。降解受离子清除剂与溶液pH的影响。加入50mmol／L的离子清除剂和降低溶液pH都使二嗪农的臭氧降解速率常数明显减小。结论通过GC-MS分析，确定了二嗪氧磷为二嗪农的臭氧化中间产物，提高溶液pH有利于二嗪氧磷进一步降解，而加入离子清除剂则不利于二嗪氧磷的降解。     

Laboratory study of heterogeneous ice nucleation in deposition mode of montmorillonite mineral dust particles aged with ammonia, sulfur dioxide, and ozone at polluted atmospheric concentrations

Heterogeneous ice nucleation in deposition mode of montmorillonite mineral dust aerosol particles exposed to atmospheric trace gases (ammonia, sulfur dioxide, and ozone) was studied at temperatures warmer than −40°C with a continuous flow diffusion chamber. Pure and typical polluted atmospheric concentrations of ammonia, sulfur dioxide, and ozone gases were used to age montmorillonite mineral dust aerosol particles at room temperature and atmospheric pressure in a stainless steel chamber. Ammonia-, sulfur dioxide-, and ozone-exposed montmorillonite mineral dust aerosols act as ice nuclei in heterogeneous deposition freezing at warmer temperatures than required for homogeneous freezing. The ice nucleation efficiency of montmorillonite mineral dust aerosols increased about two times due to exposure to ammonia at a typical atmospheric concentration of about 100 ppt. This is the first experimental evidence for the enhancement of the ice nucleation efficiency of montmorillonite mineral dust aerosols by ammonia gas at typical atmospheric concentrations. Montmorillonite exposure to either pure (100%) or 45 ppm sulfur dioxide or to ozone at 200 ppb shows no clear evidence for changing the ice nucleation efficiency of montmorillonite mineral dust particles. Thus, we conclude that enhancements atmospheric trace gases (e.g., sulfur dioxide and ozone) due to anthropogenic activities have no significant impact on the heterogeneous ice nucleation of montmorillonite mineral dust particles.     

催化-臭氧在游泳池水质处理的应用

目的:建立一种用催化-臭氧方法氧化游泳池水中尿素,以使得游泳池水中的尿素、细菌总数、大肠菌群指标符合国家标准。方法:用不同的方法,如改性沸石过滤试验;加氯试验;臭氧氧化试验;臭氧加入催化剂(催化剂为硫酸铜或五氧化二矾)等试验观察尿素的去除效果。结果:催化-臭氧方法去除尿素效果最好,臭氧加入以硫酸铜为催化剂的催化方法尿素去除率为76.3%,臭氧加入以五氧化二矾为催化剂的催化方法尿素去除率为76.8%,高浓度氯(有效氯含量5.0 mg/L)消毒剂效果次之,去除率为46.1%。结论:理想的去除游泳池水尿素及杀灭细菌的有效方法为臭氧发生器连接游泳池本身的循环水处理系统。     

Ozone air pollution and daily mortality in Genoa, Italy between 1993 and 1996

The association between ozone (O3) and daily mortality was investigated in Genoa, an Italian city characterized by a Mediterranean climate and a high prevalence of elderly inhabitants. The O3 effect, adjusted for long time trend, seasonality and weather, was assessed using Poisson regression modelling, allowing for overdispersion and autocorrelation, and expressed as mean variation percent of daily mortality per 50 microg/m3 increase (MV). Significant MVs for overall (+4.0%) and cardiovascular (+7.2%) mortality were detected at 1-day lag. The effects were stronger in the warmer season (May-October). Similar estimates were found after restricting the analyses to the elderly (>or=75 years). Furthermore, in this group, higher MVs were observed for total mortality at 2-day lag. A statistically significant synergistic effect between O3 and temperature was observed for cardiovascular mortality, particularly in elderly people, with an evident increase in mortality risk above 26 degrees C (MV +30.0% for the whole population and +40.0% for the elderly, respectively). This investigation highlights the importance of taking local climatic and demographic features into account when comparing different time-series studies, and substantiates the influence of photochemical pollution on mortality trends in small urban areas.     

Potential Oxidative Stress in the Bodies of Electric Arc Welding Operators： Effect of Photochemical Smog

INTRODUCTION Electric arc welding is widely used in many fields such as welding engineering, architectural engineering, automotive industry, boat and ship engineering, aerospace C…     

Acute effects of urban ambient air pollution on respiratory symptoms, asthma medication use, and doctor visits for asthma in a cohort of Australian children

We enrolled a cohort of primary school children with a history of wheeze (n=148) in an 11-month longitudinal study to examine the relationship between ambient air pollution and respiratory morbidity. We obtained daily air pollution (ozone, particulate matter less than 10 microm, and nitrogen dioxide), meteorological, and pollen data. One hundred twenty-five children remained in the final analysis. We used logistic regression models to determine associations between air pollution and respiratory symptoms, asthma medication use, and doctor visits for asthma. There were no associations between ambient ozone concentrations and respiratory symptoms, asthma medication use, and doctor visits for asthma. There was, however, an association between PM(10) concentrations and doctor visits for asthma (RR=1.11, 95% CI=1.04-1.19) and between NO(2) concentration and wet cough (RR=1.05, 95% CI=1.003-1.10) in single-pollutant models. The associations remained significant in multipollutant models. There was no consistent evidence that children with wheeze, positive histamine challenge, and doctor diagnosis of asthma reacted differently to air pollution from children with wheeze and doctor diagnosis of asthma and children with wheeze only. There were significant associations between PM(10) levels and doctor visits for asthma and an association between NO(2) levels and the prevalence of wet cough. We were, however, unable to demonstrate that current levels of ambient air pollution in western Sydney have a coherent range of adverse health effects on children with a history of wheezing.     

Postnatal remodeling of the neural components of the epithelial-mesenchymal trophic unit in the proximal airways of infant rhesus monkeys exposed to ozone and allergen

Nerves and neuroendocrine cells located within the airway epithelium are ideally situated to sample a changing airway environment, to transmit that information to the central nervous system, and to promote trophic interactions between epithelial and mesenchymal cellular and acellular components. We tested the hypothesis that the environmental stresses of ozone (O(3)) and house dust mite allergen (HDMA) in atopic infant rhesus monkeys alter the distribution of airway nerves. Midlevel bronchi and bronchioles from 6-month-old infant monkeys that inhaled filtered air (FA), house dust mite allergen HDMA, O(3), or HDMA + O(3) for 11 episodes (5 days each, 0.5 ppm O(3), 8 h/day followed by 9 days recovery) were examined using immunohistochemistry for the presence of Protein gene product 9.5 (PGP 9.5), a nonspecific neural indicator, and calcitonin gene-related peptide (CGRP). Along the axial path between the sixth and the seventh intrapulmonary airway generations, there were small significant (P < 0.05) decrements in the density of epithelial nerves in monkeys exposed to HDMA or O(3), while in monkeys exposed to HDMA + O(3) there was a greater significant (P < 0.05) reduction in epithelial innervation. In animals exposed to O(3) or HDMA + O(3) there was a significant increase in the number of PGP 9.5 positive/CGRP negative cells that were anchored to the basal lamina and emitted projections in primarily the lateral plain and often intertwined with projections and cell bodies of other similar cells. We conclude that repeated cycles of acute injury and repair associated with the episodic pattern of ozone and allergen exposure alter the normal development of neural innervation of the epithelial compartment and the appearance of a new population of undefined PGP 9.5 positive cells within the epithelium.     

Effects of ozone on DNA single-strand breaks and 8-oxoguanine formation in A549 cells

Animal studies have demonstrated that ozone exposure can induce lung tumors. Recent epidemiological studies have also shown that increased ozone exposure is associated with a greater risk of lung cancer. This study used single-cell gel electrophoresis (the Comet assay) and flow cytometry to investigate DNA damage in A549 cells exposed to ozone levels below the current ambient standard. Cells were exposed to ozone at levels of 0, 60, 80, and 120 ppb, and then DNA single-strand breaks and 8-oxoguanine levels were measured. Additionally, the formamidopyrimidine glycosylase (Fpg) repair enzyme was added to the Comet assay to enhance detection of oxidative damage. Vitamins C and E were also added to determine their inhibitory effects on ozone-induced 8-oxoguanine. Measurements of tail length, tail intensity, and tail moment of the Comet assay were shown to correlate with each other. However, tail moment appeared to be more sensitive than the other two indicators in detecting DNA single-strand breaks. Tail moments of cells exposed to 80 and 120 ppb of ozone were significantly higher than those exposed to 0 ppb (P<0.05). These three indicators of DNA single-strand breaks with Fpg were shown to be increased and more sensitive than those without Fpg. After Fpg was introduced, the tail moments at ozone levels of 60, 80, and 120 ppb were significantly higher than those at 0 ppb (P<0.05). Furthermore, 8-oxoguanine levels, determined by fluorescence intensity, at 80 and 120 ppb of ozone exposure were significantly higher than the level at 0 ppb. Pretreatment with vitamins C and E reduced the 8-oxoguanine levels caused by ozone. We conclude that ozone levels below current ambient standards may induce DNA breaks and oxidative DNA damage. Moreover, the Fpg repair enzyme in the Comet assay can increase the sensitivity of oxidative damage detection in vitro.     

臭氧与胶原酶治疗腰椎间盘突出症的临床比较

目的比较和评价臭氧消融术与胶原酶化学溶解术治疗腰椎间盘突出症的疗效。方法142例腰椎间盘突出症患者,根据治疗方法不同分为2组,Ⅰ组70例,Ⅱ组72例。Ⅰ组采用臭氧消融术治疗,Ⅱ组采用胶原酶溶解术治疗。随访1周、3个月、6个月比较两组治疗效果。结果治疗后1周Ⅰ组、Ⅱ组的优良率分别为85.7%(60/70例)、68.1%(49/72例),术后随访,于3个月、6个月时的优良率Ⅰ组分别为88.6%(62/70例)、90.0%(63/70例),Ⅱ组为88.9%(64/72例)、91.7%(66/72例),两组疗效于治疗后1周时优良率的差异有统计学意义(P<0.05),3个月和6个月后优良率对比的差异无统计学意义(P>0.05)。结论臭氧消融术和胶原酶溶解术均为治疗腰椎间盘突出症的有效疗法。臭氧消融术的近期疗效明显优于胶原酶溶解术,但远期疗效两组差异无统计学意义。     

椎间盘突出症不同治疗方法回顾性分析

目的分析臭氧髓核消溶术（A组）、后路开窗髓核摘除术（B组）以及胶原酶化学髓核消溶术（C组）治疗椎间盘突出症的方法和后期效果。方法采用统一的病例选择和疗效标准,对185例患者（其中A组60例,B组63例,C组62例）进行分析,比较3组治疗后评分和优良率。结果A组治疗后评分和优良率明显高于B组和C组,有非常显著性差异（P〈0.01）,B组高于C组有显著性差异（P〈0.05）。结论椎间盘突出症不同治疗方法中,臭氧髓核消溶术和胶原酶化学髓核消溶术明显优于开窗髓核摘除术,具有基本无创的优点。而开窗髓核摘除术相对而言创伤较大,对脊柱的稳定性有一定的影响。臭氧髓核消溶术是椎间盘突出症治疗方法中最理想的方法。