Characterization and sources of volatile organic compounds (VOCs) during ozone pollution events in Chengdu plain, Southwest China

2020 ◽  
Author(s):  
Mengdi Song ◽  
Xin Li ◽  
Suding Yang ◽  
Xuena Yu ◽  
Shiyi Chen ◽  
...  
Keyword(s):  
Large Fraction ◽  
Ozone Pollution ◽  
Annual Average ◽  
Mean Values ◽  
Ozone Precursors ◽  
Chengdu Plain ◽  
Potential Source ◽  
Pollution Event ◽  
The Difference ◽  
Pollution Events

<p>Since 2015, the annual average ozone (O<sub>3</sub>) concentration in Chengdu has shown significant positive trends and reached a maximum of 55.2 ppb in 2018. By 2019, the annual average O<sub>3</sub> value has slightly decreased to 52.9 ppb, but it is still at the highest level in the Sichuan Basin. In order to illuminate VOCs characteristics, identify critical ozone precursors and explore potential sources during ozone pollution events in Chengdu plain, we performed a comprehensive field observation campaign from 9 August to 14 September 2019. During the campaign, the averaged O<sub>3</sub> concentration was 29.1 ppb, and mean values of ozone precursors NOx and TVOC were 14.9 ppb and 31.3 ppb, respectively. Two severe ozone pollution events occurred in Chengdu during the observation period. In ozone pollution event 1, the ratios of the average O<sub>3</sub>, NOx, NMHCs, and OVOCs concentration on the polluted days relative to the clean days were 4.1, 0.3, 0.6, and 1.4, respectively. In ozone pollution event 2, the ratios of the average O<sub>3</sub>, NOx, NMHCs, and OVOCs concentration on the polluted days relative to the clean days were 3.4, 0.4, 0.6 and 2.1, respectively. The difference of the ratios indicates that there are secondary conversions of NMHCs and NOx and secondary formation of O<sub>3</sub> and OVOCs during the pollution period. Isoprene, Acetaldehyde, Methyl Vinyl Ketone, m/p-Xylene and 1-Butene constitute a large fraction of the L<sub>OH</sub> during polluted days.  In this study, air mass cluster analysis, the potential source contribution function (PSCF), and positive matrix factorization (PMF) receptor models were used in combination to analyze the sources and potential source areas of VOCs during O3 pollution events.</p>

scholarly journals The effect of using limited scene-dependent averaging kernels approximations for the implementation of fast Observing System Simulation Experiments targeted on lower tropospheric ozone

2013 ◽  
Vol 6 (2) ◽  
pp. 2413-2448 ◽  
Author(s):  
P. Sellitto ◽  
G. Dufour ◽  
M. Eremenko ◽  
J. Cuesta ◽  
V.-H. Peuch ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Tropospheric Ozone ◽  
System Simulation ◽  
Ozone Pollution ◽  
Simulation Experiments ◽  
Atmospheric Species ◽  
Radiative Transfer Calculation ◽  
Pollution Event ◽  
Pollution Events ◽  
Simulation Exercises

Abstract. Practical implementations of chemical OSSEs (Observing System Simulation Experiments) usually rely on approximations of the pseudo-observations by means of a prior parametrization of the averaging kernels, which describe the sensitivity of the observing systems to the target atmospheric species. This is intended to avoid the need for use of a computationally expensive pseudo-observations simulator that relies on full radiative transfer calculations. Here we present an investigation on how no, or limited, scene dependent averaging kernels parametrizations may misrepresent the sensitivity of an observing system, and thus possibly lead to inaccurate results of OSSEs. We carried out the full radiative transfer calculation for a three-days period over Europe, to produce reference pseudo-observations of lower tropospheric ozone, as they would be observed by a concept geostationary observing system called MAGEAQ (Monitoring the Atmosphere from Geostationary orbit for European Air Quality). The selected spatiotemporal interval is characterized by a peculiar ozone pollution event. We then compared our reference with approximated pseudo-observations, following existing simulation exercises made for both the MAGEAQ and GEOstationary Coastal and Air Pollution Events (GEO-CAPE) missions. We found that approximated averaging kernels may fail to replicate the variability of the full radiative transfer calculations. Then, we compared the full radiative transfer and the approximated pseudo-observations during a pollution event. We found that the approximations substantially overestimate the capability of the MAGEAQ to follow the spatiotemporal variations of the lower tropospheric ozone in selected areas. We conclude that such approximations may lead to false conclusions if used in an OSSE. Thus, we recommend to use comprehensive scene-dependent approximations of the averaging kernels, in cases where the full radiative transfer is computationally too costly for the OSSE being investigated.

scholarly journals Characteristics of Ground-Level Ozone from 2015 to 2018 in BTH Area, China

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 130 ◽  
Author(s):  
Xiaozhen Fang ◽  
Huayun Xiao ◽  
Haixu Sun ◽  
Cheng Liu ◽  
Zhongyi Zhang ◽  
...  
Keyword(s):  
Air Pollutants ◽  
Surface Ozone ◽  
Ground Level ◽  
Weekend Effect ◽  
Photochemical Oxidation ◽  
Ozone Pollution ◽  
Ground Level Ozone ◽  
Ozone Precursors ◽  
Pollution Problem ◽  
The Difference

With the ground-level ozone pollution problem increasingly prominent in recent years in China, it is particularly important in basic researches on ozone contamination characteristics. In this study, 13 cities in Beijing-Tianjin-Hebei (BTH) area were examined to determine the characteristics of surface ozone (O3) from 2015 to 2018. Due to the photochemical oxidation of ozone precursors (such as nitrogen oxides and carbon monoxide) along with the presence of sunlight and characteristics of local emission sources, the O3 and oxidant (OX) concentrations showed obvious seasonal variation and daily variation. It implicated that the O3 concentrations reached the maximum during summer. The concentrations of O3 were higher at daytime than those measured at nighttime. The ozone weekend effect was estimated by the difference and deviation, which exhibited that the difference between weekday and weekend were related to the concentrations of ozone precursors and PM, vehicle emissions, and solar radiation. Moreover, the O3 concentrations decreased with the increase of other air pollutants by correlation analysis. The ozone pollution was easily formed at light and moderate polluted periods when compared to other air quality levels.

Seasonal trends in the stable isotopic composition of snow and meltwater runoff in a subarctic catchment at Okstindan, Norway

2004 ◽  
Vol 35 (2) ◽  
pp. 119-137 ◽  
Author(s):  
S.D. Gurney ◽  
D.S.L. Lawrence
Keyword(s):  
Isotopic Composition ◽  
Mean Value ◽  
Mean Values ◽  
Stable Isotopic Composition ◽  
Meltwater Runoff ◽  
Stable Isotopic ◽  
The Mean ◽  
The Difference ◽  
Δ18o And Δd

Seasonal variations in the stable isotopic composition of snow and meltwater were investigated in a sub-arctic, mountainous, but non-glacial, catchment at Okstindan in northern Norway based on analyses of δ18O and δD. Samples were collected during four field periods (August 1998; April 1999; June 1999 and August 1999) at three sites lying on an altitudinal transect (740–970 m a.s.l.). Snowpack data display an increase in the mean values of δ18O (increasing from a mean value of −13.51 to −11.49‰ between April and August), as well as a decrease in variability through the melt period. Comparison with a regional meteoric water line indicates that the slope of the δ18O–δD line for the snowpacks decreases over the same period, dropping from 7.49 to approximately 6.2.This change points to the role of evaporation in snowpack ablation and is confirmed by the vertical profile of deuterium excess. Snowpack seepage data, although limited, also suggest reduced values of δD, as might be associated with local evaporation during meltwater generation. In general, meltwaters were depleted in δ18O relative to the source snowpack at the peak of the melt (June), but later in the year (August) the difference between the two was not statistically significant. The diurnal pattern of isotopic composition indicates that the most depleted meltwaters coincide with the peak in temperature and, hence, meltwater production.

DIE AUSSCHEIDUNG VON TESTOSTERON UND EPITESTOSTERON BEI FRAUEN AM ENDE DER SCHWANGERSCHAFT

1969 ◽  
Vol 60 (4) ◽  
pp. 579-585
Author(s):  
K. Schollberg ◽  
E. Seiler ◽  
J. Holtorff
Keyword(s):  
Urinary Excretion ◽  
Late Pregnancy ◽  
Mean Values ◽  
Pregnant Females ◽  
Female Foetus ◽  
The Mean ◽  
The Difference ◽  
Normal Women ◽  
In Pregnancy

ABSTRACT The urinary excretion of testosterone and epitestosterone by women in late pregnancy has been studied. The mean values of 22 normal women in pregnancy mens X are 12.9 ± 9.2 μg/24 h in the case of testosterone and 16.1 ± 16.2 μg/24 h in the case of epitestosterone. Both values do not differ significantly from those of non-pregnant females. The excretion values of mothers bearing a male foetus (17.3 ± 8.9 μg/24 h) are higher than those of mothers with a female foetus (6.4 ± 4.8 μg/24 h). The difference is statistically significant with P = 0.01.

scholarly journals Influence of Apical Patency and Cleaning of the Apical Foramen on Periapical Extrusion in Retreatment

2013 ◽  
Vol 24 (5) ◽  
pp. 482-486 ◽  
Author(s):  
Marili Doro Andrade Deonizio ◽  
Gilson Blitzkow Sydney ◽  
Antonio Batista ◽  
Roberto Pontarolo ◽  
Paulo Ricardo Bittencourt Guimarães ◽  
...  
Keyword(s):  
Material Removal ◽  
Filling Material ◽  
Mean Values ◽  
Filtration System ◽  
Root Canal Retreatment ◽  
Significant Difference ◽  
Before And After ◽  
The Mean ◽  
The Difference ◽  
Removal Technique

This study evaluated the influence of apical patency, root filling removal technique and cleaning of the apical foramen, concerning the amount of debris extruded during root canal retreatment. Forty mandibular incisors were randomly assigned to 4 groups - GIM (n=10), GIIM (n=10), GIPT (n=10) and GIIPT (n=10), which were named according to leaving (I) or not (II) apical patency during canal preparation and filling removal technique (manual - M or ProTaper system - PT). After filling material removal, each specimen of each group had the apical foramen cleaned by sizes 15, 20 and 25 instruments, generating 12 subgroups: GIM15, GIM20, GIM25, GIIM15, GIIM20, GIIM25, GIPT15, GIPT20, GIPT25, GIIPT15, GIIPT20 and GIIPT25. Extruded filling debris was collected by a Milipore filtration system, an HV-durapore, 0.45 µm pore filter with a 25 mm diameter. The filters were weighed before and after the collection on an analytical scale (10–5 g), and the difference was calculated. The mean weight of extruded filling debris was analyzed statistically by Kruskal-Wallis and Friedman ANOVA tests (α=0.05). The mean values found in the groups (in mg) were: GIM (0.95±0.94), GIIM (0.47±0.62), GIPT (0.30±0.31) and GIIPT (0.32±0.44). There was no statistically significant difference among any of the groups or subgroups (p>0.05). ProTaper provided the smallest amount of extruded filling material, regardless of presence or absence of apical patency, followed by manual technique, without and with apical patency. Additional amounts of debris were collected during cleaning of the apical foramen, regardless of the instrument, presence/absence of patency or root filling removal technique.

Effect of smoking on cardiovascular autonomic functions

2021 ◽  
Vol 9 (2) ◽  
pp. 3780-3784
Author(s):  
P.Vani ◽  
◽  
Sharan B Singh M ◽  
Keyword(s):  
Heart Rate ◽  
Autonomic Function ◽  
T Test ◽  
Resting Heart Rate ◽  
Autonomic Functions ◽  
Mean Values ◽  
Function Tests ◽  
Significant Difference ◽  
The Mean ◽  
The Difference

Introduction: Cigarette smoking is a prime risk factor for cardiovascular morbidity and mortality. Chronic smoking results in autonomic dysfunction leading to increased cardiovascular risk in smokers. The present study was planned to study the effect of smoking on the Cardiovascular Autonomic Functions among smokers. Materials and Methods: Fifty male subjects who were in the age group of 25 to 45 years. They were grouped into 25 smokers and 25 non-smokers. The participant subjects were selected among the staff members, residents and the patients from the routine OPD in SVIMS. Prior to study, they were informed about the procedure and the purpose of the study tests and written consents were obtained from them. The Cardiovascular Autonomic Function Tests were assessed by using a POLYGRAPH which was available in the department. Results and Conclusion: After applying the ‘t’-test for the difference between the two sample means, it was observed that there was a highly significant difference between the mean values of the BMI(i.e.p<0.01) and the para-sympathetic function tests among the smokers and the non – smokers(i.e.p<0.00). The Resting Heart Rate had significantly increased and the Deep breathing difference, the postural tachycardial index (Response to standing) and the Valsalva Ratio had significantly decreased in the smokers as compared to those in the non – smokers. After applying the ‘t’-test for the difference between the two sample means, it was observed that there was no significant difference between the mean values of the Postural hypotension test (i.e. p>0.05) and that there was a highly significant difference between the mean values of the Sustained handgrip test in the smokers and the non – smokers (i.e. p<0.00). KEY WORDS: Cardiovascular autonomic function tests, Smoking, Resting heart rate.

scholarly journals A double-blind randomized controlled trial of topical Curcuma xanthorrhiza Roxb. on mild psoriasis: clinical manifestations, histopathological features, and K6 expressions

2018 ◽  
Vol 27 (3) ◽  
pp. 178-84 ◽  
Author(s):  
Githa Rahmayunita ◽  
Tjut N.A. Jacoeb ◽  
Endi Novianto ◽  
Wresti Indriatmi ◽  
Rahadi Rihatmadja ◽  
...  
Keyword(s):  
Controlled Trial ◽  
Clinical Manifestations ◽  
Effective Treatment Option ◽  
Psoriasis Area Severity Index ◽  
Double Blind ◽  
Old Patients ◽  
Mean Values ◽  
Significant Difference ◽  
Curcuma Xanthorrhiza ◽  
The Difference

Background: Curcuma xanthorrhiza Roxb. exerts its anti-inflammatory effects by reducing the concentration of IL-6, IL-8, and phosphorylase kinase, which has role in keratinocyte proliferation. Our study aimed to evaluate the efficacy of C. xanthorrhiza in psoriasis.Methods: From 18 to 59 year-old patients with mild psoriasis, 2 similar lesions were selected. The severity assessment was based on the psoriasis area severity index (PASI), Trozak score, and K6 expression. Using a double-blinded randomized method, lesion was treated with 1% C. xanthorrhiza ointment vs placebo for 4 weeks. The results were analyzed by the chi-square test using STATATM V.12 software (Stata Corp.).Results: The study was conducted in 2010 to 2012 with 17 subjects participated. The median of PASI score were reduced significantly in both lesions, either treated with 1% C. xanthorrhiza ointment vs placebo; however when compared between the group, it was not significant (p=0.520). The Trozak score were reduced in lesions treated with 1% C. xanthorrhiza ointment; but it was not significant (p = 0.306). In lesions treated with placebo, the Trozak score was increased significantly. The difference of Trozak score between lesions treated with C. xanthorrhiza and placebo was significant (p=0.024). There was no significant difference of K6 expression in lesions treated with 1% C. xanthorrhiza ointments or placebo as well as on the difference of mean values of K6 expression between the group (p=0.827).Conclusion: Based on the results, 1% C. xanthorrhiza ointment is effective treatment option for mild psoriasis, but longer follow-up period is suggested to confirm this results. C. xanthorrhiza ointment is safe for topical administration as there were no side effects reported in this study.

scholarly journals Lateral Antebrachial Cutaneous Nerve as a Donor Source for Digital Nerve Grafting: A Concept Revisited

2017 ◽  
Vol 11 (1) ◽  
pp. 1041-1048 ◽  
Author(s):  
Mehmet Bekir Unal ◽  
Kemal Gokkus ◽  
Evrim Sirin ◽  
Eren Cansü
Keyword(s):  
Pearson Correlation ◽  
Mean Value ◽  
Cutaneous Nerve ◽  
Digital Nerve ◽  
Mean Values ◽  
Nerve Grafts ◽  
The Mean ◽  
The Difference ◽  
Mean Time

Objective: The main objective of this study is to evaluate the availability of lateral antebrachial cutaneous nerve (LACN) autograft for acute or delayed repair of segmented digital nerve injuries. Patients and Methods: 13 digital nerve defects of 11 patients; treated with interposition of LACN graft that harvested from ipsilateral extremity were included in the study. Mean follow up period was 35, 7 months. The mean time from injury to grafting is 53, 3 days. The results of the mean 2PDT and SWMT values of injured /uninjured finger at the end of follow up period were evaluated with Paired T test. The correlation between the defect length and the difference of 2PDT, SWMT values between the uninjured and injured finger at the end of follow up period; were evaluated with Pearson - correlation analysis. Results: The mean value of our 2PDT and SWMT results are ~5,923, ~3, 52, respectively in which can be interpreted between the normal and diminished light touch. The defect length and difference percentage of SWMT values is positively and significantly correlated statistically. Mean length of interposed nerve grafts was 18.5 mm. The age of the patient and the mean values of 2PDT and SWMT with the difference % of 2PDT and % of SWMT are not statistically correlated. Conclusion: Based on results regarding sensory regaining at recipient side and negligible sensory deficit at harvesting side, we suggest that lateral antebrachial cutaneous nerve might be a valuable graft option for digital nerve defects.

scholarly journals Retinomotor movements in the Antarctic fish Trematomus newnesi Boulenger submitted to different environmental light conditions

2007 ◽  
Vol 24 (2) ◽  
pp. 457-462 ◽  
Author(s):  
Lucélia Donatti ◽  
Edith Fanta
Keyword(s):  
Pigment Epithelium ◽  
Antarctic Fish ◽  
Constant Darkness ◽  
Time Intervals ◽  
Mean Values ◽  
Environmental Light ◽  
The Mean ◽  
The Difference ◽  
The One ◽  
The Antarctic

The Antarctic fish Trematomus newnesi (Boulenger, 1902) occurs from benthic to pelagic habitats, in seasonally and daily varied photic conditions that induce retinomotor movements. Fish were experimentally kept under constant darkness or light, and 12Light/12Dark for seven days. The retinomotor movement of the pigment epithelium was established through the pigment index, while that of the cones was calculated as the length of the myoid. The retinomotor movement of the pigment epithelium in T.newnesi,revealed that the adaptation to constant light occurred in the one hour of exposure, remaining constant for the next seven days. However, the adaptation to constant darkness, was slower. The difference between the mean values of the pigment indices in the time intervals of sampling was significant in the first hours of the experiment, and only after six hours they were not significant any more. The myoid of cones became elongated in darkness and contracted in light. In the experiments where T.newnesiwas exposed initially to 12 hours light followed by 12 hours darkness 12 was evidenced that the speed and intensity of the retinomotor movements was higher when darkness changed into light, than when light changed into darkness.

scholarly journals Assessment of Stress Salivary Markers, Perceived Stress, and Shift Work in a Cohort of Fishermen: A Preliminary Work

2022 ◽  
Vol 19 (2) ◽  
pp. 699
Author(s):  
Roberto Zefferino ◽  
Francesca Fortunato ◽  
Addolorata Arsa ◽  
Sante Di Gioia ◽  
Gianfranco Tomei ◽  
...  
Keyword(s):  
Perceived Stress ◽  
Sleep Disturbances ◽  
Interleukin 1 ◽  
Self Esteem ◽  
Mean Values ◽  
Work Related ◽  
Work Conflict ◽  
Home Work ◽  
Physical Disorders ◽  
The Difference

Due to work-related stress, today, work itself represents a daily challenge that must be faced in many occupations. While, in the past, the scientific community has focused on the helping professions, since, an increasing number of professions have since been investigated. Therefore, different approaches exist in order to assess this disorder, representing a scientific field wherein biological and psychological dimensions both need to be evaluated. In this paper, we consider three biological salivary markers: interleukin 1 beta (IL-1β), cortisol, and melatonin. The choice derives from recent contributions to the literature in which the interplay between these markers has been verified. Briefly, such interplay could explain how the central nervous, endocrine, and immune systems communicate with each other, supporting a holistic concept of person. In 30 marine fishermen from the Apulia region of Italy, perceived stress was measured using the Professional Stress Scale (PSS) and sleep disturbances were assessed through the Pittsburgh Sleep Quality Index (PSQI). Salivary markers were collected at 8:00 a.m. and 2:00 p.m. Those subjects reporting sleep disturbance and having altered scores in two PSS subclasses, home–work conflict and self-esteem, presented inverted salivary melatonin and cortisol nictemeral rhythms (with regard to melatonin levels at 8:00 a.m., those workers reporting values higher than the median showed 64.1% versus 48.6% home–work conflict with respect to cortisol levels, subjects having an inverted circadian rhythm showed 69.9% versus 52.5% home–work conflict, and these values resulted 47.7% versus 25.3% when the self-esteem was considered). As regards melatonin, PSQI score is statistically different in the two groups of subjects as identified by median melatonin at 8:00 a.m.; specifically, the subjects who had mean values higher than the median shared higher PSQI scores (10.8 versus 9.8). The same subjects reported more frequent home–work conflict and more sleep disorders. We found a negative correlation between IL-1β at 8:00 a.m. and Cortdiff (the difference between cortisol at 8:00 a.m.–cortisol at 2:00 p.m.), and that high IL-1β at 8:00 a.m. was associated with low Cortdiff. Based on our results we would like to propose this approach in health surveillance, in order to prevent mental and/or physical disorders, however our study is surely preliminary. The interesting perspectives and hypotheses cited in this paper, in which the roles of IL-1β and norepinephrine appear central and important, could remain hypothetical if not supported by more robust observation in order to produce, truly, new knowledge. In the future we will deepen this study with a larger sample, and if these results will be confirmed, this approach could allow preventing, not only mental and physical disorders, but also immuno-mediated diseases, and, perhaps, cancer.

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