scholarly journals Impact of VOCs on the formation of ozone in a central China city during severe pollution periods

2018 ◽  
Author(s):  
Bowei Li ◽  
Steven Sai Hang Ho ◽  
Sunling Gong ◽  
Jingwei Ni ◽  
Huairui Li ◽  
...  
Keyword(s):  
Temporal Variations ◽  
Central China ◽  
Compressed Natural Gas ◽  
Pmf Model ◽  
Sampling Campaign ◽  
Time Period ◽  
Ozone Formation Potential ◽  
Range Transport ◽  
Volatile Organic ◽  
First Time

Abstract. In this work, a five-month sampling campaign was conducted for volatile organic compounds (VOCs) for the first time in Zhengzhou City, Henan province, China, where ozone (O3) pollution has shown an increasing trend in recent years. Fifty-seven VOCs defined by the Photochemical Assessment Monitoring Stations (PAMS) were sampled using canister method. Meanwhile, other O3 precursor gases were monitored online at four different sites between the time period of May–September, 2017. The results indicated that the average mixing ratio of ΣPAMS (31.57 ± 23.35 ppbv) in Zhengzhou was lower than the other megacities in China, while alkyne was in a significantly higher proportion. The abundances, compositions and ratios of PAMS showed strong spatial and temporal variations. Alkenes were the largest contributors to the ozone formation potential (OFP). On clear days, higher O3 levels were often accompanied with high ΣPAMS/NOx ratio at each site, demonstrating that the VOCs were more sensitive during the O3 formation period in Zhengzhou. Furthermore, source apportionmemt was conducted with Positive Matrix Factorization (PMF) model, and it was found that the use of compressed natural gas (CNG), the evaporation of gasoline and the exhaust from vehicles were the important sources for ambient VOCs at all four sites. Besides, the meterological conditions and long-range transport from other surrounding provinces also had an impact on the air quality determined using the cluster analysis. It is worth mentioning that the reduction in VOCs' emissions is necessary to suppress the O3 pollution.

scholarly journals Long-term measurements of ground-level ozone in Windsor, Canada – Part I. temporal variations and trends

2018 ◽  
Author(s):  
Xiaohong Xu ◽  
Tianchu Zhang ◽  
Yushan Su
Keyword(s):  
Ground Level ◽  
Temporal Variations ◽  
Control Measures ◽  
Ground Level Ozone ◽  
Ozone Formation Potential ◽  
Volatile Organic ◽  
Increasing Trend ◽  
Annual Means ◽  
Collaborative Efforts

Abstract. This study investigates temporal variations and long-term (1996–2015) trends of ground-level O3 (ozone) and its precursors, NOx (nitrogen oxides) and volatile organic compounds in Windsor, Ontario, Canada. During the 20-year study period, NOx, non-methane hydrocarbon concentrations and ozone formation potential decreased significantly by 58 %, 61 %, and 73 %, respectively, while O3 concentrations increased by 33 % (20.3 ppb in 1996 vs. 27 ppb in 2015). Our analysis revealed that the increased annual O3 concentrations in Windsor were due to (1) decreased O3 titration (by 50 % between 1996 and 2015) owing to declining nitric oxide concentrations, which is suggested by a slightly decreasing trend of annual mean total O3 concentrations after the titration effect is removed, (2) reduced local photochemical production of O3, because of dwindling precursor emissions, and (3) increased background O3 level that has more impact on the low-to-median concentrations. The net effect of those factors is decreasing peak O3 levels during the smog season from May to September, but an overall increasing trend of annual means. These results indicate that the emission control measures are effective in reducing peak ozone concentrations. However, challenges in lowering annual O3 levels call for long-term collaborative efforts in the region and around the globe.

scholarly journals Temporal variations and trend of ground-level ozone based on long-term measurements in Windsor, Canada

2019 ◽  
Vol 19 (11) ◽  
pp. 7335-7345 ◽  
Author(s):  
Xiaohong Xu ◽  
Tianchu Zhang ◽  
Yushan Su
Keyword(s):  
Ground Level ◽  
Temporal Variations ◽  
Control Measures ◽  
Ground Level Ozone ◽  
Ozone Formation Potential ◽  
Volatile Organic ◽  
Increasing Trend ◽  
Annual Means ◽  
Collaborative Efforts

Abstract. This study investigates temporal variations and long-term (1996–2015) trends of ground-level O3 (ozone) and its precursors, NOx (nitrogen oxides), and volatile organic compounds in Windsor, Ontario, Canada. During the 20-year study period, NOx, non-methane hydrocarbon concentrations, and ozone formation potential decreased significantly by 58 %, 61 %, and 73 %, respectively, while O3 concentrations increased by 33 % (20.3 ppb in 1996 vs. 27 ppb in 2015). Our analysis revealed that the increased annual O3 concentrations in Windsor were due to (1) decreased O3 titration (by 50 % between 1996 and 2015) owing to declining nitric oxide concentrations, which is suggested by a slightly decreasing trend of annual mean total O3 concentrations after the titration effect is removed, (2) reduced local photochemical production of O3 because of dwindling precursor emissions, and (3) an increased background O3 level that has a greater impact on the low-to-median concentrations. The net effect of those factors is decreasing peak O3 levels during the smog season from May to September but an overall increasing trend of annual means. These results indicate that the emission control measures are effective in reducing peak ozone concentrations. However, challenges in lowering annual O3 levels call for long-term collaborative efforts in the region and around the globe.

scholarly journals Source Apportionment of Volatile Organic Compounds (VOCs) during Ozone Polluted Days in Hangzhou, China

Atmosphere ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 780 ◽  
Author(s):  
Lixia Han ◽  
Linghong Chen ◽  
Kangwei Li ◽  
Zhier Bao ◽  
Yanyun Zhao ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Production Model ◽  
Time Interval ◽  
Secondary Source ◽  
Liquefied Petroleum Gas ◽  
Mixing Ratios ◽  
Pmf Model ◽  
Sampling Campaign ◽  
Volatile Organic

A field sampling campaign of volatile organic compounds (VOCs) was conducted during ozone polluted days at three sites of botanic gardens (HP), industrial areas (XS), and traffic residential mixed areas (ZH) in Hangzhou. The sampling was performed using stainless steel canisters from 6:00 to 20:00 synchronously with a time interval of 2 h on 17 May, 26 June, 20 July, 24 August, and 26 September 2018. A total of 107 species of VOCs for each sample were quantified using two standard gases with a pre-concentrator coupled by GC/MS. The Positive Matrix Factorization (PMF) model was used to identify the major VOC sources and assess their contribution to VOC concentrations. The effects of VOCs on O3 formation were investigated, based on propylene-equivalent concentrations (Prop-E), ozone formation potential (OFP), and Smog Production Model (SPM). It was found that the concentration of ozone during the sampling days tended to be highest in the downwind area while the concentrations of VOCs and NO2 in HP were rather low. The most reactive species were isoprene, ethylene, m-xylene, toluene, and propylene. The average total VOC volume mixing ratios in HP, XS, and ZH were 32.00, 36.63, and 50.34 ppbv, respectively. Bimodal profiles of propane and n-butane were exhibited in ZH while unimodal diurnal variation of isoprene was performed in HP. Liquefied petroleum gas/natural gas (LPG/NG) usage, aged background, and secondary source were identified as the major contributors to total VOCs in Hangzhou, accounting for 19.65%, 15.53%, and 18.93%, respectively.

scholarly journals Allelopathic Effect of Serphidium kaschgaricum (Krasch.) Poljak. Volatiles on Selected Species

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 495
Author(s):  
Shixing Zhou ◽  
Toshmatov Zokir ◽  
Yu Mei ◽  
Lijing Lei ◽  
Kai Shi ◽  
...  
Keyword(s):  
Volatile Compounds ◽  
Volatile Oil ◽  
Amaranthus Retroflexus ◽  
Allelopathic Effect ◽  
Chemical Profile ◽  
Volatile Oils ◽  
Phytotoxic Activity ◽  
Volatile Organic ◽  
First Time ◽  
Stem Leaf

The chemical profile and allelopathic effect of the volatile organic compounds (VOCs) produced by a dominant shrub Serphidium kaschgaricum (Krasch.) Poljak. growing in northwestern China was investigated for the first time. Serphidium kaschgaricu was found to release volatile compounds into the surroundings to affect other plants’ growth, with its VOCs suppressing root elongation of Amaranthus retroflexus L. and Poa annua L. by 65.47% and 60.37% at 10 g/1.5 L treatment, respectively. Meanwhile, volatile oils produced by stems, leaves, flowers and flowering shoots exhibited phytotoxic activity against A. retroflexus and P. annua. At 0.5 mg/mL, stem, leaf and flower oils significantly reduced seedling growth of the receiver plants, and 1.5 mg/mL oils nearly completely prohibited seed germination of both species. GC/MS analysis revealed that among the total 37 identified compounds in the oils, 19 of them were common, with eucalyptol (43.00%, 36.66%, 19.52%, and 38.68% in stem, leaf, flower and flowering shoot oils, respectively) and camphor (21.55%, 24.91%, 21.64%, and 23.35%, respectively) consistently being the dominant constituents in all oils. Eucalyptol, camphor and their mixture exhibited much weaker phytotoxicity compared with the volatile oils, implying that less abundant compounds in the volatile oil might contribute significantly to the oils’ activity. Our results suggested that S. kaschgaricum was capable of synthesizing and releasing allelopathic volatile compounds into the surroundings to affect neighboring plants’ growth, which might improve its competitiveness thus facilitate the establishment of dominance.

scholarly journals Fast and Reliable Multiresidue Analysis of Aromas in Wine by Means of Gas Chromatography Coupled with Triple Quadrupole Mass Spectrometry

Analytica ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 38-49
Author(s):  
Ettore Guerriero ◽  
Massimo Iorizzo ◽  
Marina Cerasa ◽  
Ivan Notardonato ◽  
Bruno Testa ◽  
...  
Keyword(s):  
Direct Injection ◽  
Headspace Analysis ◽  
White Wine ◽  
Quadrupole Mass ◽  
Multiresidue Analysis ◽  
Liquid Liquid Extraction ◽  
Volatile Organic ◽  
Steel Tank ◽  
First Time

The paper would like to show a direct injection into GC-MS/QqQ for the determination of secondary aromas in white wine samples fermented in two different ways. The procedure has been compared with more traditional methods used in this field, i.e., headspace analysis and liquid–liquid extraction. The application of such direct injection, for the first time in the literature, allows us to analyze Volatile Organic Compounds (VOCs) in the range 0.1–100 µg mL−1, with Limits of Detection (LODs) and Limits of Quantification (LOQs) between 0.01–0.05 µg mL−1 and 0.03–0.09 µg mL−1, respectively, intraday and interday below 5.6% and 8.5%, respectively, and recoveries above 92% at two different fortification levels. The procedure has been applied to real wine samples: it evidences how the fermentation in wood (cherry) barrel yields higher VOC levels than ones in wine fermented in steel tank, causing production of different secondary aromas and different relative flavors.

scholarly journals Hydrostatic Densitometer for Monitoring Density in Freshwater to Hypersaline Water Bodies

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1842
Author(s):  
Ziv Mor ◽  
Hallel Lutzky ◽  
Eyal Shalev ◽  
Nadav G. Lensky
Keyword(s):  
Continuous Monitoring ◽  
Pressure Sensors ◽  
Temporal Variations ◽  
Dead Sea ◽  
Conductivity Measurements ◽  
Lake Levels ◽  
Density Profiles ◽  
Water Column Stratification ◽  
Hypersaline Water ◽  
First Time

Density, temperature, salinity, and hydraulic head are physical scalars governing the dynamics of aquatic systems. In coastal aquifers, lakes, and oceans, salinity is measured with conductivity sensors, temperature is measured with thermistors, and density is calculated. However, in hypersaline brines, the salinity (and density) cannot be determined by conductivity measurements due to its high ionic strength. Here, we resolve density measurements using a hydrostatic densitometer as a function of an array of pressure sensors and hydrostatic relations. This system was tested in the laboratory and was applied in the Dead Sea and adjacent aquifer. In the field, we measured temporal variations of vertical profiles of density and temperature in two cases, where water density varied vertically from 1.0 × 103 kg·m−3 to 1.24 × 103 kg·m−3: (i) a borehole in the coastal aquifer, and (ii) an offshore buoy in a region with a diluted plume. The density profile in the borehole evolved with time, responding to the lowering of groundwater and lake levels; that in the lake demonstrated the dynamics of water-column stratification under the influence of freshwater discharge and atmospheric forcing. This method allowed, for the first time, continuous monitoring of density profiles in hypersaline bodies, and it captured the dynamics of density and temperature stratification.

scholarly journals Condensation/immersion mode ice-nucleating particles in a boreal environment

2020 ◽  
Vol 20 (11) ◽  
pp. 6687-6706
Author(s):  
Mikhail Paramonov ◽  
Saskia Drossaart van Dusseldorp ◽  
Ellen Gute ◽  
Jonathan P. D. Abbatt ◽  
Paavo Heikkilä ◽  
...  
Keyword(s):  
Field Campaign ◽  
Particle Species ◽  
Entire Field ◽  
Time Period ◽  
Regional Sources ◽  
Range Transport ◽  
Thermodynamic Conditions ◽  
Set Up ◽  
Boreal Environment ◽  
Measurement Location

Abstract. Ice-nucleating particle (INP) measurements were performed in the boreal environment of southern Finland at the Station for Measuring Ecosystem–Atmosphere Relations (SMEAR II) in the winter–spring of 2018. Measurements with the Portable Ice Nucleation Chamber (PINC) were conducted at 242 K and 105 % relative humidity with respect to water. The median INP number concentration [INP] during a 6-week measurement period was 13 L−1. The [INP] spanned 3 orders of magnitude and showed a general increase from mid-February until early April. No single dominant local or regional sources of INPs in the boreal environment of southern Finland could be identified. Rather, it is hypothesised that the INPs detected at SMEAR II are a result of long-range transport and dilution of INPs sourced far from the measurement site. Despite high variability, the measured [INP] values fall within the range expected for the [INP] measured elsewhere under similar thermodynamic conditions. The [INP] did not correlate with any of the examined parameters during the entire field campaign, indicating that no one single parameter can be used to predict the [INP] at the measurement location during the examined time period. The absence of a correlation across the entire field campaign also suggests that a variety of particles act as INPs at different times, although it was indirectly determined that ambient INPs are most likely within the size range of 0.1–0.5 µm in diameter on average. On shorter timescales, several particle species correlated well with the [INP]. Depending on the meteorological conditions, black carbon (BC), supermicron biological particles and sub-0.1 µm particles, most likely nanoscale biological fragments such as ice-nucleating macromolecules (INMs), correlated with the INP signal. However, an increase in the concentration of any of these particle species may not necessarily lead to the increase in the [INP]; the reasons for this remain unknown. Limitations of the instrumental set-up and the necessity for future field INP studies are addressed.

scholarly journals Carbon monoxide (CO) and ethane (C<sub>2</sub>H<sub>6</sub>) trends from ground-based solar FTIR measurements at six European stations, comparison and sensitivity analysis with the EMEP model

2011 ◽  
Vol 11 (17) ◽  
pp. 9253-9269 ◽  
Author(s):  
J. Angelbratt ◽  
J. Mellqvist ◽  
D. Simpson ◽  
J. E. Jonson ◽  
T. Blumenstock ◽  
...  
Keyword(s):  
Transport Model ◽  
Global Scale ◽  
Global Model ◽  
Scale Model ◽  
Chemical Transport Model ◽  
Suitable Alternative ◽  
European Model ◽  
Time Period ◽  
Volatile Organic ◽  
Made In

Abstract. Trends in the CO andC2H6 partial columns ~0–15 km) have been estimated from four European ground-based solar FTIR (Fourier Transform InfraRed) stations for the 1996–2006 time period. The CO trends from the four stations Jungfraujoch, Zugspitze, Harestua and Kiruna have been estimated to −0.45 ± 0.16% yr−1, −1.00 ± 0.24% yr−1, −0.62 ± 0.19 % yr−1 and −0.61 ± 0.16% yr−1, respectively. The corresponding trends for C2H6 are −1.51 ± 0.23% yr−1, −2.11 ± 0.30% yr−1, −1.09 ± 0.25% yr−1 and −1.14 ± 0.18% yr−1. All trends are presented with their 2-σ confidence intervals. To find possible reasons for the CO trends, the global-scale EMEP MSC-W chemical transport model has been used in a series of sensitivity scenarios. It is shown that the trends are consistent with the combination of a 20% decrease in the anthropogenic CO emissions seen in Europe and North America during the 1996–2006 period and a 20% increase in the anthropogenic CO emissions in East Asia, during the same time period. The possible impacts of CH4 and biogenic volatile organic compounds (BVOCs) are also considered. The European and global-scale EMEP models have been evaluated against the measured CO and C2H6 partial columns from Jungfraujoch, Zugspitze, Bremen, Harestua, Kiruna and Ny-Ålesund. The European model reproduces, on average the measurements at the different sites fairly well and within 10–22% deviation for CO and 14–31% deviation for C2H6. Their seasonal amplitude is captured within 6–35% and 9–124% for CO and C2H6, respectively. However, 61–98% of the CO and C2H6 partial columns in the European model are shown to arise from the boundary conditions, making the global-scale model a more suitable alternative when modeling these two species. In the evaluation of the global model the average partial columns for 2006 are shown to be within 1–9% and 37–50% of the measurements for CO and C2H6, respectively. The global model sensitivity for assumptions made in this paper is also analyzed.

The Relationship Between City “Greenness” and Homicide in the US: Evidence Over a 30-Year Period

2021 ◽  
pp. 001391652110450
Author(s):  
Jonnell C. Sanciangco ◽  
Gregory D. Breetzke ◽  
Zihan Lin ◽  
Yuhao Wang ◽  
Kimberly A. Clevenger ◽  
...  
Keyword(s):  
Violent Crime ◽  
P Value ◽  
Homicide Rates ◽  
Violence Reduction ◽  
Time Period ◽  
The Us ◽  
Longitudinal Effects ◽  
Curve Modeling ◽  
First Time ◽  
Us Cities

Residents in US cities are exposed to high levels of stress and violent crime. At the same time, a number of cities have put forward “greening” efforts which may promote nature’s calming effects and reduce stressful stimuli. Previous research has shown that greening may lower aggressive behaviors and violent crime. In this study we examined, for the first time, the longitudinal effects over a 30-year period of average city greenness on homicide rates across 290 major cities in the US, using multilevel linear growth curve modeling. Overall, homicide rates in US cities decreased over this time-period (52.1–33.5 per 100,000 population) while the average greenness increased slightly (0.41–0.43 NDVI). Change in average city greenness was negatively associated with homicide, controlling for a range of variables (β = −.30, p-value = .02). The results of this study suggest that efforts to increase urban greenness may have small but significant violence-reduction benefits.

scholarly journals Revision of the pollen beetle genus Meligethes (Coleoptera: Nitidulidae)

2014 ◽  
Vol 46 (1-2) ◽  
pp. 19 ◽  
Author(s):  
Paolo Audisio ◽  
Simone Sabatelli ◽  
Josef Jelìnek
Keyword(s):  
Taxonomic Revision ◽  
Central China ◽  
Pollen Beetle ◽  
Sw China ◽  
Species Complexes ◽  
Western Palearctic ◽  
Specific Rank ◽  
Species Groups ◽  
Available Information ◽  
First Time

A taxonomic revision of members of the genus <em>Meligethes</em> Stephens, 1830 is carried out. Taxonomic and distributional notes are provided on fiftythree <em>Meligethes</em> species, mostly known from the Eastern Palearctic and marginally from the Western Palearctic and the Oriental Regions. Among these, twentythree new species of <em>Meligethes</em> are diagnosed, figured and described: <em>M</em>. <em>argentithorax</em> sp. n. (Central China: Shaanxi, Shanxi), <em>M</em>. <em>aurantirugosus</em> sp. n. (Nepal),<em> M. aureolineatus</em> sp. n. (Central China: Sichuan), <em>M. aurifer</em> sp. n. (Central China: Shaanxi, Shanxi), <em>M. brassicogethoides</em> sp. n. (SW China: Yunnan), <em>M. clinei</em> sp. n. (SW China: Yunnan), <em>M. elytralis</em> sp. n. (Central China: Sichuan), <em>M. ferruginoides</em> sp. n. (Central China: Sichuan), <em>M.</em> <em>cinereoargenteus</em> sp. n. (Central China: Sichuan), <em>M. henan</em> sp. n. (Central China: Henan), <em>M. luteoornatus</em> sp. n. (SW China: Yunnan), <em>M. marmota</em> sp. n. (Nepal), <em>M. nivalis</em> sp. n. (SW and central China: Xizang and Chongqing), <em>M. martes</em> sp. n. (Central China: Shaanxi, Shanxi, Sichuan), <em>M. nigroaeneus</em> sp. n. (SW China: Yunnan), <em>M. occultus</em> sp. n. (SW China: Yunnan), <em>M</em>. <em>pseudochinensis</em> sp. n. (Central China: Hubei), <em>M. pseudopectoralis</em> sp. n. (SW China: Yunan),<em> M. schuelkei</em> sp. n. (Central China: Sichuan, Shaanxi), <em>M. simulator</em> sp. n. (Central-N China: Shanxi), <em>M. stenotarsus</em> sp. n. (SW China: Yunnan, Xizang), <em>M. tryznai</em> sp. n. (SW China: Yunnan), and <em>M. volkovichi</em> sp. n. (SW China: Yunnan). Revaluations at specific rank from synonymy are introduced for <em>Meligethes lutra</em> Solsky 1860, and for <em>M. melleus</em> Grouvelle, 1908. Three new synonymies are established: <em>Meligethes brevipilus</em> Kirejtshuk, 1980 = <em>M. auripilis</em> Reitter, 1889 (syn. n.), <em>Meligethes zakharenkoi</em> Kirejtshuk, 2005 = <em>M. shirakii</em> Sadanari Hisamatsu, 1956 (syn. n.), and <em>Meligethes shirozui</em> Sadanari Hisamatsu, 1965 =<em> M. wagneri</em> Rebmann, 1956 (syn. n.). Complete redescriptions are given for <em>Meligethes binotatus</em> Grouvelle, 1894, <em>M. castanescens</em> Grouvelle, 1903, <em>M. ferrugineus</em> Reitter, 1873, and <em>M. melleus</em> Grouvelle, 1908. The male of <em>Meligethes lloydi</em> Easton, 1968, is described and figured for the first time. The female genitalia of <em>Meligethes auricomus</em> Rebmann, 1956, <em>M. cinereus</em> Jelínek, 1978, and <em>M. griseus</em> Jelínek, 1978 are described and figured for the first time. Available information on insect-host-plant relationships and ecology are summarized for each species; probably all are associated as larvae with flowers of Rosaceae, chiefly of members of the closely related genera <em>Rosa</em> L., <em>Rubus</em> L., <em>Prunus</em> L., and <em>Crataegus</em> Tourn. ex L. All treated species are grouped in two here revaluated subgenera (<em>Meligethes</em> s.str. and <em>Odonthogethes</em> Reitter, 1871), and tentatively grouped also in species-groups and (when necessary) species-complexes, based on their morphology.

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