scholarly journals Direct observations indicate photodegradable oxygenated VOCs as larger contributors to radicals and ozone production in the atmosphere

2021 ◽  
Author(s):  
Wenjie Wang ◽  
Bin Yuan ◽  
Yuwen Peng ◽  
Hang Su ◽  
Yafang Cheng ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Southern China ◽  
Control Strategies ◽  
Proton Transfer Reaction ◽  
Mitigation Strategies ◽  
Ozone Production ◽  
Effective Control ◽  
Measurement Technology ◽  
Ozone Formation ◽  
Secondary Sources

Abstract. Volatile organic compounds (VOCs) regulate atmospheric oxidation capacity, and the reactions of VOCs are key in understanding ozone formation and its mitigation strategies. When evaluating its impact, most previous studies did not fully consider the role of oxygenated VOCs due to limitations of measurement technology. By using a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) combined with gas chromatography mass spectrometer (GC-MS) technology, we are able to quantify a large number of oxygenated VOCs in a representative urban environment in southern China. Based on the new dataset, we find that non – formaldehyde (HCHO) OVOCs can contribute large fractions (22–44 %) of total ROX radical production, comparable or larger than the contributions from nitrous acid and formaldehyde. We demonstrate that constraints using OVOCs observations are essential in modeling radical and ozone production, as modelled OVOCs can be substantially lower than measurements, potentially due to primary emissions and/or missing secondary sources. Our results show that models without OVOC constraints using ambient measurements will underestimate P(ROX) and ozone production rate, and may also affect the determination of sensitivity regime in ozone formation. Therefore, a thorough quantification of photodegradable OVOCs species is in urgent need to understand accurately the ozone chemistry and to develop effective control strategies.

OH reactivity in three major city clusters of China in ozone seasons: insights for regional ozone formation

2020 ◽  
Author(s):  
Shengrong Lou ◽  
Xiangsen Shen ◽  
Xin Li ◽  
Qian Wang ◽  
Shuoying Liu
Keyword(s):  
Control Strategies ◽  
Ambient Air ◽  
Ozone Production ◽  
Trace Gas ◽  
Ozone Formation ◽  
Oh Radical ◽  
Ozone Pollution ◽  
Major City ◽  
Photochemical Process

<p><span>OH radical is the key driver of the photochemical process and closely related to ozone formation. OH reactivity is the quantification of OH radical sink in ambient air. In this study, in-situ OH reactivity measurements are carried out in Shenzhen, Chengdu and Changzhou, three typical cities in major city clusters of China, during their ozone pollution seasons. The measured OH reactivity is ranging from 5~35 s-1 under various meteorological conditions and trace gas concentrations. Aldehydes such as HCHO and acetaldehyde, mainly from the secondary formation of VOCs, are the principal contributors at day time. Primary VOCs such as toluene and biogenic VOCs such as isoprene play different roles in three measurement locations. The missing OH reactivity, which is defined as the OH reactivity that cannot be explained by trace gas measurements, are evaluated by in-situ measurement results as well as an observation-based model. Gas-phase secondary pollutants could be the main source of the missing OH reactivity. The sensitivity tests by the OBM model show ozone production in all areas is mainly VOC-limited but the key precursors of ozone are not identical, leading to different control strategies.</span></p>

scholarly journals Persistent growth of anthropogenic NMVOC emissions in China during 1990–2017: dynamics, speciation, and ozone formation potentials

2019 ◽  
Author(s):  
Meng Li ◽  
Qiang Zhang ◽  
Bo Zheng ◽  
Dan Tong ◽  
Yu Lei ◽  
...  
Keyword(s):  
Control Strategies ◽  
Industrial Sector ◽  
Control Measures ◽  
Tropospheric Chemistry ◽  
Anthropogenic Sources ◽  
Effective Control ◽  
Ozone Formation ◽  
Ozone Pollution ◽  
Industry Sector ◽  
Solvent Use

Abstract. Non-methane volatile organic compounds (NMVOC) are important ozone and secondary organic aerosol precursors and play important roles in tropospheric chemistry. In this work, we estimated the total and speciated NMVOC emissions from China’s anthropogenic sources during 1990–2017 by using a bottom-up emission inventory framework, and investigated the main drivers behind the trends. We found that, anthropogenic NMVOC emissions in China have been increased continuously since 1990 due to the dramatic growth in activity rates and absence of effective control measures. We estimated that, anthropogenic NMVOC emissions in China increased from 9.76 Tg in 1990 to 28.5 Tg in 2017, mainly driven by persistent growth from the industry sector and solvent use. In the meanwhile, emissions from the residential and transportation sectors declined after 2005, partly offset the total emission increase. During 1990–2017, mass-based emissions of alkanes, alkenes, alkynes, aromatics, oxygenated VOCs (OVOC) and other species increased by 274 %, 88 %, 4 %, 387 %, 91 %, and 231 % respectively. Following the growth in total NMVOC emissions, the corresponding ozone formation potential (OFP) increased form 38.2 Tg-O3 in 1990 to 99.7 Tg-O3 in 2017. We estimated that aromatics accounted for the largest share (43 %) of total OFP, followed by alkenes (37 %) and OVOC (10 %). Growth in China's NMVOC emissions were mainly driven by the transportation sector before 2000, while industrial sector and solvent use dominated the emission growth during 2000–2010. After 2010, although emissions from the industry sector and solvent use kept growing, strict control measures on transportation and fuel transition in residential stoves have successfully slowed down the increase trend, especially after the implementation of China's clean air action since 2013. However, compared to large emission decreases of other criteria air pollutants in China (e.g., SO2, NOx, and primary PM) during 2013–2017, the relatively flat trend in NMVOC emissions and OFP revealed the absence of effective control measures, which might have contributed to the increase of ozone during the same period. Given their high contributions to emissions and OFP, tailored control measures for solvent use and industrial sources should be developed, and collaborative control strategies should be designed to mitigate both PM2.5 and ozone pollution simultaneously.

scholarly journals Modeling Peste des Petits Ruminants (PPR) Disease Propagation and Control Strategies Using Memoryless State Transitions

2017 ◽  
Vol 1 (2) ◽  
pp. 90 ◽  
Author(s):  
Michael D. Mitchell ◽  
Walter E. Beyeler ◽  
Patrick Finley ◽  
Melissa Finley DVM, PhD
Keyword(s):  
Empirical Data ◽  
Large Scale ◽  
Control Strategies ◽  
Mitigation Strategies ◽  
Sensitivity Analyses ◽  
Effective Control ◽  
State Transitions ◽  
Morbidity Rate ◽  
Peste Des Petits Ruminants ◽  
And Control

<p><em>Peste des Petits Ruminants (PPR) is an infectious disease affecting goats and sheep. PPR has a mortality rate of 80% and a morbidity rate of 100% in naïve herds. This disease is currently of concern to Afghani goat and sheep herders as conditions in Afghanistan are conducive to the disease becoming an epidemic. PPR is similar to Rinderpest, but is not as well studied. There is a lack of empirical data on how the disease spreads or effective large-scale mitigation strategies. We developed a herd-level, event-driven model of PPR, using memoryless state transitions, to study how the virus propagates through a herd, and to identify effective control strategies for disparate herd configurations and environments. This model allows us to perform Sensitivity Analyses (SA) on environmental and disease parameters for which we do not have empirical data and to simulate the effectiveness of various control strategies. We find that reducing the amount of time from the identification of PPR in a herd to the vaccination of the herd will radically reduce the number of deaths that result from PPR. The goal of this model is to give policy makers a tool to develop effective containment strategies for managing outbreaks of PPR.</em></p>

scholarly journals Marine Organisms for the Sustainable Management of Plant Parasitic Nematodes

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 369
Author(s):  
Pasqua Veronico ◽  
Maria Teresa Melillo
Keyword(s):  
Crop Production ◽  
Control Strategies ◽  
Marine Organisms ◽  
New Drugs ◽  
Effective Control ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Wide Range ◽  
Plant Growth Stimulants ◽  
Plant Parasitic

Plant parasitic nematodes are annually responsible for the loss of 10%–25% of worldwide crop production, most of which is attributable to root-knot nematodes (RKNs) that infest a wide range of agricultural crops throughout the world. Current nematode control tools are not enough to ensure the effective management of these parasites, mainly due to the severe restrictions imposed on the use of chemical pesticides. Therefore, it is important to discover new potential nematicidal sources that are suitable for the development of additional safe and effective control strategies. In the last few decades, there has been an explosion of information about the use of seaweeds as plant growth stimulants and potential nematicides. Novel bioactive compounds have been isolated from marine cyanobacteria and sponges in an effort to find their application outside marine ecosystems and in the discovery of new drugs. Their potential as antihelmintics could also be exploited to find applicability against plant parasitic nematodes. The present review focuses on the activity of marine organisms on RKNs and their potential application as safe nematicidal agents.

scholarly journals Label-Free Comparative Proteomics of Differentially Expressed Mycobacterium tuberculosis Protein in Rifampicin-Related Drug-Resistant Strains

Pathogens ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 607
Author(s):  
Nadeem Ullah ◽  
Ling Hao ◽  
Jo-Lewis Banga Ndzouboukou ◽  
Shiyun Chen ◽  
Yaqi Wu ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Drug Targets ◽  
Control Strategies ◽  
Multidrug Resistant ◽  
Differentially Expressed ◽  
Effective Control ◽  
Drug Resistant ◽  
Differentially Expressed Proteins ◽  
Label Free ◽  
Candidate Target

Rifampicin (RIF) is one of the most important first-line anti-tuberculosis (TB) drugs, and more than 90% of RIF-resistant (RR) Mycobacterium tuberculosis clinical isolates belong to multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB. In order to identify specific candidate target proteins as diagnostic markers or drug targets, differential protein expression between drug-sensitive (DS) and drug-resistant (DR) strains remains to be investigated. In the present study, a label-free, quantitative proteomics technique was performed to compare the proteome of DS, RR, MDR, and XDR clinical strains. We found iniC, Rv2141c, folB, and Rv2561 were up-regulated in both RR and MDR strains, while fadE9, espB, espL, esxK, and Rv3175 were down-regulated in the three DR strains when compared to the DS strain. In addition, lprF, mce2R, mce2B, and Rv2627c were specifically expressed in the three DR strains, and 41 proteins were not detected in the DS strain. Functional category showed that these differentially expressed proteins were mainly involved in the cell wall and cell processes. When compared to the RR strain, Rv2272, smtB, lpqB, icd1, and folK were up-regulated, while esxK, PPE19, Rv1534, rpmI, ureA, tpx, mpt64, frr, Rv3678c, esxB, esxA, and espL were down-regulated in both MDR and XDR strains. Additionally, nrp, PPE3, mntH, Rv1188, Rv1473, nadB, PPE36, and sseA were specifically expressed in both MDR and XDR strains, whereas 292 proteins were not identified when compared to the RR strain. When compared between MDR and XDR strains, 52 proteins were up-regulated, while 45 proteins were down-regulated in the XDR strain. 316 proteins were especially expressed in the XDR strain, while 92 proteins were especially detected in the MDR strain. Protein interaction networks further revealed the mechanism of their involvement in virulence and drug resistance. Therefore, these differentially expressed proteins are of great significance for exploring effective control strategies of DR-TB.

scholarly journals The use of light spectrum blocking films to reduce populations of Drosophila suzukii Matsumura in fruit crops

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Michelle T. Fountain ◽  
Amir Badiee ◽  
Sebastian Hemer ◽  
Alvaro Delgado ◽  
Michael Mangan ◽  
...  
Keyword(s):  
Control Strategies ◽  
Field Trials ◽  
Biological Data ◽  
Insect Vision ◽  
Invasive Pest ◽  
Effective Control ◽  
Fruit Crops ◽  
Light Spectrum ◽  
Drosophila Suzukii ◽  
The Impact

Abstract Spotted wing drosophila, Drosophila suzukii, is a serious invasive pest impacting the production of multiple fruit crops, including soft and stone fruits such as strawberries, raspberries and cherries. Effective control is challenging and reliant on integrated pest management which includes the use of an ever decreasing number of approved insecticides. New means to reduce the impact of this pest that can be integrated into control strategies are urgently required. In many production regions, including the UK, soft fruit are typically grown inside tunnels clad with polyethylene based materials. These can be modified to filter specific wavebands of light. We investigated whether targeted spectral modifications to cladding materials that disrupt insect vision could reduce the incidence of D. suzukii. We present a novel approach that starts from a neuroscientific investigation of insect sensory systems and ends with infield testing of new cladding materials inspired by the biological data. We show D. suzukii are predominantly sensitive to wavelengths below 405 nm (ultraviolet) and above 565 nm (orange & red) and that targeted blocking of lower wavebands (up to 430 nm) using light restricting materials reduces pest populations up to 73% in field trials.

scholarly journals Enhanced SOA formation from mixed anthropogenic and biogenic emissions during the CARES campaign

2013 ◽  
Vol 13 (4) ◽  
pp. 2091-2113 ◽  
Author(s):  
J. E. Shilling ◽  
R. A. Zaveri ◽  
J. D. Fast ◽  
L. Kleinman ◽  
M. L. Alexander ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Organic Aerosol ◽  
Proton Transfer Reaction ◽  
Chemical Mechanism ◽  
Biogenic Emissions ◽  
Anthropogenic Emissions ◽  
Radiation Balance ◽  
Particle Phase ◽  
Aerosol Formation ◽  
Research Aircraft

Abstract. The CARES campaign was conducted during June, 2010 in the vicinity of Sacramento, California to study aerosol formation and aging in a region where anthropogenic and biogenic emissions regularly mix. Here, we describe measurements from an Aerodyne High Resolution Aerosol Mass Spectrometer (AMS), an Ionicon Proton Transfer Reaction Mass Spectrometer (PTR-MS), and trace gas detectors (CO, NO, NOx) deployed on the G-1 research aircraft to investigate ambient gas- and particle-phase chemical composition. AMS measurements showed that the particle phase is dominated by organic aerosol (OA) (85% on average) with smaller concentrations of sulfate (5%), nitrate (6%) and ammonium (3%) observed. PTR-MS data showed that isoprene dominated the biogenic volatile organic compound concentrations (BVOCs), with monoterpene concentrations generally below the detection limit. Using two different metrics, median OA concentrations and the slope of plots of OA vs. CO concentrations (i.e., ΔOA/ΔCO), we contrast organic aerosol evolution on flight days with different prevailing meteorological conditions to elucidate the role of anthropogenic and biogenic emissions on OA formation. Airmasses influenced predominantly by biogenic emissions had median OA concentrations of 2.2 μg m−3 and near zero ΔOA/ΔCO. Those influenced predominantly by anthropogenic emissions had median OA concentrations of 4.7 μg m−3 and ΔOA/ΔCO ratios of 35–44 μg m−3 ppmv. But, when biogenic and anthropogenic emissions mixed, OA levels were enhanced, with median OA concentrations of 11.4 μg m−3 and ΔOA/ΔCO ratios of 77–157 μg m−3 ppmv. Taken together, our observations show that production of OA was enhanced when anthropogenic emissions from Sacramento mixed with isoprene-rich air from the foothills. After considering several anthropogenic/biogenic interaction mechanisms, we conclude that NOx concentrations play a strong role in enhancing SOA formation from isoprene, though the chemical mechanism for the enhancement remains unclear. If these observations are found to be robust in other seasons and in areas outside of Sacramento, regional and global aerosol modules will need to incorporate more complex representations of NOx-dependent SOA mechanisms and yields into their algorithms. Ultimately, accurately predicting OA mass concentrations and their effect on radiation balance will require a mechanistically-based treatment of the interactions of biogenic and anthropogenic emissions.

Surveillance-based estimation of the malaria disease burden in a low endemic state of Punjab, India, targeted for malaria elimination

2021 ◽  
Author(s):  
Jaspreet Kaur ◽  
Taruna Kaura ◽  
Ayush Sharma ◽  
Ashish Kumar ◽  
M K Pangotra ◽  
...  
Keyword(s):  
Malaria Elimination ◽  
Control Strategies ◽  
The State ◽  
Primary Data ◽  
Effective Control ◽  
Malaria Surveillance ◽  
Weighted Estimates ◽  
Malaria Burden ◽  
Routine Surveillance ◽  
Malaria Trends

Abstract Background The state of Punjab in India qualifies for malaria elimination because the number of cases reported through routine surveillance is in decline. However, surveillance system prevalence mainly provides malaria trends. Therefore, a prospective epidemiological study was designed to estimate the malaria burden in the state. Methods District-wise annual parasite incidence (API) was used for identification of three strata, representing high, moderate and low API zones. A total of 0.9 million people from nine districts was under malaria surveillance for 1 y. The weighted estimates of API for the three regions was calculated and combined to give an estimate of API for the total population of the state. Results Based upon the primary data generated, malaria cases from high, moderate and low malaria-endemic areas were estimated to be 3727, 904 and 106, respectively. Further, the total number of malaria cases in the state was estimated to be 4737 (95% CI 4006 to 5469) cases per annum. Conclusion Actual burden of malaria in the state of Punjab, India, is about seven to eight times higher than that reported by routine surveillance activities. However, the state still qualifies for malaria elimination but needs vigorous efforts to strengthen the active surveillance and reporting system along with implementation of effective control strategies to achieve malaria elimination.

Ozone Photochemistry in New York City and Baltimore based on Aircraft Observations

2021 ◽  
Author(s):  
Xinrong Ren ◽  
Phillip Stratton ◽  
Hannah Daley ◽  
Russell Dickerson
Keyword(s):  
New York ◽  
New York City ◽  
York City ◽  
Production Efficiency ◽  
Control Strategies ◽  
Scientific Information ◽  
Photochemical Oxidation ◽  
Ozone Production ◽  
Source Regions ◽  
Aircraft Observations

&lt;p&gt;Aircraft observations of ozone, ozone precursors, and meteorological parameters were made over the New York City (NYC) and Baltimore areas during ozone exceedance events in summer 2018-2020.&amp;#160; Despite the continued reduction in anthropogenic emissions, ozone exceedance events still frequently occurred in the NYC area.&amp;#160; Ozone production efficiency, defined as the ratio of the ozone production rate to the NO&lt;sub&gt;x&lt;/sub&gt; oxidation rate, calculated using these observations,&amp;#160; was about 14 ppb ozone produced per ppb NOx oxidized. This high ozone production efficiency likely contributes to the persistent ozone exceedance problem over the Long Island Sound and Connecticut coastal area, downwind of NYC under prevailing southwesterly winds.&amp;#160; There is some evidence for a decreasing trend although COVID-19 restrictions had an impact on 2020 emissions.&amp;#160; A box model, constrained by observations, was used to examine atmospheric photochemical oxidation processes.&amp;#160; Ozone production rates and their sensitivity to nitrogen oxides (NO&lt;sub&gt;x&lt;/sub&gt;) and volatile organic compounds (VOCs) were calculated based on the model results. In general ozone production is VOC sensitive near emission sources and NOx sensitive away from source regions. While the Baltimore area is predominantly in the NOx sensitive region, the NYC area is transitioning from VOC sensitive to NOx sensitive.&amp;#160; Preliminary results show that controlling both NOx and VOCs reduces ozone production in the NYC area. Reducing VOCs can reduce ozone production in emission source regions and reducing NOx can reduce ozone production farther away from the source regions. The results from this work strengthen our understanding of ozone production and provide scientific information for emission control strategies to reduce air pollution in ozone non-attainment areas.&lt;/p&gt;

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