scholarly journals Observation of nitrate dominant PM<sub>2.5</sub> and particle pH elevation in urban Beijing during the winter of 2017

2019 ◽  
Author(s):  
Yuning Xie ◽  
Gehui Wang ◽  
Xinpei Wang ◽  
Jianmin Chen ◽  
Yubao Chen ◽  
...  
Keyword(s):  
Average Concentration ◽  
Molar Ratio ◽  
Effective Control ◽  
Nitrate Content ◽  
Low Level ◽  
Secondary Formation ◽  
Sulfur Emission ◽  
History Record ◽  
Future Prediction ◽  
Major Chemical

Abstract. Particle acidity is crucial to understand secondary formation processes in pollution events because of its substantial impacts on the physiochemical properties of PM2.5. Recently, particle pH predicted by thermodynamic modeling were used to elucidate the sulfate formation mechanism in China, but the results were biased and controversial. In this article, particle pH was found to be increase as a result of effective sulfur emission control. Benefit from strict pollution control actions, average PM2.5 concentration reduced to a low level (39.7 μg/m3) in urban Beijing during winter of 2017. Compare to history record (2014–2017), SO2 gradually decreased to a low level (3.2 ppbv in 2017 winter) while NO2 kept increasing (21.4 ppbv in 2017 winter). As a response, nitrate's contribution (23.0 μg/m3) to PM2.5 become dominant over sulfate (13.1 μg/m3) during the PM2.5 pollution. The nitrate to sulfate molar ratio significantly increased from 1 to 2.7 (value of 1999 and 2017). As particulate nitrate fraction significantly elevated, particle pH was also found to increase in winter Beijing given sufficient ammonia (average concentration 7.1 μg/m3, 12.9 μg/m3 during pollution). During PM2.5 pollution episodes, the particle pH predicted increased from 4.4 (moderate acidic) to 5.4 (near neutral) as nitrate to sulfate molar ratio increased from 1 to 5. It is found that the major H+ contributor S(VI) was mostly in the form of sulfate, showing anions were more neutralized as nitrate content enriched. In the final part, future prediction of particle acidity change was discussed via sensitivity tests: On one hand, nitrate rich particles would absorb more water compared to the sulfate rich particles. This absorption contrast doubles with low to moderate RH (20 % ~ 50 %). On the other hand, increased level of nitrate and ammonia would have synergetic effects leading to rapid elevation of particle pH to merely neutral (above 5.6). As moderate haze might occur more frequently with high ammonia and particulate nitrate concentration, the major chemical processes during haze events and the control target shall be re-evaluated to obtain the most effective control strategy.

scholarly journals Nitrate-dominated PM<sub>2.5</sub> and elevation of particle pH observed in urban Beijing during the winter of 2017

2020 ◽  
Vol 20 (8) ◽  
pp. 5019-5033 ◽  
Author(s):  
Yuning Xie ◽  
Gehui Wang ◽  
Xinpei Wang ◽  
Jianmin Chen ◽  
Yubao Chen ◽  
...  
Keyword(s):  
Atmospheric Aerosols ◽  
Ammonia Concentration ◽  
Historical Record ◽  
Molar Ratio ◽  
Effective Control ◽  
Nitrate Content ◽  
Chinese Government ◽  
Low Level ◽  
The Impact ◽  
Pollution Episodes

Abstract. The Chinese government has exerted strict emission controls to mitigate air pollution since 2013, which has resulted in significant decreases in the concentrations of air pollutants such as SO2. Strict pollution control actions also reduced the average PM2.5 concentration to the low level of 39.7 µg m−3 in urban Beijing during the winter of 2017. To investigate the impact of such changes on the physiochemical properties of atmospheric aerosols in China, we conducted a comprehensive observation focusing on PM2.5 in Beijing during the winter of 2017. Compared with the historical record (2014–2017), SO2 decreased to the low level of 3.2 ppbv in the winter of 2017, but the NO2 level was still high (21.4 ppbv in the winter of 2017). Accordingly, the contribution of nitrate (23.0 µg m−3) to PM2.5 far exceeded that of sulfate (13.1 µg m−3) during the pollution episodes, resulting in a significant increase in the nitrate-to-sulfate molar ratio. The thermodynamic model (ISORROPIA II) calculation results showed that during the PM2.5 pollution episodes particle pH increased from 4.4 (moderate acidic) to 5.4 (more neutralized) when the molar ratio of nitrate to sulfate increased from 1 to 5, indicating that aerosols were more neutralized as the nitrate content elevated. Controlled variable tests showed that the pH elevation should be attributed to nitrate fraction increase other than crustal ion and ammonia concentration increases. Based on the results of sensitivity tests, future prediction for the particle acidity change was discussed. We found that nitrate-rich particles in Beijing at low and moderate humid conditions (RH: 20 %–50 %) can absorb twice the amount of water that sulfate-rich particles can, and the nitrate and ammonia with higher levels have synergetic effects, rapidly elevating particle pH to merely neutral (above 5.6). As moderate haze events might occur more frequently under abundant ammonia and nitrate-dominated PM2.5 conditions, the major chemical processes during haze events and the control target should be re-evaluated to obtain the most effective control strategy.

scholarly journals Yield and Quality Characteristics of Brassica Microgreens as Affected by the NH4:NO3 Molar Ratio and Strength of the Nutrient Solution

Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 677 ◽  
Author(s):  
Onofrio Davide Palmitessa ◽  
Massimiliano Renna ◽  
Pasquale Crupi ◽  
Angelo Lovece ◽  
Filomena Corbo ◽  
...  
Keyword(s):  
Nutrient Solution ◽  
Inorganic Ions ◽  
Molar Ratio ◽  
High Yield ◽  
Nitrate Content ◽  
Carotene Content ◽  
Molar Ratios ◽  
Half Strength ◽  
Nutrient Solutions ◽  
Β Carotene

Microgreens are gaining more and more interest, but little information is available on the effects of the chemical composition of the nutrient solution on the microgreen yield. In this study, three Brassica genotypes (B. oleracea var. italica, B. oleracea var. botrytis, and Brassica rapa L. subsp. sylvestris L. Janch. var. esculenta Hort) were fertigated with three modified strength Hoagland nutrient solutions (1/2, 1/4, and 1/8 strength) or with three modified half-strength Hoagland nutrient solutions with three different NH4:NO3 molar ratios (5:95, 15:85, and 25:75). Microgreen yields and content of inorganic ions, dietary fiber, proteins, α-tocopherol, and β-carotene were evaluated. Micro cauliflower showed the highest yield, as well as a higher content of mineral elements and α-tocopherol (10.4 mg 100 g−1 fresh weight (FW)) than other genotypes. The use of nutrient solution at half strength gave both a high yield (0.23 g cm−2) and a desirable seedling height. By changing the NH4:NO3 molar ratio in the nutrient solution, no differences were found on yield and growing parameters, although the highest β-carotene content (6.3 mg 100 g−1 FW) was found by using a NH4:NO3 molar ratio of 25:75. The lowest nitrate content (on average 6.8 g 100 g−1 dry weight) was found in micro broccoli and micro broccoli raab by using a nutrient solution with NH4:NO3 molar ratios of 25:75 and 5:95, respectively. Micro cauliflower fertigated with a NH4:NO3 molar ratio of 25:75 showed the highest dry matter (9.8 g 100 g−1 FW) and protein content (4.2 g 100 g−1 FW).

Polyelectrolyte-Enhanced Ultrafiltration (PEUF) Process for Low Level Arsenic Removal: Recovery of Polyelectrolyte from Retentate Stream

2012 ◽  
Vol 506 ◽  
pp. 27-30 ◽  
Author(s):  
P. Pookrod ◽  
W. Dungkaew ◽  
P. Un-Arn ◽  
K.J. Haller
Keyword(s):  
Arsenic Removal ◽  
Concentration Level ◽  
Divalent Cations ◽  
Cationic Polyelectrolyte ◽  
Molar Ratio ◽  
Contaminated Water ◽  
Process Technology ◽  
Low Level ◽  
Low Levels ◽  
Size And Morphology

Removal of low levels of arsenic from contaminated water using the polyelectrolyte-enhanced ultrafiltration or PEUF process technology has been studied. The cationic polyelectrolyte poly (diallyldimethyl ammonium chloride), PDADMAC, was utilized to bind arsenic (in the form of arsenate anion) in contaminated water and the polyelectrolyte-arsenate complex solution was then filtered off (as retentate) by ultrafiltration. The 99-99.9% arsenic removal from synthetic low level arsenic (100 ppb) contaminated water demonstrates that the technology can easily achieve the relatively new international arsenic maximum concentration level of 10 ppb. To make the PEUF process more economical and environmentally friendly, the PDADMAC in the retentate must be recovered. Precipitation of PDADMAC-arsenate solutions with divalent cations has been studied to separate out metal-arsenate compounds leaving free PDADMAC to reuse in the process. The metal-arsenate compound precipitation is strongly affected by divalent metal:As molar ratio, and pH of the solution. The precipitation results also suggest that polyelectrolyte retards formation of the metal-arsenate compounds and affects the size and morphology of the particles formed, thus directly affecting the sedimentation rate of the resulting precipitate.

Growth and Terpenoid Production of an Axenic Culture from the Liverwort Ricciocarpos natans

1990 ◽  
Vol 45 (1-2) ◽  
pp. 13-18 ◽  
Author(s):  
Gerald Wurzel ◽  
Hans Becker
Keyword(s):  
Light Intensity ◽  
Nitrogen Source ◽  
Axenic Culture ◽  
Light Regime ◽  
Culture Period ◽  
Molar Ratio ◽  
Nitrate Content ◽  
The Media

Abstract Ricciocarpos natans grows best on Gamborg B5 medium supplemented with 2% sucrose. Six other mineral media were less effective on the growth. During a culture period, pH of the media changed depending on the ammonium and nitrate content of the respective media. In media of a molar ratio of ammonium to nitrate of 1:1 or 1:1.9, pH first dropped from 6.0 to about 3.5 and then rose again. In media where nitrate is the only nitrogen source or where there is a ratio of ammonium to nitrate of 1:12.5, pH rose during the first two weeks and after this dropped. Differences in the light intensity (2000 an d 6000 lx) and light regime (14 h light/ 10 h dark) had no effects on the growth. The cultures produced a variety of terpenoids. The same pattern of compounds was seen in field-collected material as well as in cultivated material. The content of the terpenoids decreased on nitrogen and phosphorous-deficient media.

scholarly journals Primary and secondary sources of ambient formaldehyde in the Yangtze River Delta based on Ozone Mapping and Profiler Suite (OMPS) observations

2019 ◽  
Vol 19 (10) ◽  
pp. 6717-6736 ◽  
Author(s):  
Wenjing Su ◽  
Cheng Liu ◽  
Qihou Hu ◽  
Shaohua Zhao ◽  
Youwen Sun ◽  
...  
Keyword(s):  
Cancer Risk ◽  
Yangtze River ◽  
Yangtze River Delta ◽  
River Delta ◽  
Effective Control ◽  
The Yangtze River ◽  
Secondary Sources ◽  
Secondary Formation ◽  
The Yrd ◽  
The Yangtze River Delta

Abstract. Formaldehyde (HCHO) in the ambient air not only causes cancer but is also an ideal indicator of volatile organic compounds (VOCs), which are major precursors of ozone (O3) and secondary organic aerosol (SOA) near the surface. It is meaningful to differentiate between the direct emission and the secondary formation of HCHO for HCHO pollution control and sensitivity studies of O3 production. However, understanding of the sources of HCHO is still poor in China, due to the scarcity of field measurements (both spatially and temporally). In this study, tropospheric HCHO vertical column densities (VCDs) in the Yangtze River Delta (YRD), East China, where HCHO pollution is serious, were retrieved from the Ozone Mapping and Profiler Suite (OMPS) onboard the Suomi National Polar-orbiting Partnership (Suomi-NPP) satellite from 2014 to 2017; these retrievals showed good agreement with the tropospheric HCHO columns measured using ground-based high-resolution Fourier transform infrared spectrometry (FTS) with a correlation coefficient (R) of 0.78. Based on these results, the cancer risk was estimated both nationwide and in the YRD region. It was calculated that at least 7840 people in the YRD region would develop cancer in their lives due to outdoor HCHO exposure, which comprised 23.4 % of total national cancer risk. Furthermore, the contributions of primary and secondary sources were apportioned, in addition to primary and secondary tracers from surface observations. Overall, the HCHO from secondary formation contributed most to ambient HCHO and can be regarded as the indicator of VOC reactivity in Hangzhou and in urban areas of Nanjing and Shanghai from 2015 to 2017, due to the strong correlation between total HCHO and secondary HCHO. At industrial sites in Nanjing, primary emissions more strongly influenced ambient HCHO concentrations in 2015 and showed an obvious decreasing trend. Seasonally, HCHO from secondary formation reached a maximum in summer and a minimum in winter. In the spring, summer, and autumn, secondary formation had a significant effect on the variation of ambient HCHO in urban regions of Nanjing, Hangzhou, and Shanghai, whereas in the winter the contribution from secondary formation became less significant. A more thorough understanding of the variation of the primary and secondary contributions of ambient HCHO is needed to develop a better knowledge regarding the role of HCHO in atmospheric chemistry and to formulate effective control measures to decrease HCHO pollution and the associated cancer risk.

scholarly journals Contributing factors that influence on road traffic’s risk

2020 ◽  
Vol 11 (3) ◽  
pp. 75-80
Author(s):  
I. O. Kolosok ◽  
Keyword(s):  
Road Safety ◽  
Local Governments ◽  
Safety Management ◽  
Action Plan ◽  
Road Transport ◽  
Integrated System ◽  
Effective Control ◽  
Negative Consequences ◽  
Road Accidents ◽  
Low Level

The level of transport at safety, energy consumption, and impact on the environment in Ukraine do not meet modern requirements. In recent decades, the world has seen a sharp increase in the number of vehicles and an increase in traffic, which leads to a stolen increase in the number of traffic accidents and their negative consequences. There is a whole range of issues that need to be solved, such as high mortality and injury rates as a result of road accidents; a significant part of obsolete vehicles operated by Ukrainian carrier, that is inefficient and harm the environment; the imperfection of the transport safety management system and the absence of a single coordinating body for road safety management, which is the reason for the lack of an integrated system of state road safety management; low level of coordination of actions and institutional capacity of state authorities and local governments to plan and conduct actions in the field of road safety; the imperfection of traffic accident monitoring systems, their statistics, and risk management; ineffective approach in solving the problem of high accident rate and severity of its consequences and creating a scientific basis for activities in the field of road safety; lack of specific measurable goals to increase the level of road safety, the relevant coordinated action plan in this area; unsatisfactory technical condition of a significant number of vehicles and the lack of a system for monitoring the safety of vehicles during their operation; low level of introduction and practical application of the latest technologies and technical means of traffic organization, automated means of control and regulation of traffic; insufficient funding of measures aimed at preventing and reducing the level of accidents, reducing the number of road accidents with real consequences; low level of driver training and lack of effective control over the activities of driving schools; low level of education of the society in the field of road safety, own responsibility and observance of traffic rules, etc. The car has advantages over other types of vehicles: high mobility, relative ease of operation, the ability to deliver passengers and goods "door to door". It is these advantages of the car that are associated with the negative phenomena that accompany motorization where the lack of traffic safety is in the first place. We can name three important characteristics of modern road transport, which determine the low-level of safety: insufficient provision of road transport with appropriate in their parameters roads; insufficient isolation of traffic flows from other road users; mass driver's profession, which causes a low average level of qualification.

scholarly journals Agroindustrial complex: problems and instigating trends

2021 ◽  
pp. 22-28
Author(s):  
Lyudmila Anatol'evna Zhuravleva
Keyword(s):  
Rural Areas ◽  
Agricultural Production ◽  
Adult Population ◽  
Developed Countries ◽  
Government Support ◽  
Effective Control ◽  
Small Scale ◽  
Investment Activity ◽  
Low Level ◽  
Agroindustrial Complex

The article analyzes the current problems, functional strategies and instigating trends of the agroindustrial complex. The author describes the possible ways of solving problems and considers the prospects for the development of small-scale enterprises based on the existing government support programs for rural areas. Among the most acute problems for the successful development of farms, the author identifies the following groups of problems: 1. Economic problems: rising prices for fuels and lubricants; the volatility of the ruble exchange rate; the constant increase in tariffs for gas, electricity, fertilizers, machinery for agricultural production; the disproportion of prices of products and resources spent on their production; the lack of long-term supportive programs of preferential lending and leasing services; low level of innovation and investment activity; low level of solvency of the population; unsatisfactory state of telephone and Internet communications, roads and transport links; monopolization of sales markets by large agricultural holdings; insufficient development of marketing and logistics issues; weak image advertising of farm products and the lack of integrated marketing communications, which reduce the profitability and profitability of agricultural production. 2. Technological problems: technical and technological lagging behind the developed countries; low technological efficiency of agricultural production of peasant farms; a high degree of deterioration of the equipment and machinery. 3. Ecological problems: industrial and agricultural enterprises impacting on the environment; the inrease in land fertility; the use of pesticides leading to soil and water pollution; the lack of effective control over the quality and safety of food. 4. Social problems of rural areas: the lack of educational institutions with educational services of high quality and developed infrastructure; the lack of jobs for the adult population and youth's low interest in farming as a way of life; domestic problems.&nbsp;

scholarly journals Total mercury and selenium concentrations in Sarpa salpa and Balistes capriscus and in their respective Digenean endoparasites Robphildollfusium fractum and Neoapocreadium chabaudi from Tunisia

2014 ◽  
Vol 59 (4) ◽  
Author(s):  
Jordi Torres ◽  
Hichem Kacem ◽  
Catarina Eira ◽  
Lassad Neifar ◽  
Jordi Miquel
Keyword(s):  
Average Concentration ◽  
Molar Ratio ◽  
The European Union ◽  
Potential Health ◽  
Molar Ratios ◽  
Balistes Capriscus ◽  
Se:Hg Molar Ratio ◽  
Biomonitoring Tool ◽  
Sarpa Salpa ◽  
Hg Pollution

AbstractThe present study reports the levels of mercury and selenium in Sarpa salpa and Balistes capriscus collected along the coast of Mahdia and Sfax (Tunisia). The systems constituted by S. salpa and Robphildollfusium fractum and by B. capriscus and Neoapocreadium chabaudi were tested as potential bioindicators to monitor environmental Hg pollution in marine ecosystems. Mercury and selenium concentrations were assessed in kidney, liver and muscle of 51 S. salpa and of 45 B. capriscus as well as in their respective endoparasites R. fractum and N. chabaudi. The Se:Hg molar ratios were evaluated for both species across the study areas. Surprisingly, the Se:Hg molar ratio in B. capriscus muscle from Mahdia is significantly lower than in Sfax. Our results indicate that some parasites may also be implicated in the amount of Se and Hg available in tissues and therefore contribute to oscillations of the Se:Hg molar ratios. In the model involving the carnivorous species (B. capriscus), the 5.1-times higher levels of mercury in N. chabaudi than in B. capriscus muscle in Sfax enable this fluke to be a sensitive biomonitoring tool for Hg pollution. The present results confirm that the habitual consumption of S. salpa should not suppose any potential health risk for Tunisian people. On the other hand, the consumption of B. capriscus may be of concern and further monitoring is advisable, since the Hg average concentration in Mahdia was above the maximum allowed Hg concentration in the edible portion of fish fixed by the European Union.

scholarly journals Estimation of Selected Minerals in Aortic Aneurysms—Impaired Ratio of Zinc to Lead May Predispose?

2020 ◽  
Author(s):  
Katarzyna Socha ◽  
Alicja Karwowska ◽  
Adam Kurianiuk ◽  
Renata Markiewicz-Żukowska ◽  
Andrzej Guzowski ◽  
...  
Keyword(s):  
Aortic Aneurysm ◽  
Aortic Wall ◽  
Average Concentration ◽  
Aortic Aneurysms ◽  
Molar Ratio ◽  
Control Group ◽  
Tissue Samples ◽  
Abdominal Aortic ◽  
Mineral Components ◽  
Cadmium And Lead

Abstract The objective of this study was to estimate the content of copper, zinc, selenium, cadmium, and lead in the tissue of patients with aortic aneurysms. Molar ratio of Cu/Zn and antioxidant micronutrients to toxic elements was also calculated. A total of 108 patients: 47 with abdominal aortic aneurysm (AAA), 61 patients with thoracic aortic aneurysm (TAA), and a control group of 20 abdominal aortic (AA) and 20 thoracic aortic (TA) wall samples from the deceased were studied. The concentrations of mineral components in the tissue samples were determined by the AAS method. The average concentration of Cu in the aortic wall of patients with TAA was significantly lower than in the aortic wall samples of healthy people. The mean concentration of Zn in the aortic wall of patients with AAA and TAA was significantly lower than in the control group samples. Cu/Zn ratio was significantly higher in AAA patients than in control group which indicates a greater role of oxidative stress and inflammatory process in this type of aneurysm. The concentration of Se was significantly decreased in TAA patients compared with the control group; in turn, the concentration of Pb was increased in this group of patients. We observed significantly lower Cu/Pb ratio in TAA patients than in control group, whereas Zn/Pb ratio was significantly lower comparing with control samples in both types of aneurysms. In the examined aneurysms, we have shown the differences in concentrations of mineral components compared with the control tissues. The Zn concentration was decreased in both AAA and TAA samples. Impaired ratio of Zn to Pb may predispose to aortic aneurysms.

scholarly journals Observation-Based Summer O3 Control Effect Evaluation: A Case Study in Chengdu, a Megacity in Sichuan Basin, China

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1278
Author(s):  
Qinwen Tan ◽  
Li Zhou ◽  
Hefan Liu ◽  
Miao Feng ◽  
Yang Qiu ◽  
...  
Keyword(s):  
Control Period ◽  
Photochemical Reactions ◽  
Control Measures ◽  
Effective Control ◽  
Industrial Emissions ◽  
Transport Channel ◽  
Photochemical Pollution ◽  
Control Policies ◽  
Secondary Formation ◽  
Vehicular Exhaust

Ground-level ozone (O3), which is mainly from the photochemical reactions of NOx and volatile organic compounds (VOCs), has become a crucial pollutant obstructing air quality improvement in China. Understanding the composition, temporal variability and source apportionment of VOCs is necessary for determining effective control measures to minimize VOCs and their related photochemical pollution. To provide a comprehensive analysis of VOC sources and their contributions to ozone formation in the city of Chengdu—a megacity with the highest rates of industrial and economic development in southwest China—we conducted a one-month monitoring project at three urban sites (Shuangliu, Xindu, Junpingjie; SL, XD and JPJ, respectively) along the main north–south meteorological transport channel before and during the implemented control measures. Alkanes were the dominant group at each site, contributing to around 50% of the observed total VOCs, followed by oxygen-containing VOCs (OVOCs), aromatics, halohydrocarbons and alkenes. During the control period, the mixing ratios of most measured VOC species decreased, and O3 concentrations were down by at least 20%. VOC species experiencing the most effect from control were aromatics and OVOCs, which had higher O3 formation reactivity. This indicated that the control policies had significant influence on reductions of reactive VOC species. We also identified VOC sources at SL and XD using positive matrix factorization (PMF) and assessed their contributions to photochemical O3 formation by calculating the O3 formation potential (OFP) based on mass concentrations and maximum incremental reactivity of related VOCs. Five dominant VOC sources were identified, with the highest contributions from vehicular exhaust and fuel evaporation before control, followed by solvent utilization, biogenic background and secondary formation, and industrial emissions. Contribution from vehicular exhaust was reduced the most at SL, while at XD, secondary formation VOCs decreased significantly. VOCs from vehicular and industrial emissions and solvent utilization were found to be the dominant precursors for OFPs, particularly the species of xylenes, toluene and propene. Our results therefore suggest that priority should be given to the alleviation of photochemical pollutants for effective control of O3 formation in Chengdu. The findings from this work have important implications for formulating effective emission control policies in Chengdu.

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