scholarly journals Role of ammonia on fine-particle pH in agricultural regions of China: Comparison between urban and rural sites

2019 ◽  
Author(s):  
Shenbo Wang ◽  
Lingling Wang ◽  
Yuqing Li ◽  
Chen Wang ◽  
Weisi Wang ◽  
...  
Keyword(s):  
Ph Value ◽  
Fundamental Property ◽  
High Ph ◽  
Sensitivity Tests ◽  
High Ammonia ◽  
Haze Episode ◽  
Rural Sites ◽  
Agricultural Regions ◽  
Urban Sites

Abstract. Particle acidity is a fundamental property that affects atmospheric particulate chemistry. Synchronous online monitoring was performed in two urban sites (e.g., Zhengzhou (U-ZZ) and Anyang (U-AY)) and three rural sites (e.g., Anyang (R-AY), Xinxiang (R-XX), and Puyang (R-PY)) in Henan Province during a haze episode to investigate the pH value and its driving factors in the agricultural regions of China. The pH values of particles calculated by ISORROPIA-II model at rural sites were slightly higher than those urban sites, with the median values in the order of 5.2 (4.8–6.9, R-PY) > 5.1 (4.7–6.5, R-AY) > 4.9 (4.1–6.8, R-XX) > 4.8 (3.9–5.9, U-AY) > 4.5 (3.8–5.2, U-ZZ). Sensitivity tests showed that excess ammonia mainly affected the pH value of PM2.5. Moreover, low ammonia determined the high sensitivities of particle pH to sulfate and nitrate at urban sites. Elevated sulfate and nitrate in aerosol caused high pH sensitivity to ammonia. Regional transport may enhance the particle pH value in urban aerosols given the high pH of particles and high ammonia levels in rural and agricultural regions. These results suggest that ammonia is urgently needed to be involved in the regional strategy for the improvement of air quality in China.

scholarly journals Effect of ammonia on fine-particle pH in agricultural regions of China: comparison between urban and rural sites

2020 ◽  
Vol 20 (5) ◽  
pp. 2719-2734 ◽  
Author(s):  
Shenbo Wang ◽  
Lingling Wang ◽  
Yuqing Li ◽  
Chen Wang ◽  
Weisi Wang ◽  
...  
Keyword(s):  
Ph Value ◽  
Fundamental Property ◽  
Chemical Components ◽  
Air Masses ◽  
Ph Values ◽  
Rural Sites ◽  
Total Ammonium ◽  
Total Sulfate ◽  
Agricultural Regions ◽  
Urban Sites

Abstract. Particle acidity is a fundamental property that affects atmospheric particulate chemistry. Synchronous online monitoring was performed at two urban sites, Zhengzhou (U-ZZ) and Anyang (U-AY), and three rural sites, Anyang (R-AY), Xinxiang (R-XX), and Puyang (R-PY) in Henan Province, during a haze episode to investigate the pH value and its driving factors in the agricultural regions of China. The pH values of particles calculated by ISORROPIA-II model at rural sites were slightly higher than those at urban sites, with the median (min–max) values of 5.2 (4.8–6.9, R-PY), 5.1 (4.7–6.5, R-AY), 4.9 (4.1–6.8, R-XX), 4.8 (3.9–5.9, U-AY), and 4.5 (3.8–5.2, U-ZZ). Sensitivity tests show that TNHx (total ammonium, gas + aerosol) followed by total sulfate were the most important factors that influenced the predicted pH. Generally, particle pH increased with a cation increase and decreases in anions, temperature, and relative humidity. Similar pH values (∼3.0) at the required NHx concentrations for the five sites indicated that the presence of excess NHx was likely important for the lower acidity of PM2.5 during the severe haze episodes in this region. Moreover, the concentrations of excess NHx may drive the higher pH values at rural sites, because of the higher excess NHx concentrations at rural sites than those at urban sites. The underlying influence of regional transport on local particle pH cannot be neglected, as it differs the chemical components of PM2.5 and meteorological conditions. Air masses transported from rural and agricultural regions may enhance the particle pH value in urban aerosols given the high pH of particles and high ammonia levels. These results suggest that ammonia is urgently needed to be involved in the regional strategy for the improvement of air quality in China.

scholarly journals Assessment of COVID-19 Lockdown Impact on the Air Quality in Eastern Spain: PM and BTX in Urban, Suburban and Rural Sites Exposed to Different Emissions

Atmosphere ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 97
Author(s):  
Milagros Ródenas ◽  
Rubén Soler ◽  
Esther Borrás ◽  
Teresa Vera ◽  
José Jaime Diéguez ◽  
...  
Keyword(s):  
Air Quality ◽  
Meteorological Parameters ◽  
Control Strategies ◽  
Air Pollution Control ◽  
Benzene Toluene ◽  
Rural Sites ◽  
The Impact ◽  
Urban Sites

In early 2020, the COVID-19 pandemic spread globally, and severe measures to control it were implemented. This study investigates the impact of the lockdown on the air quality of three provinces in the Valencia region, eastern Spain, in the years 2015–2020, focusing on particulate matter (PM). A thorough statistical analysis using different approaches is conducted. Hourly patterns are also assessed. In addition, the role of meteorological parameters on PM is explored. The results indicate an overall PM10 reduction of 16.5% when comparing the lockdown in 2020 and the 2015–2019 period, while PM2.5 increased by 3.1%. As expected, urban zones experienced higher reductions than suburban zones, which experienced a PM concentration increase. The impact of the drastic drops of benzene, toluene and xylene (77.4%, 58.0% and 61.8%, respectively) on the PM values observed in urban sites is discussed. Our study provides insights on the effect of activity changes over a wide region covering a variety of air quality stations, urban, suburban and rural, and different emission types. The results of this work are a valuable reference and suggest the need for considering different factors when establishing scientific air pollution control strategies.

The orientation of sickle hemoglobin fibers within fascicles

1988 ◽  
Vol 46 ◽  
pp. 400-401
Author(s):  
Christopher A. Miller ◽  
Bridget Carragher ◽  
William A. McDade ◽  
Robert Josephs
Keyword(s):  
Sickle Cell ◽  
Sickle Cell Anemia ◽  
Relative Orientation ◽  
Unit Cell ◽  
Red Cell ◽  
High Ph ◽  
Sickle Hemoglobin ◽  
Polar Crystal ◽  
Helical Configuration

Highly ordered bundles of deoxyhemoglobin S (HbS) fibers, termed fascicles, are intermediates in the high pH crystallization pathway of HbS. These fibers consist of 7 Wishner-Love double strands in a helical configuration. Since each double strand has a polarity, the odd number of double strands in the fiber imparts a net polarity to the structure. HbS crystals have a unit cell containing two double strands, one of each polarity, resulting in a net polarity of zero. Therefore a rearrangement of the double strands must occur to form a non-polar crystal from the polar fibers. To determine the role of fascicles as an intermediate in the crystallization pathway it is important to understand the relative orientation of fibers within fascicles. Furthermore, an understanding of fascicle structure may have implications for the design of potential sickling inhibitors, since it is bundles of fibers which cause the red cell distortion responsible for the vaso-occlusive complications characteristic of sickle cell anemia.

scholarly journals EPID-07. ACCESS TO GLIOBLASTOMA CLINICAL TRIALS FOR RURAL PATIENTS IN THE UNITED STATES FROM 2010–2020

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii79-ii79
Author(s):  
Kathryn Nevel ◽  
Samuel Capouch ◽  
Lisa Arnold ◽  
Katherine Peters ◽  
Nimish Mohile ◽  
...  
Keyword(s):  
United States ◽  
Clinical Trials ◽  
Rural Communities ◽  
The United States ◽  
Interventional Treatment ◽  
Phase Ii Trials ◽  
Treatment Trials ◽  
Rural Sites ◽  
Rural Patients ◽  
Urban Sites

Abstract BACKGROUND Patients in rural communities have less access to optimal cancer care and clinical trials. For GBM, access to experimental therapies, and consideration of a clinical trial is embedded in national guidelines. Still, the availability of clinical trials to rural communities, representing 20% of the US population, has not been described. METHODS We queried ClinicalTrials.gov for glioblastoma interventional treatment trials opened between 1/2010 and 1/2020 in the United States. We created a Structured Query Language database and leveraged Google application programming interfaces (API) Places to find name and street addresses for the sites, and Google’s Geocode API to determine the county location. Counties were classified by US Department of Agriculture Rural-Urban Continuum Codes (RUCC 1–3 = urban and RUCC 4–9 = rural). We used z-ratios for rural-urban statistical comparisons. RESULTS We identified 406 interventional treatment trials for GBM at 1491 unique sites. 8.7% of unique sites were in rural settings. Rural sites opened an average of 1.7 trials/site and urban sites 2.8 trials/site from 1/2010–1/2020. Rural sites offered more phase II trials (63% vs 57%, p= 0.03) and fewer phase I trials (22% vs 28%, p= 0.01) than urban sites. Rural locations were more likely to offer federally-sponsored trials (p< 0.002). There were no investigator-initiated or single-institution trials offered at rural locations, and only 1% of industry trials were offered rurally. DISCUSSION Clinical trials for GBM were rarely open in rural areas, and were more dependent on federal funding. Clinical trials are likely difficult to access for rural patients, and this has important implications for the generalizability of research as well as how we engage the field of neuro-oncology and patient advocacy groups in improving patient access to trials. Increasing the number of clinical trials in rural locations may enable more rural patients to access and enroll in GBM studies.

scholarly journals Overcoming ammonia inhibition in anaerobic blackwater treatment with granular activated carbon: the role of electroactive microorganisms

2019 ◽  
Vol 5 (2) ◽  
pp. 383-396 ◽  
Author(s):  
Anna Patrícya Florentino ◽  
Ahmed Sharaf ◽  
Lei Zhang ◽  
Yang Liu
Keyword(s):  
Activated Carbon ◽  
Hydrogen Exchange ◽  
Granular Activated Carbon ◽  
Ammonia Concentration ◽  
Anaerobic Digesters ◽  
Ammonia Inhibition ◽  
High Ammonia

Methanogenesis and enrichment of microorganisms capable of interspecies electron and/or hydrogen exchange was investigated with addition of granular activated carbon (GAC) to batch anaerobic digesters treating vacuum collected blackwater with high ammonia concentration.

The role of calcium in high pH excursions for reactivated GAC

Carbon ◽  
2005 ◽  
Vol 43 (3) ◽  
pp. 511-518 ◽  
Author(s):  
David W. Mazyck ◽  
Fred S. Cannon ◽  
Morgana T. Bach ◽  
Ljubisa R. Radovic
Keyword(s):  
High Ph

scholarly journals The role of transition metal ions on HO<sub>x</sub> radicals in clouds: a numerical evaluation of its impact on multiphase chemistry

2004 ◽  
Vol 4 (1) ◽  
pp. 95-110 ◽  
Author(s):  
L. Deguillaume ◽  
M. Leriche ◽  
A. Monod ◽  
N. Chaumerliac
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Aqueous Phase ◽  
Numerical Evaluation ◽  
Transition Metal Ions ◽  
Cloud Chemistry ◽  
Sensitivity Tests ◽  
Fe Speciation ◽  
Deposition Processes

Abstract. A new modelling study of the role of transition metal ions on cloud chemistry has been performed. Developments of the Model of Multiphase Cloud Chemistry (M2C2; Leriche et al., 2001) are described, including the transition metal ions reactivity emission/deposition processes and variable photolysis in the aqueous phase. The model is then applied to three summertime scenarios under urban, remote and marine conditions, described by Ervens et al. (2003). Chemical regimes in clouds are analyzed to understand the role of transition metal ions on cloud chemistry and especially, on HxOy chemistry, which consequently influences the sulphur and the VOCs chemistry in droplets. The ratio of Fe(II)/Fe(III) exhibits a diurnal variation with values in agreement with the available measurements of Fe speciation. In the urban case, sensitivity tests with and without TMI chemistry, show an enhancement of OH concentration in the aqueous phase when TMI chemistry is considered.

scholarly journals Column aerosol optical properties and aerosol radiative forcing during a serious haze-fog month over North China Plain in 2013 based on ground-based sunphotometer measurements

2013 ◽  
Vol 13 (11) ◽  
pp. 29685-29720 ◽  
Author(s):  
H. Che ◽  
X. Xia ◽  
J. Zhu ◽  
Z. Li ◽  
O. Dubovic ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
North China Plain ◽  
North China ◽  
Optical Parameters ◽  
Aerosol Radiative Forcing ◽  
Coarse Mode ◽  
Fine Mode ◽  
Rural Sites ◽  
Urban Sites ◽  
Aerosol Radiative

Abstract. In January 2013, North China Plain experienced several serious haze events. Cimel sunphotometer measurements at seven sites over rural, suburban and urban regions of North China Plain from 1 to 30 January 2013 were used to further our understanding of spatial-temporal variation of aerosol optical parameters and aerosol radiative forcing (ARF). It was found that Aerosol Optical Depth at 500 nm (AOD500 nm) during non-pollution periods at all stations was lower than 0.30 and increased significantly to greater than 1.00 as pollution events developed. The Angstrom exponent (Alpha) was larger than 0.80 for all stations most of the time. AOD500 nm averages increased from north to south during both polluted and non-polluted periods on the three urban sites in Beijing. The fine mode AOD during pollution periods is about a factor of 2.5 times larger than that during the non-pollution period at urban sites but a factor of 5.0 at suburban and rural sites. The fine mode fraction of AOD675 nm was higher than 80% for all sites during January 2013. The absorption AOD675 nm at rural sites was only about 0.01 during pollution periods, while ~0.03–0.07 and 0.01–0.03 during pollution and non-pollution periods at other sites, respectively. Single scattering albedo varied between 0.87 and 0.95 during January 2013 over North China Plain. The size distribution showed an obvious tri-peak pattern during the most serious period. The fine mode effective radius in the pollution period was about 0.01–0.08 μm larger than during non-pollution periods, while the coarse mode radius in pollution periods was about 0.06–0.38 μm less than that during non-pollution periods. The total, fine and coarse mode particle volumes varied by about 0.06–0.34 μm3, 0.03–0.23 μm3, and 0.03–0.10 μm3, respectively, throughout January 2013. During the most intense period (1–16 January), aerosol radiative forcing (ARF) at the surface exceeded −50 W m−2, −180 W m−2, and −200 W m−2 at rural, suburban, and urban sites, respectively. The ARF readings at the top of the atmosphere were approximately −30 W m−2 in rural and −40–60 W m−2 in urban areas. Positive ARF at the top of the atmosphere at the Huimin suburban site was found to be different from others as a result of the high surface albedo due to snow cover.

scholarly journals Measurements of ozone and its precursors in Beijing during summertime: impact of urban plumes on ozone pollution in downwind rural areas

2011 ◽  
Vol 11 (23) ◽  
pp. 12241-12252 ◽  
Author(s):  
J. Xu ◽  
J. Z. Ma ◽  
X. L. Zhang ◽  
X. B. Xu ◽  
X. F. Xu ◽  
...  
Keyword(s):  
Rural Areas ◽  
Rural Site ◽  
Ozone Formation ◽  
Prevailing Wind ◽  
Ozone Pollution ◽  
Ozone Formation Potential ◽  
Rural Sites ◽  
Urban And Rural Areas ◽  
Urban Plumes ◽  
Urban Sites

Abstract. Sea-land and mount-valley circulations are the dominant mesoscale synoptic systems affecting the Beijing area during summertime. Under the influence of these two circulations, the prevailing wind is southwesterly from afternoon to midnight, and then changes to northeasterly till forenoon. In this study, surface ozone (O3), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), nitrogen oxide (NOx) and non-methane hydrocarbons (NMHCs) were measured at four sites located along the route of prevailing wind, including two upwind urban sites (Fengtai "FT" and Baolian "BL"), an upwind suburban site (Shunyi "SY") and a downwind rural site (Shangdianzi "SDZ") during 20 June–16 September 2007. The purpose is to improve our understanding of ozone photochemistry in urban and rural areas of Beijing and the influence of urban plumes on ozone pollution in downwind rural areas. It is found that ozone pollution was synchronism in the urban and rural areas of Beijing, coinciding with the regional-scale synoptic processes. Due to the high traffic density and local emissions, the average levels of reactive gases NOx and NMHCs at the non-rural sites were much higher than those at SDZ. The level of long-lived gas CO at SDZ was comparable to, though slightly lower than, at the urban sites. We estimate the photochemical reactivity (LOH and the ozone formation potential (OFP) in the urban (BL) and rural (SDZ) areas using measured CO and NMHCs. The OH loss rate coefficient (LOH by total NMHCs at the BL and SDZ sites are estimated to be 50.7 s-1 and 15.8 s-1, respectively. While alkenes make a major contribution to the LOH, aromatics dominate OFP at both urban and rural sites. With respect to the individual species, CO has the largest ozone formation potential at the rural site, and at the urban site aromatic species are the leading contributors. While the O3 diurnal variations at the four sites are typical for polluted areas, the ozone peak values are found to lag behind one site after another along the route of prevailing wind from SW to NE. Intersection analyses of trace gases reveal that polluted air masses arriving at SDZ were more aged with both higher O3 and Ox concentrations than those at BL. The results indicate that urban plume can transport not only O3 but its precursors, the latter leading more photochemical O3 production when being mixed with background atmosphere in the downwind rural area.

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