scholarly journals How alkaline compounds control atmospheric aerosol particle acidity

2021 ◽  
Vol 21 (19) ◽  
pp. 14983-15001
Author(s):  
Vlassis A. Karydis ◽  
Alexandra P. Tsimpidi ◽  
Andrea Pozzer ◽  
Jos Lelieveld
Keyword(s):  
Public Health ◽  
Aerosol Particle ◽  
Atmospheric Chemistry ◽  
Climate Model ◽  
Control Strategies ◽  
Atmospheric Particulate Matter ◽  
Cloud Formation ◽  
Mass Composition ◽  
The Past ◽  
Aerosol Hygroscopicity

Abstract. The acidity of atmospheric particulate matter regulates its mass, composition, and toxicity and has important consequences for public health, ecosystems and climate. Despite these broad impacts, the global distribution and evolution of aerosol particle acidity are unknown. We used the comprehensive atmospheric multiphase chemistry–climate model EMAC (ECHAM5/MESSy Atmospheric Chemistry) to investigate the main factors that control aerosol particle acidity and uncovered remarkable variability and unexpected trends during the past 50 years in different parts of the world. Aerosol particle acidity decreased strongly over Europe and North America during the past decades while at the same time it increased over Asia. Our simulations revealed that these particle acidity trends are strongly related to changes in the phase partitioning of nitric acid, production of sulfate in aqueous aerosols, and the aerosol hygroscopicity. It is remarkable that the aerosol hygroscopicity (κ) has increased in many regions following the particle pH. Overall, we find that alkaline compounds, notably ammonium and to a lesser extent crustal cations, regulate the particle pH on a global scale. Given the importance of aerosol particles for the atmospheric energy budget, cloud formation, pollutant deposition, and public health, alkaline species hold the key to control strategies for air quality and climate change.

scholarly journals How alkaline compounds control atmospheric aerosol acidity

2020 ◽  
Author(s):  
Vlassis A. Karydis ◽  
Alexandra P. Tsimpidi ◽  
Andrea Pozzer ◽  
Jos Lelieveld
Keyword(s):  
Public Health ◽  
Atmospheric Aerosols ◽  
Climate Model ◽  
Control Strategies ◽  
Global Scale ◽  
Cloud Formation ◽  
Mass Composition ◽  
Aerosol Acidity ◽  
Pollutant Deposition ◽  
Particulate Mass

Abstract. The acidity of atmospheric aerosols regulates the particulate mass, composition and toxicity, and has important consequences for public health, ecosystems and climate. Despite these broad impacts, the global distribution and evolution of aerosol acidity are unknown. We used the particular, comprehensive atmospheric multiphase chemistry – climate model EMAC to investigate the main factors that control aerosol acidity, and uncovered remarkable variability and unexpected trends during the past 50 years in different parts of the world. We find that alkaline compounds, notably ammonium, and to a lesser extent crustal cations, buffer the aerosol pH on a global scale. Given the importance of aerosols for the atmospheric energy budget, cloud formation, pollutant deposition and public health, alkaline species hold the key to control strategies for air quality and climate change.

scholarly journals A simplified empirical method for determination of aerosol hygroscopicity and composition

2010 ◽  
Vol 10 (10) ◽  
pp. 23627-23656
Author(s):  
C. H. Chan ◽  
A. Y. S. Cheng ◽  
A. Viseu
Keyword(s):  
Atmospheric Aerosols ◽  
Climate Model ◽  
Empirical Method ◽  
Radiation Budget ◽  
Cloud Formation ◽  
Monthly Variation ◽  
Aerosol Composition ◽  
Remote System ◽  
Aerosol Hygroscopicity

Abstract. Atmospheric aerosols have substantial influence on the Earth's radiation budget, visibility, cloud formation and precipitation. The aerosol hygroscopicity and the composition of aerosols are of vital importance for solar radiation budget calculation, cloud formation mechanism, and measurement of aerosol spatiotemporal distribution through remote sensing, such as Lidar, MODIS and sun/star photometer. In this paper, hourly averaged records of humidity, visibility and aerosol concentration, conducted in Macao, P.R.C. from 1 February 2006 to 31 December 2008 (LT), are used to estimate aerosol hygroscopicity and composition with a simplified empirical method. The result of monthly variation of aerosol hygroscopicity indicates the important role of aerosol composition on optical properties, which is in agreement with the previous study. This aerosol composition pattern is also consistent with the Asiatic Monsoon pattern and vicinity, such as Hong Kong. The monthly variation of aerosol hygroscopicity and composition also shows the necessity to consider such a factor for the aerosols monitoring by remote system and aerosols forcing simulated by climate model.

scholarly journals Global distribution of the effective aerosol hygroscopicity parameter for CCN activation

2010 ◽  
Vol 10 (3) ◽  
pp. 6301-6339 ◽  
Author(s):  
K. J. Pringle ◽  
H. Tost ◽  
A. Pozzer ◽  
U. Pöschl ◽  
J. Lelieveld
Keyword(s):  
Boundary Layer ◽  
Standard Deviation ◽  
Planetary Boundary Layer ◽  
Atmospheric Chemistry ◽  
Regional Distribution ◽  
Cloud Condensation Nucleus ◽  
Cloud Formation ◽  
Sea Spray ◽  
Mean Values ◽  
Aerosol Hygroscopicity

Abstract. In this study we use the ECHAM/MESSy Atmospheric Chemistry (EMAC) model to simulate global fields of the effective hygroscopicity parameter κ which approximately describes the influence of chemical composition on the cloud condensation nucleus (CCN) activity of aerosol particles. The obtained global mean values of κ at the Earth's surface are 0.27±0.21 for continental and 0.72±0.24 for marine regions (arithmetic mean ± standard deviation). The mean κ values are in good agreement with previous estimates based on observational data, but the model standard deviation for continental regions is higher. Over the continents, the regional distribution appears fairly uniform, with κ values mostly in the range of 0.1–0.4. Lower values over large arid regions and regions of high organic loading lead to reduced continental average values for Africa and South America (0.15–0.17) compared to the other continents (0.21–0.36). Marine regions show greater variability with κ values ranging from 0.9–1.0 in remote regions to 0.4–0.6 in continental outflow regions where the highly hygroscopic sea spray aerosol mixes with less hygroscopic continental aerosol. Marine κ values as low as 0.2–0.3 are simulated in the outflow from the Sahara desert. At the top of the planetary boundary layer the κ values can deviate substantially from those at the surface (up to 30%) – especially in marine and coastal regions. In moving from the surface to the height of the planetary boundary layer, the global average marine κ value reduces by 20%. Thus, surface observations may not always be representative for the altitudes where cloud formation mostly occurs. In a pre-industrial model scenario, the κ values tend to be higher over marine regions and lower over the continents, because the anthropogenic particulate matter is on average less hygroscopic than sea-spray but more hygroscopic than the natural continental background aerosol (dust and organic matter). The influence of industrialisation on aerosol hygroscopicity appears to be less pronounced than the influence on the atmospheric aerosol burden. However, in regions influenced by desert dust the particle hygroscopicity has increased strongly as the mixing of air pollutants with mineral particles typically enhances the Kappa values by a factor of 2–3.

scholarly journals Comparison of ECHAM5/MESSy Atmospheric Chemistry (EMAC) Simulations of the Arctic winter 2009/2010 and 2010/2011 with Envisat/MIPAS and Aura/MLS Observations

2018 ◽  
Author(s):  
Farahnaz Khosrawi ◽  
Oliver Kirner ◽  
Gabriele Stiller ◽  
Michael Höpfner ◽  
Michelle L. Santee ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Climate Model ◽  
Michelson Interferometer ◽  
Volume Density ◽  
Cloud Formation ◽  
The Arctic ◽  
Cold Temperatures ◽  
Vertical Extension ◽  
Polar Stratospheric Cloud ◽  
Realistic Representation

Abstract. We present model simulations with the atmospheric chemistry-climate model ECHAM5/MESSy Atmospheric Chemistry (EMAC) nudged toward European Center for Medium-Range Weather Forecasts (ECMWF) reanalyses for the Arctic winter 2009/2010 and 2010/2011. This study is the first to perform an extensive assessment of the performance of the EMAC model for Arctic winters; previous studies have only made limited evaluations of EMAC simulations for the Arctic. We have chosen the two extreme Arctic winters 2009/2010 and 2010/2011 to evaluate the formation of polar stratospheric clouds (PSCs) and the representation of the chemistry and dynamics of the polar winter stratosphere in EMAC. The EMAC simulations are compared to observations by the Michelson Interferometer for Passive Atmospheric Soundings (Envisat/MIPAS) and the observations from the Aura Microwave Limb Sounder (Aura/MLS). The Arctic winter 2010/2011 was one of the coldest winters on record, leading to the strongest depletion of ozone measured in the Arctic. The Arctic winter 2009/2010 was, from the climatological perspective, one of the warmest winters on record. However, it was distinguished by an exceptionally cold stratosphere (colder than the climatological mean). Cold temperatures prevailed from mid December 2009 to mid January 2010, leading to prolonged PSC formation and existence. Significant denitrification, the removal of HNO3 from the stratosphere by sedimentation of HNO3 containing polar stratospheric cloud particles, occurred. In our comparison, we focus on polar stratospheric cloud formation and denitrification. The comparisons between EMAC simulations and satellite observations show that model and measurements compare well for these two Arctic winters (differences for HNO3 generally within ±20 %) and thus that EMAC nudged toward ECMWF reanalyses is capable of giving a realistic representation of the evolution of PSCs and the associated sequestration of gas-phase HNO3 in the polar winter stratosphere. However, simulated PSC volume densities are several orders of magnitude smaller than the ones derived from Envisat/MIPAS observations. Further, PSCs in EMAC are not simulated as high up as they are observed. This underestimation of PSC volume density and vertical extension of the PSCs results in an underestimation of the vertical redistribution of HNO3 due to denitrification/re-nitrification.

scholarly journals Radiative and dynamical contributions to past and future Arctic stratospheric temperature trends

2014 ◽  
Vol 14 (3) ◽  
pp. 1679-1688 ◽  
Author(s):  
P. Bohlinger ◽  
B.-M. Sinnhuber ◽  
R. Ruhnke ◽  
O. Kirner
Keyword(s):  
Atmospheric Chemistry ◽  
Planetary Wave ◽  
Climate Model ◽  
Stratospheric Ozone ◽  
Wave Activity ◽  
The Arctic ◽  
Radiosonde Data ◽  
Data Set ◽  
The Past ◽  
Stratospheric Temperature

Abstract. Arctic stratospheric ozone depletion is closely linked to the occurrence of low stratospheric temperatures. There are indications that cold winters in the Arctic stratosphere have been getting colder, raising the question if and to what extent a cooling of the Arctic stratosphere may continue into the future. We use meteorological reanalyses from the European Centre for Medium Range Weather Forecasts (ECMWF) ERA-Interim and NASA's Modern-Era Retrospective-Analysis for Research and Applications (MERRA) for the past 32 yr together with calculations of the chemistry-climate model (CCM) ECHAM/MESSy Atmospheric Chemistry (EMAC) and models from the Chemistry-Climate Model Validation (CCMVal) project to infer radiative and dynamical contributions to long-term Arctic stratospheric temperature changes. For the past three decades the reanalyses show a warming trend in winter and cooling trend in spring and summer, which agree well with trends from the Radiosonde Innovation Composite Homogenization (RICH) adjusted radiosonde data set. Changes in winter and spring are caused by a corresponding change of planetary wave activity with increases in winter and decreases in spring. During winter the increase of planetary wave activity is counteracted by a residual radiatively induced cooling. Stratospheric radiatively induced cooling is detected throughout all seasons, being highly significant in spring and summer. This means that for a given dynamical situation, according to ERA-Interim the annual mean temperature of the Arctic lower stratosphere has been cooling by −0.41 ± 0.11 K decade−1 at 50 hPa over the past 32 yr. Calculations with state-of-the-art models from CCMVal and the EMAC model qualitatively reproduce the radiatively induced cooling for the past decades, but underestimate the amount of radiatively induced cooling deduced from reanalyses. There are indications that this discrepancy could be partly related to a possible underestimation of past Arctic ozone trends in the models. The models project a continued cooling of the Arctic stratosphere over the coming decades (2001–2049) that is for the annual mean about 40% less than the modeled cooling for the past, due to the reduction of ozone depleting substances and the resulting ozone recovery. This projected cooling in turn could offset between 15 and 40% of the Arctic ozone recovery.

LGBTQ Intimate Partner Violence

2017 ◽  
Author(s):  
Adam M. Messinger
Keyword(s):  
Public Health ◽  
Intimate Partner Violence ◽  
Partner Violence ◽  
Intimate Partner ◽  
Sexual Relationships ◽  
Evidence Based ◽  
Policy Practice ◽  
The Past ◽  
Victim Services ◽  
Public Health Threat

Many nations today recognize intimate partner violence (IPV) in romantic-sexual relationships as a major public health threat, yet not all victims are treated equally. Contrary to myths, lesbian, gay, bisexual, trans*, and queer (LGBTQ) people are more likely to experience IPV than heterosexual-cisgender people. Unfortunately, LGBTQ victims face major barriers to reaching safety in a world that too often stigmatizes their identities and overlooks their relationships when forming victim services and policies. Offering a roadmap forward, LGBTQ Intimate Partner Violence: Lessons for Policy, Practice, and Research is the first book to synthesize nearly all existing research from the past forty years on this pressing issue. At once highly organized and engaging, it provides evidence-based tips for academic and nonacademic audiences alike.

scholarly journals Phylogenetic Complexity of Morphologically Identified Anopheles squamosus in Southern Zambia

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 146
Author(s):  
Jordan Hoffman ◽  
Ilinca Ciubotariu ◽  
Limonty Simubali ◽  
Twig Mudenda ◽  
William Moss ◽  
...  
Keyword(s):  
Phylogenetic Relationships ◽  
Catchment Area ◽  
Control Strategies ◽  
Light Trap ◽  
Current Control ◽  
Control Measures ◽  
Morphological Identification ◽  
The Past ◽  
Blood Meal Source ◽  
Residual Malaria Transmission

Despite dramatic reductions in malaria cases in the catchment area of Macha Hospital, Choma District, Southern Province in Zambia, prevalence has remained near 1–2% by RDT for the past several years. To investigate residual malaria transmission in the area, this study focuses on the relative abundance, foraging behavior, and phylogenetic relationships of Anopheles squamosus specimens. In 2011, higher than expected rates of anthropophily were observed among “zoophilic” An. squamosus, a species that had sporadically been found to contain Plasmodium falciparum sporozoites. The importance of An. squamosus in the region was reaffirmed in 2016 when P. falciparum sporozoites were detected in numerous An. squamosus specimens. This study analyzed Centers for Disease Control (CDC) light trap collections of adult mosquitoes from two collection schemes: one performed as part of a reactive-test-and-treat program and the second performed along a geographical transect. Morphological identification, molecular verification of anopheline species, and blood meal source were determined on individual samples. Data from these collections supported earlier studies demonstrating An. squamosus to be primarily exophagic and zoophilic, allowing them to evade current control measures. The phylogenetic relationships generated from the specimens in this study illustrate the existence of well supported clade structure among An. squamosus specimens, which further emphasizes the importance of molecular identification of vectors. The primarily exophagic behavior of An. squamosus in these collections also highlights that indoor vector control strategies will not be sufficient for elimination of malaria in southern Zambia.

Preventive aspect of ayurveda and yoga towards newly emerging disease COVID-19

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ranjeet S. Sawant ◽  
Bharat D. Zinjurke ◽  
Sandeep V. Binorkar
Keyword(s):  
Public Health ◽  
Severe Acute Respiratory Syndrome ◽  
Medical Care ◽  
Supportive Therapy ◽  
Prophylactic Therapy ◽  
Current Line ◽  
Therapeutic Aspect ◽  
The Past

Abstract The ongoing coronavirus pandemic is caused by severe acute respiratory syndrome coronavirus 2 (SARS CoV 2) and unique in various facets. The earlier experience from the past severe acute respiratory syndrome (SARS) epidemics seem to be insufficient and there is need for better strategies in public health and medical care. Ayurved & Yog are well known for their preventive and therapeutic aspect, but not getting utilized properly for prevention of Covid 19 crisis which may also be helpful as supportive therapy along with current line of management. This paper is aimed at unrevealing the role of Ayurved and Yoga guidelines established by Department of AYUSH for prevention from SARS-CoV-2 by providing help to improving the quality of supportive/prophylactic therapy in relation with their immunity.

scholarly journals Trends in breastfeeding practices and mothers’ experience in the French NutriNet-Santé cohort

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Frédéric Courtois ◽  
Sandrine Péneau ◽  
Benoît Salanave ◽  
Valentina A. Andreeva ◽  
Marie Françoise Roland-Cachera ◽  
...  
Keyword(s):  
Public Health ◽  
Census Data ◽  
Breastfeeding Duration ◽  
Breastfeeding Initiation ◽  
Breastfeeding Support ◽  
The Public ◽  
The Past ◽  
Breastfeeding Practices ◽  
Breastfeeding Education ◽  
Breastfeeding Cessation

Abstract Background France has one of the lowest rates in the world regarding breastfeeding initiation and duration. Few studies have explored breastfeeding practices in France since the middle of the twentieth century, or following from initiation to cessation. The purpose of our study was to determine trends in breastfeeding over the past decades regarding public health recommendations, and to examine mothers’ perceptions about factors known to have an impact on breastfeeding support and cessation. Methods From the NutriNet-Santé cohort, 29,953 parous women (launched in 2009 to study relation between nutrition and health), were included in the present study. Using web-questionnaires, they were asked retrospectively if they had breastfed their youngest child or not, and if so, the duration of exclusive and total breastfeeding. For those who had breastfed, we investigated their perceptions about support at initiation and during the entire breastfeeding period and reasons for breastfeeding cessation. We also asked those who did not breastfeed about their perceptions and reasons for infant formula feeding their youngest child. Analyses were weighted according to the French census data. Results In the NutriNet-Santé cohort, 67.3% of mothers breastfed their youngest child. The proportion of breastfed children increased over the past few decades, from 55.0% (95% CI 54.3, 55.6) in the 1970s to 82.9% (82.4, 83.4) in the 2010s. Total and exclusive breastfeeding duration went from 3.3 months and 2.4 months respectively in the 1970s to 5.9 months and 3.2 months respectively in the 2010s. Most mothers felt supported at initiation and during the breastfeeding period. A reported desire to have breastfed longer than two months was 59.5%. Mothers who did not breastfeed did it by choice (64.3%). They did not feel guilty (78.2%) and did not perceive a problem not to breastfeed (58.8%), but almost half of them would have liked to have breastfed (45.9%). Conclusion Breastfeeding duration has increased in the past decades but did not reach the public health recommendations threshold. Targets other than mothers have to be considered for breastfeeding education, like the partner and her environment, to increase breastfeeding practices. Trial registration The study was registered at ClinicalTrials.gov (NCT03335644).

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