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 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 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.

Understanding and predicting the global spread of emergent infectious diseases

2014 ◽  
Vol 22 (3) ◽  
Author(s):  
Dirk Brockmann
Keyword(s):  
Public Health ◽  
Infectious Diseases ◽  
Network Theory ◽  
Computational Models ◽  
Control Strategies ◽  
Global Scale ◽  
Disease Spread ◽  
Complex Network Theory ◽  
Global Spread ◽  
And Control

AbstractThe emergence and global spread of human infectious diseases has become one of the most serious public health threats of the 21st century. Sophisticated computer simulations have become a key tool for understanding and predicting disease spread on a global scale. Combining theoretical insights from nonlinear dynamics, stochastic processes and complex network theory these computational models are becoming increasingly important in the design of efficient mitigation and control strategies and for public health in general.

scholarly journals GASES DE NITROGÊNIO REATIVO COMO PRECURSORES DO AEROSSOL ATMOSFÉRICO: REAÇÕES DE FORMAÇÃO, PROCESSOS DE CRESCIMENTO E IMPLICAÇÕES AMBIENTAIS

Química Nova ◽  
2020 ◽  
Author(s):  
Carolina Rocha ◽  
Arnaldo Cardoso
Keyword(s):  
Atmospheric Aerosols ◽  
Atmospheric Aerosol ◽  
Radiative Forcing ◽  
Global Scale ◽  
Anthropogenic Sources ◽  
Cloud Formation ◽  
Reactive Nitrogen ◽  
Aerosol Formation ◽  
Environmental Implications ◽  
Growth Processes

REACTIVE NITROGEN GASES AS PRECURSORS OF ATMOSPHERIC AEROSOL: FORMATION REACTIONS, GROWTH PROCESSES AND ENVIRONMENTAL IMPLICATIONS. The increased emissions of reactive nitrogen gases from anthropogenic sources to the atmosphere has been pointed out as responsible for triggering a series of environmental problems at the local, regional, and global scale. Among the many consequences associated with the excess of reactive nitrogen in the environment is the increase of atmospheric aerosol formation. In this way, the present review article aims to provide an overview of the main aerosol formation reactions from the reactive nitrogen gases, their growth processes, and removal from the atmosphere. The paper also addresses the implications of increasing the atmospheric aerosol load, including effects on the planet’s radiative forcing, cloud formation and precipitation, macronutrient dispersion, visibility and human health. The possible relationship between the long-term exposure to these pollutants and COVID-19 fatality is also discussed. The need for more information related to reactive nitrogen gases and atmospheric aerosols is urgent since they act on fundamental processes on planet Earth and their quantity and composition have been abruptly changed over the last hundred years. Therefore, further investigations on this topic should be stimulated and better integrated in order to guide normative decisions and the delineation of possible solutions.

scholarly journals Ocular manifestations of emerging viral diseases

Eye ◽  
2021 ◽  
Author(s):  
Ashwin Venkatesh ◽  
Ravi Patel ◽  
Simran Goyal ◽  
Timothy Rajaratnam ◽  
Anant Sharma ◽  
...  
Keyword(s):  
Public Health ◽  
Infectious Diseases ◽  
Influenza A ◽  
Emerging Infectious Diseases ◽  
Global Scale ◽  
Viral Diseases ◽  
Valley Fever ◽  
Ocular Manifestations ◽  
Influenza A H1n1 ◽  
Emerging Viral Diseases

AbstractEmerging infectious diseases (EIDs) are an increasing threat to public health on a global scale. In recent times, the most prominent outbreaks have constituted RNA viruses, spreading via droplets (COVID-19 and Influenza A H1N1), directly between humans (Ebola and Marburg), via arthropod vectors (Dengue, Zika, West Nile, Chikungunya, Crimean Congo) and zoonotically (Lassa fever, Nipah, Rift Valley fever, Hantaviruses). However, specific approved antiviral therapies and vaccine availability are scarce, and public health measures remain critical. Patients can present with a spectrum of ocular manifestations. Emerging infectious diseases should therefore be considered in the differential diagnosis of ocular inflammatory conditions in patients inhabiting or returning from endemic territories, and more general vigilance is advisable in the context of a global pandemic. Eye specialists are in a position to facilitate swift diagnosis, improve clinical outcomes, and contribute to wider public health efforts during outbreaks. This article reviews those emerging viral diseases associated with reports of ocular manifestations and summarizes details pertinent to practicing eye specialists.

scholarly journals Cirrus clouds in a global climate model with a statistical cirrus cloud scheme

2010 ◽  
Vol 10 (12) ◽  
pp. 5449-5474 ◽  
Author(s):  
M. Wang ◽  
J. E. Penner
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Lower Troposphere ◽  
Circulation Model ◽  
Cirrus Clouds ◽  
Cloud Formation ◽  
Cirrus Cloud ◽  
Ice Crystal ◽  
Homogeneous Freezing

Abstract. A statistical cirrus cloud scheme that accounts for mesoscale temperature perturbations is implemented in a coupled aerosol and atmospheric circulation model to better represent both subgrid-scale supersaturation and cloud formation. This new scheme treats the effects of aerosol on cloud formation and ice freezing in an improved manner, and both homogeneous freezing and heterogeneous freezing are included. The scheme is able to better simulate the observed probability distribution of relative humidity compared to the scheme that was implemented in an older version of the model. Heterogeneous ice nuclei (IN) are shown to decrease the frequency of occurrence of supersaturation, and improve the comparison with observations at 192 hPa. Homogeneous freezing alone can not reproduce observed ice crystal number concentrations at low temperatures (<205 K), but the addition of heterogeneous IN improves the comparison somewhat. Increases in heterogeneous IN affect both high level cirrus clouds and low level liquid clouds. Increases in cirrus clouds lead to a more cloudy and moist lower troposphere with less precipitation, effects which we associate with the decreased convective activity. The change in the net cloud forcing is not very sensitive to the change in ice crystal concentrations, but the change in the net radiative flux at the top of the atmosphere is still large because of changes in water vapor. Changes in the magnitude of the assumed mesoscale temperature perturbations by 25% alter the ice crystal number concentrations and the net radiative fluxes by an amount that is comparable to that from a factor of 10 change in the heterogeneous IN number concentrations. Further improvements on the representation of mesoscale temperature perturbations, heterogeneous IN and the competition between homogeneous freezing and heterogeneous freezing are needed.

scholarly journals Modelling the impact of megacities on local, regional and global tropospheric ozone and the deposition of nitrogen species

2013 ◽  
Vol 13 (24) ◽  
pp. 12215-12231 ◽  
Author(s):  
Z. S. Stock ◽  
M. R. Russo ◽  
T. M. Butler ◽  
A. T. Archibald ◽  
M. G. Lawrence ◽  
...  
Keyword(s):  
Air Quality ◽  
Urban Areas ◽  
Climate Model ◽  
Surface Ozone ◽  
Global Scale ◽  
Chemical Environment ◽  
Ozone Production ◽  
The Uk ◽  
The Impact ◽  
Local Emissions

Abstract. We examine the effects of ozone precursor emissions from megacities on present-day air quality using the global chemistry–climate model UM-UKCA (UK Met Office Unified Model coupled to the UK Chemistry and Aerosols model). The sensitivity of megacity and regional ozone to local emissions, both from within the megacity and from surrounding regions, is important for determining air quality across many scales, which in turn is key for reducing human exposure to high levels of pollutants. We use two methods, perturbation and tagging, to quantify the impact of megacity emissions on global ozone. We also completely redistribute the anthropogenic emissions from megacities, to compare changes in local air quality going from centralised, densely populated megacities to decentralised, lower density urban areas. Focus is placed not only on how changes to megacity emissions affect regional and global NOx and O3, but also on changes to NOy deposition and to local chemical environments which are perturbed by the emission changes. The perturbation and tagging methods show broadly similar megacity impacts on total ozone, with the perturbation method underestimating the contribution partially because it perturbs the background chemical environment. The total redistribution of megacity emissions locally shifts the chemical environment towards more NOx-limited conditions in the megacities, which is more conducive to ozone production, and monthly mean surface ozone is found to increase up to 30% in megacities, depending on latitude and season. However, the displacement of emissions has little effect on the global annual ozone burden (0.12% change). Globally, megacity emissions are shown to contribute ~3% of total NOy deposition. The changes in O3, NOx and NOy deposition described here are useful for quantifying megacity impacts and for understanding the sensitivity of megacity regions to local emissions. The small global effects of the 100% redistribution carried out in this study suggest that the distribution of emissions on the local scale is unlikely to have large implications for chemistry–climate processes on the global scale.

Application of GIS technology in public health: successes and challenges

Parasitology ◽  
2016 ◽  
Vol 143 (4) ◽  
pp. 401-415 ◽  
Author(s):  
STEPHANIE M. FLETCHER-LARTEY ◽  
GRAZIELLA CAPRARELLI
Keyword(s):  
Public Health ◽  
Control Strategies ◽  
Health Sector ◽  
Remote Sensing Data ◽  
Environmental Data ◽  
Data Availability ◽  
Parasitic Diseases ◽  
Gis Technology ◽  
The Public ◽  
Application Of Gis

SUMMARYThe uptake and acceptance of Geographic Information Systems (GIS) technology has increased since the early 1990s and public health applications are rapidly expanding. In this paper, we summarize the common uses of GIS technology in the public health sector, emphasizing applications related to mapping and understanding of parasitic diseases. We also present some of the success stories, and discuss the challenges that still prevent a full scope application of GIS technology in the public health context. Geographical analysis has allowed researchers to interlink health, population and environmental data, thus enabling them to evaluate and quantify relationships between health-related variables and environmental risk factors at different geographical scales. The ability to access, share and utilize satellite and remote-sensing data has made possible even wider understanding of disease processes and of their links to the environment, an important consideration in the study of parasitic diseases. For example, disease prevention and control strategies resulting from investigations conducted in a GIS environment have been applied in many areas, particularly in Africa. However, there remain several challenges to a more widespread use of GIS technology, such as: limited access to GIS infrastructure, inadequate technical and analytical skills, and uneven data availability. Opportunities exist for international collaboration to address these limitations through knowledge sharing and governance.

scholarly journals Global 3D modelling of Martian CO2 clouds

2021 ◽  
Author(s):  
Christophe Mathé ◽  
Anni Määttänen ◽  
Joachim Audouard ◽  
Constantino Listowski ◽  
Ehouarn Millour ◽  
...  
Keyword(s):  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Martian Atmosphere ◽  
Cloud Formation ◽  
Polar Regions ◽  
Northern Latitudes ◽  
1D Model ◽  
Mesospheric Clouds ◽  
Microphysical Processes

&lt;p&gt;In the Martian atmosphere, carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) clouds have been revealed by numerous instruments around Mars from the beginning of the XXI century. These observed clouds can be distinguished by two kinds involving different formation processes: those formed during the winter in polar regions located in the troposphere, and those formed during the Martian year at low- and mid-northern latitudes located in the mesosphere (M&amp;#228;&amp;#228;att&amp;#228;nen et al, 2013). Microphysical processes of the formation of these clouds are still not fully understood. However, modeling studies revealed processes necessary for their formation: the requirement of waves that perturb the atmosphere leading to a temperature below the condensation of CO&lt;sub&gt;2&lt;/sub&gt; (transient planetary waves for tropospheric clouds (Kuroda et al., 20123), thermal tides (Gonzalez-Galindo et al., 2011) and gravity waves for mesospheric clouds (Spiga et al., 2012)). In the last decade, a state-of-the-art microphysical column (1D) model for CO&lt;sub&gt;2&lt;/sub&gt; clouds in a Martian atmosphere was developed at Laboratoire Atmosph&amp;#232;res, Observations Spatiales (LATMOS) (Listowski et al., 2013, 2014). We use our full microphysical model of CO&lt;sub&gt;2&lt;/sub&gt; cloud formation to investigate the occurrence of these CO&lt;sub&gt;2&lt;/sub&gt; clouds by coupling it with the Global Climate Model (GCM) of the Laboratoire de M&amp;#233;t&amp;#233;orologie Dynamique (LMD) (Forget et al., 1999). We recently activated the radiative impact of CO&lt;sub&gt;2&lt;/sub&gt; clouds in the atmosphere. Last modeling results on Martian CO&lt;sub&gt;2&lt;/sub&gt; clouds properties and their impacts on the atmosphere will be presented and be compared to observational data.&lt;/p&gt;

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