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 Radiative forcing of the desert aerosol at Ouarzazate (Morocco)

2018 ◽  
Vol 37 ◽  
pp. 03004
Author(s):  
Abdelouahid Tahiri ◽  
Mohamed Diouri
Keyword(s):  
Optical Properties ◽  
Atmospheric Aerosol ◽  
Radiative Forcing ◽  
Cloud Formation ◽  
Optical Parameters ◽  
Aerosol Radiative Forcing ◽  
Daily Average ◽  
Definition Of ◽  
Aerosol Radiative

The atmospheric aerosol contributes to the definition of the climate with direct effect, the diffusion and absorption of solar and terrestrial radiations, and indirect, the cloud formation process where aerosols behave as condensation nuclei and alter the optical properties. Satellites and ground-based networks (solar photometers) allow the terrestrial aerosol observation and the determination of impact. Desert aerosol considered among the main types of tropospheric aerosols whose optical property uncertainties are still quite important. The analysis concerns the optical parameters recorded in 2015 at Ouarzazate solar photometric station (AERONET/PHOTONS network, http://aeronet.gsfc.nasa.gov/) close to Saharan zone. The daily average aerosol optical depthτaer at 0.5μm, are relatively high in summer and less degree in spring (from 0.01 to 1.82). Daily average of the Angstrom coefficients α vary between 0.01 and 1.55. The daily average of aerosol radiative forcing at the surface range between -150W/m2 and -10 W/m2 with peaks recorded in summer, characterized locally by large loads of desert aerosol in agreement with the advections of the Southeast of Morocco. Those recorded at the Top of the atmosphere show a variation from -74 W/m2 to +24 W/m2

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 The role of low volatile organics on secondary organic aerosol formation

2014 ◽  
Vol 14 (3) ◽  
pp. 1689-1700 ◽  
Author(s):  
H. Kokkola ◽  
P. Yli-Pirilä ◽  
M. Vesterinen ◽  
H. Korhonen ◽  
H. Keskinen ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Atmospheric Aerosol ◽  
Radiative Forcing ◽  
Large Scale ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Aerosol Formation ◽  
Wall Losses ◽  
Rapid Formation ◽  
New Particles

Abstract. Large-scale atmospheric models, which typically describe secondary organic aerosol (SOA) formation based on chamber experiments, tend to systematically underestimate observed organic aerosol burdens. Since SOA constitutes a significant fraction of atmospheric aerosol, this discrepancy translates into an underestimation of SOA contribution to radiative forcing of atmospheric aerosol. Here we show that the underestimation of SOA yields can be partly explained by wall losses of SOA forming compounds during chamber experiments. We present a chamber experiment where α-pinene and ozone are injected into a Teflon chamber. When these two compounds react, we observe rapid formation and growth of new particles. Theoretical analysis of this formation and growth event indicates rapid formation of oxidized volatile organic compounds (OVOC) of very low volatility in the chamber. If these oxidized organic compounds form in the gas phase, their wall losses will have significant implications on their partitioning between the gas and particle phase. Although these OVOCs of very low volatility contribute to the growth of new particles, their mass will almost completely be depleted to the chamber walls during the experiment, while the depletion of OVOCs of higher volatilities is less efficient. According to our model simulations, the volatilities of OVOC contributing to the new particle formation event can be of the order of 10−5 μg m−3.

scholarly journals Changes in atmospheric aerosol loading retrieved from space based measurements during the past decade

2013 ◽  
Vol 13 (10) ◽  
pp. 26001-26041 ◽  
Author(s):  
J. Yoon ◽  
J. P. Burrows ◽  
M. Vountas ◽  
W. von Hoyningen-Huene ◽  
D. Y. Chang ◽  
...  
Keyword(s):  
Climate Change ◽  
Atmospheric Aerosols ◽  
Atmospheric Aerosol ◽  
Western Europe ◽  
Global Climate ◽  
Anthropogenic Sources ◽  
Radiation Balance ◽  
Industrialized Countries ◽  
Anthropogenic Pollutants ◽  
The Past

Abstract. Atmospheric aerosol, generated from natural and anthropogenic sources, plays a key role in regulating visibility, air quality, and acid deposition. It is directly linked to and impacts on human health. It also reflects and absorbs incoming solar radiation and thereby influences the climate change. The cooling by aerosols is now recognized to have partly masked the atmospheric warming from fossil fuel combustion emissions. The role and potential management of short-lived climate pollutants such as aerosol are currently a topic of much scientific and public debate. Our limited knowledge of atmospheric aerosol and its influence on the Earth's radiation balance has a significant impact on the accuracy and error of current predictions of the future global climate change. In the past decades, environmental legislation in industrialized countries has begun to limit the release of anthropogenic pollutants. In contrast, in Asia as a result of the recent rapid economic development, emissions from industry and traffic have increased dramatically. In this study, the temporal changes/trends of atmospheric aerosols, derived from the satellite instruments MODIS (on board Terra and Aqua), MISR (Terra), and SeaWiFS (OrbView-2) during the past decade, are investigated. Whilst the aerosol optical thickness, AOT, over Western Europe decreases (i.e. by up to about −40% from 2003 to 2008) and parts of North America, a statistically significant increase (about +34% in the same period) over East China is observed and attributed to both the increase in industrial output and the Asian desert dust.

scholarly journals Shortwave radiative forcing and efficiency of key aerosol types using AERONET data

2012 ◽  
Vol 12 (11) ◽  
pp. 5129-5145 ◽  
Author(s):  
O. E. García ◽  
J. P. Díaz ◽  
F. J. Expósito ◽  
A. M. Díaz ◽  
O. Dubovik ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Atmospheric Aerosols ◽  
Radiative Forcing ◽  
Mineral Dust ◽  
High Surface ◽  
Global Scale ◽  
Free Troposphere ◽  
Anthropogenic Aerosols ◽  
Radiative Balance ◽  
Absorbing Aerosols

Abstract. The shortwave radiative forcing (ΔF) and the radiative forcing efficiency (ΔFeff) of natural and anthropogenic aerosols have been analyzed using estimates of radiation both at the Top (TOA) and at the Bottom Of Atmosphere (BOA) modeled based on AERONET aerosol retrievals. Six main types of atmospheric aerosols have been compared (desert mineral dust, biomass burning, urban-industrial, continental background, oceanic and free troposphere) in similar observational conditions (i.e., for solar zenith angles between 55° and 65°) in order to compare the nearly same solar geometry. The instantaneous ΔF averages obtained vary from −122 ± 37 Wm−2 (aerosol optical depth, AOD, at 0.55 μm, 0.85 ± 0.45) at the BOA for the mixture of desert mineral dust and biomass burning aerosols in West Africa and −42 ± 22 Wm−2 (AOD = 0.9 ± 0.5) at the TOA for the pure mineral dust also in this region up to −6 ± 3 Wm−2 and −4 ± 2 Wm−2 (AOD = 0.03 ± 0.02) at the BOA and the TOA, respectively, for free troposphere conditions. This last result may be taken as reference on a global scale. Furthermore, we observe that the more absorbing aerosols are overall more efficient at the BOA in contrast to at the TOA, where they backscatter less solar energy into the space. The analysis of the radiative balance at the TOA shows that, together with the amount of aerosols and their absorptive capacity, it is essential to consider the surface albedo of the region on which they are. Thus, we document that in regions with high surface reflectivity (deserts and snow conditions) atmospheric aerosols lead to a warming of the Earth-atmosphere system.

PEEX Integrated Multi-scales and -Process Modelling for Environmental Applications

2020 ◽  
Author(s):  
Alexander Mahura ◽  
Alexander Baklanov ◽  
Tuukka Petäjä ◽  
Roman Nuterman ◽  
Serguei Ivanov ◽  
...  
Keyword(s):  
Data Assimilation ◽  
Radiative Forcing ◽  
High Performance ◽  
Regional Scale ◽  
Added Value ◽  
Anthropogenic Sources ◽  
Cloud Formation ◽  
Limited Area ◽  
Multi Scale

<p>The Pan-Eurasian EXperiment (PEEX; www.atm.helsinki.fi/peex) programme is a long-term programme. One of the PEEX Research Infrastructure’s components is the PEEX-Modelling-Platform (PEEX-MP; www.atm.helsinki.fi/peex/index.php/modelling-platform). PEEX-MP includes more than 30 different models running at different scales, resolutions, geographical domains, resolving different physical-chemical-biological processes, etc. and used as research tools providing insights and valuable information/ output for different level assessments for environment and population. These models cover main components - atmosphere, hydrosphere, pedosphere and biosphere. The seamless coupling multi-scale and -processes modelling concept developed is important and advanced step towards realization of the PEEX research agenda presented in the PEEX Science Plan (www.atm.helsinki.fi/peex/images/PEEX_Science_Plan.pdf). Accessibility to infrastructure with High Performance Computing is important for such modelling.</p><p>In particular, the Enviro-HIRLAM (Environment – HIgh Resolution Limited Area Model) & HARMONIE (The HIRLAM-ALADIN Research for Meso-scale Operational NWP In Europe) models can be applied for multi-scale and –processes studies on interactions and feedbacks of meteorology vs aerosols/chemistry; aerosols vs. cloud formation and radiative forcing; boundary layer parameterizations; urbanization processes impact on changes in urban weather and climate; assessments for human and environment; improving prediction of extreme weather/ pollution events; etc. All these can be studied at different spatial (urban-subregional-regional) and temporal scales. In addition, added value to analysis is obtained through integration of modelling results into GIS environment for further risk/vulnerability/consequences/etc. studies.</p><p>As part of the Enviro-PEEX project (www.atm.helsinki.fi/peex/index.php/enviro), the models were used to study aerosols feedbacks and interactions in Arctic-boreal domain at regional scale & effects of radar data assimilation at mesoscale resolution, respectively.</p><p>Enviro-HIRLAM model was run in a long-term mode at 15-5 km resolutions for reference and aerosols effects (direct, indirect, combined included) with ECMWF boundary conditions and anthropogenic/ biogenic/ natural emissions pre-processed. Analysis of differences between model runs for basic statistics (avg, med, max, min, std) showed less pronounced variations of concentrations for average in Arctic regions vs other regions, and more pronounced for maximum concentration in Russian Siberia and Ural. Monthly averaged sulphur dioxide was larger over mid-latitudes (influence of anthropogenic sources) with maximum due to long-range atmospheric transport. For particular matter, it is lower in Arctic compared with mid-latitudes, but their composition is dominated by sea salt aerosols.</p><p>HARMONIE model was tested with pre-processing (optimising inner parameters) and data assimilation of radar reflectivity, which minimize a representative error (associated with discrepancy between resolutions in informational sources). The method showed improvement in prediction of precipitation rain rates and spatial pattern within radars’ location areas and better reproduction of mesoscale belts and cell patterns of few-to-ten size in precipitation fields. Compatibility between model resolution and smoothed radar observation density was achieved by “cube-smoothing” approach. This ensures equivalent presentation of precipitation (reflectivity) structures in both model and observation in a sense of equally preserving the scales of precipitation patterns.</p><p>Moreover, for selected PEEX-MP models, used by UHEL-INAR, such Enviro-HIRLAM, EC-Earth, MALTE-Box a series of science education oriented trainings/schools is organized in April & August 2020 (ums.rshu.ru & worldslargerivers.boku.ac.at/wlr/index.php/ysss.html) which are part of the PEEX Educational Platform activities as well.</p>

scholarly journals Impact of a hydrophobic ion on the early stage of atmospheric aerosol formation

2019 ◽  
Vol 116 (45) ◽  
pp. 22540-22544 ◽  
Author(s):  
Linda Feketeová ◽  
Paul Bertier ◽  
Thibaud Salbaing ◽  
Toshiyuki Azuma ◽  
Florent Calvo ◽  
...  
Keyword(s):  
Atmospheric Aerosol ◽  
Water Cluster ◽  
Water Clusters ◽  
Early Stage ◽  
Cloud Formation ◽  
Water Molecules ◽  
Cluster Growth ◽  
Aerosol Formation ◽  
Early Stages ◽  
Pyridinium Ion

Atmospheric aerosols are one of the major factors affecting planetary climate, and the addition of anthropogenic molecules into the atmosphere is known to strongly affect cloud formation. The broad variety of compounds present in such dilute media and their specific underlying thermalization processes at the nanoscale make a complete quantitative description of atmospheric aerosol formation certainly challenging. In particular, it requires fundamental knowledge about the role of impurities in water cluster growth, a crucial step in the early stage of aerosol and cloud formation. Here, we show how a hydrophobic pyridinium ion within a water cluster drastically changes the thermalization properties, which will in turn change the corresponding propensity for water cluster growth. The combination of velocity map imaging with a recently developed mass spectrometry technique allows the direct measurement of the velocity distribution of the water molecules evaporated from excited clusters. In contrast to previous results on pure water clusters, the low-velocity part of the distributions for pyridinium-doped water clusters is composed of 2 distinct Maxwell–Boltzmann distributions, indicating out-of-equilibrium evaporation. More generally, the evaporation of water molecules from excited clusters is found to be much slower when the cluster is doped with a pyridinium ion. Therefore, the presence of a contaminant molecule in the nascent cluster changes the energy storage and disposal in the early stages of gas-to-particle conversion, thereby leading to an increased rate of formation of water clusters and consequently facilitating homogeneous nucleation at the early stages of atmospheric aerosol formation.

scholarly journals The influence of megacities on global atmospheric chemistry: a modelling study

2009 ◽  
Vol 6 (3) ◽  
pp. 219 ◽  
Author(s):  
Timothy M. Butler ◽  
Mark G. Lawrence
Keyword(s):  
Atmospheric Chemistry ◽  
Urban Areas ◽  
Radiative Forcing ◽  
Transport Model ◽  
Spatial Scales ◽  
Global Scale ◽  
Reactive Nitrogen ◽  
Grid Cells ◽  
Chemical Transport Model ◽  
Future Scenario

Environmental context. Over half of the population of the world now live in urban areas, and the number of so-called ‘megacities’, with populations of ~10 million or more, is growing at a tremendous rate. We show how these patterns of urbanisation have the potential to influence the atmospheric chemical environment on a global scale, particularly through the effects of emissions from megacities on the reactive nitrogen cycle. With the growing worldwide interest in the study of the effects of megacities at all spatial scales, such as current European Union projects MEGAPOLI and CityZen, our study represents the first of many future studies that examine the effects of megacities on atmospheric chemistry on the global scale. Abstract. We present the first study of the effects of megacities on global atmospheric chemistry using a global three-dimensional chemical transport model. The effects on air quality, radiative forcing and atmospheric oxidation capacity are disproportionately smaller than the proportion of anthropogenic emissions due to megacities. Disproportionately large effects of megacities are modelled for reactive nitrogen compounds, in particular PAN (peroxy acetyl nitrate), which has increased in abundance globally by 9% due to megacities under year 2000 conditions, with 23% of the Earth experiencing an increase of 10% or more. These influences decrease under two very different future emission scenarios. Under a low-emission future scenario, the influence of megacities is generally reduced, and under a high-emission future scenario, although the local influence of megacities is increased, the geographical extent of the influence becomes smaller. In our model, the individual grid cells that contain megacities respond to the megacity emissions differently depending on their latitude. Tropical megacity grid cells generally show increased ozone year-round, while northern extratropical megacities generally show reduced ozone year-round. Better parameterisation of the sub-grid effects of megacities is an important issue for future work.

scholarly journals Exploring DMS oxidation and implications for global aerosol radiative forcing

2021 ◽  
Author(s):  
Ka Ming Fung ◽  
Colette L. Heald ◽  
Jesse H. Kroll ◽  
Siyuan Wang ◽  
Duseong S. Jo ◽  
...  
Keyword(s):  
Gas Phase ◽  
Radiative Forcing ◽  
Dimethyl Sulfide ◽  
Methanesulfonic Acid ◽  
Atmospheric Model ◽  
Cloud Formation ◽  
Aerosol Formation ◽  
Gas Phase Chemistry ◽  
Dms Oxidation ◽  
Phase Chemistry

Abstract. Aerosol indirect radiative forcing (IRF), which characterizes how aerosols alter cloud formation and properties, is very sensitive to the preindustrial (PI) aerosol burden. Dimethyl sulfide (DMS), emitted from the ocean, is a dominant natural precursor of non-sea-salt sulfate in the PI and pristine present-day (PD) atmospheres. Here we revisit the atmospheric oxidation chemistry of DMS, particularly under pristine conditions, and its impact on aerosol IRF. Based on previous laboratory studies, we expand the simplified DMS oxidation scheme used in the Community Atmospheric Model version 6 with chemistry (CAM6-chem) to capture the OH-addition pathway as well as the H-abstraction pathway and the associated isomerization branch. These additional oxidation channels of DMS produce several stable intermediate compounds, e.g., methanesulfonic acid (MSA) and hydroperoxymethyl thioformate (HPMTF), delay the formation of sulfate, and hence, alter the spatial distribution of sulfate aerosol and radiative impacts. The expanded scheme improves the agreement between modeled and observed concentrations of DMS, MSA, HPMTF, and sulfate over most marine regions based on the NASA Atmospheric Tomography (ATom), the Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA), and the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-REx) measurements. We find that the global HPMTF burden, as well as the burden of sulfate produced from DMS oxidation are relatively insensitive to the assumed isomerization rate, but the burden of HPMTF is very sensitive to a potential additional cloud loss. We find that global sulfate burden under PI and PD emissions increase to 412 Gg-S (+29 %) and 582 Gg-S (+8.8 %), respectively, compared to the standard simplified DMS oxidation scheme. The resulting annual mean global PD direct radiative effect of DMS-derived sulfate alone is −0.11  W m−2. The enhanced PI sulfate produced via the gas-phase chemistry updates alone dampens the aerosol IRF as anticipated (−2.2 W m−2 in standard versus −1.7 W m−2 with updated gas-phase chemistry). However, high clouds in the tropics and low clouds in the Southern Ocean appear particularly sensitive to the additional aqueous-phase pathways, counteracting this change (−2.3 W m−2). This study confirms the sensitivity of aerosol IRF to the PI aerosol loading, as well as the need to better understand the processes controlling aerosol formation in the PI atmosphere and the cloud response to these changes.

scholarly journals Shortwave radiative forcing and efficiency of key aerosol types using AERONET data

2011 ◽  
Vol 11 (12) ◽  
pp. 32647-32684 ◽  
Author(s):  
O. E. García ◽  
J. P. Díaz ◽  
F. J. Expósito ◽  
A. M. Díaz ◽  
O. Dubovik ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Atmospheric Aerosols ◽  
Radiative Forcing ◽  
Mineral Dust ◽  
High Surface ◽  
Central Africa ◽  
Global Scale ◽  
Free Troposphere ◽  
Anthropogenic Aerosols ◽  
Radiative Balance

Abstract. The shortwave radiative forcing (ΔF) and the radiative forcing efficiency (ΔFeff) of natural and anthropogenic aerosols have been analyzed using estimates of radiation both at the top (TOA) and at the bottom of atmosphere (BOA) modeled based on AERONET aerosol retrievals. In this study we have considered six main types of atmospheric aerosols: desert mineral dust, biomass burning, urban-industrial, continental background, oceanic and free troposphere. The ΔF averages obtained vary from −148 ± 44 Wm−2 (aerosol optical depth, AOD, at 0.55 μm, 0.85 ± 0.45) at the BOA for the mixture of desert mineral dust and biomass burning aerosols in Central Africa and −42 ± 22 Wm−2 (AOD = 0.86 ± 0.51) at the TOA for the pure mineral dust also in this region up to −6 ± 3 Wm−2 and −4 ± 2 Wm−2 (AOD = 0.03 ± 0.02) at the BOA and the TOA, respectively, for free troposphere conditions. This last result may be taken as reference on a global scale. Furthermore, we observe that the more absorbing aerosols are overall more efficient at the BOA in contrast to at the TOA, where they backscatter less solar energy into the space. The analysis of the radiative balance at the TOA shows that, together with the amount of aerosols and their absorptive capacity, it is essential to consider the surface albedo of the region on which they are. Thus, we document that in regions with high surface reflectivity (deserts and snow conditions) atmospheric aerosols lead to a warming of the Earth-atmosphere system, contributing to the greenhouse gas effect.

Sign in / Sign up

Export Citation Format

Share Document