Variability of trends observed in Atmospheric Aerosol optical properties over Pune, India

2020 ◽  
Author(s):  
Sudeep Das ◽  
Govindan Pandithurai
Keyword(s):  
Optical Properties ◽  
Air Quality ◽  
Role Model ◽  
Anthropogenic Activities ◽  
Sea Salt ◽  
Negative Slope ◽  
Average Height ◽  
Aerosol Optical Properties ◽  
The City ◽  
Monthly Variations

<p>Long term trends of various aerosol optical properties are observed over the city of Pune, the ninth most populated city in India using ground and satellite based instruments such as AERONET, MODIS (Aqua and Terra), MISR, CALIOP and reanalysis tool MERRA. Annually, the Aerosol Optical Depth is observed to be increasing over all the types of instruments (2004-17) with values of 0.01 to 0.006 yr<sup>-1</sup>, whereas the Angstrom exponent has a negative slope (AERONET) which suggests that the fine aerosols are decreasing. Single scattering albedo (SSA) is also increasing (0.00657 yr<sup>-1</sup>), which means the emission of smaller darker particles like soot has decreased over the years. MISR shows that the Absorbing AOD trend is decreasing in the overall study period (-0.0001237 yr<sup>-1</sup>). All these annual trends are related to anthropogenic activities and show differing trends before and after 2008, the year when various pollution counter measures were introduced mainly in Pune and also in various nearby areas. After 2008, the AOD increasing slope reduces, and the AAOD reverses the trend from positive to a negative slope. The average height till various kinds of aerosols reach and their vertical profile is studied using CALIOP data. Monthly variations of AOD and their vertical distribution also observed and discussed. Aerosol characterization is done using the MERRA tool into dust, sea salt, sulfates, elementary carbon, and organic carbon. Their monthly variations are explained by source characterizations using the HySplit model. In summer, air from the Arabian sea brings in dust and sea salt into the city and in winter, aerosols come from central India dominantly as carbon and sulfates changing the air quality over there. This study lays its stress on the fact that even though aerosols cover over a city is mostly non-local, anthropogenic activities of that area do play a significant role and here the city of Pune is a role model to show how measures can be taken to improve air quality over any urban area.</p>

scholarly journals Measurements of Local Sources of Particulates with a Portable Monitor along the Coast of an Insular City

2020 ◽  
Vol 13 (1) ◽  
pp. 261
Author(s):  
Christos Petsas ◽  
Marinos Stylianou ◽  
Antonis Zorpas ◽  
Agapios Agapiou
Keyword(s):  
Air Quality ◽  
Significant Contribution ◽  
Anthropogenic Activities ◽  
Portable Monitor ◽  
Traffic Jam ◽  
Modern Cities ◽  
Anthropogenic Processes ◽  
The City ◽  
Coastal Front

The air quality of modern cities is considered an important factor for the quality of life of humans and therefore is being safeguarded by various international organizations, concentrating on the mass concentration of particulate matter (PM) with an aerodynamic diameter less than 10, 2.5 and 1 μm. However, the different physical and anthropogenic processes and activities within the city contribute to the rise of fine (<1 μm) and coarse (>1 μm) particles, directly impacting human health and the environment. In order to monitor certain natural and anthropogenic events, suspecting their significant contribution to PM concentrations, seven different events taking place on the coastal front of the city of Limassol (Cyprus) were on-site monitored using a portable PM instrument; these included both natural (e.g., dust event) and anthropogenic (e.g., cement factory, meat festival, tall building construction, tire factory, traffic jam, dust road) emissions taking place in spring and summer periods. The violations of the limits that were noticed were attributed mainly to the various anthropogenic activities taking place on-site, revealing once more the need for further research and continuous monitoring of air quality.

Interactive Aerosol Feedbacks on Photolysis Rates in the GEM-MACH Air Quality Model for an Athabasca Oil-Sands Modelling Study

2020 ◽  
Author(s):  
Mahtab Majdzadeh ◽  
Craig Stroud ◽  
Ayodeji Akingunola ◽  
Paul Makar ◽  
Christopher Sioris ◽  
...  
Keyword(s):  
Optical Properties ◽  
Air Quality ◽  
Radiative Transfer ◽  
Forest Fire ◽  
Lookup Table ◽  
Aerosol Optical Properties ◽  
Extinction Efficiency ◽  
Scattering Cross ◽  
Photolysis Rates ◽  
On Line

&lt;p&gt;The radiative transfer module of an on-line chemical transport models requires input data from aerosol extinction efficiency, single scatter albedo and asymmetry factor, in order to predict the radiative state of the atmosphere. These aerosol optical properties (aerosol optical depth, AOD), may be integrated vertically for comparison to satellite observations. These optical effects may also influence the shorter wavelengths associated with atmospheric gas photolysis, influencing atmospheric reactivity. These processes may be harmonized in an on-line reaction transport model, such as Environment and Climate Change Canada&amp;#8217;s GEM-MACH (GEM: Global Environmental Multi-scale &amp;#8211; MACH: Modelling Air quality and Chemistry). Previous photolysis routine in the radiative transfer module, MESSY-JVAL (Modular Earth Sub-Model System), in GEM-MACH, made use of a climatology of aerosol optical properties, and the previous on-line version made use of a homogeneous mixture Mie code for meteorological radiative transfer calculations.&lt;/p&gt;&lt;p&gt;We calculated a new lookup table for the extinction efficiency, absorption and scattering cross sections of each aerosol type. The new version of MESSY-JVAL uses GEM-MACH predicted aerosol size distributions, chemical composition and relative humidity in each vertical column at each time step as input, reads aerosol absorption and scattering cross section data from the new lookup table and calculates aerosol optical properties, that are then used to modify both photolysis and meteorological radiative transfer calculations.&lt;/p&gt;&lt;p&gt;In order to evaluate these modifications to the model, we performed a series of simulations with GEM-MACH with wildfire emissions inputs from the Canadian Forest Fire Emissions Prediction System (CFFEPS) and compared the model AOD output with satellite and AERONET (Aerosol Robotic Network) measurement data. Comparison of the hourly AERONET and monthly-averaged satellite AOD demonstrates major improvements in the revised model AOD predictions. The impact of the updated photolysis rates and meteorological radiative transfer calculations on predictions of oxidant mixing ratios and rates of pollutant oxidation (nitrogen dioxide conversion to nitric acid) will be assessed both within and below the forest fire plume.&lt;/p&gt;

Effect of sea breeze regime on aerosol optical properties over the city of Rome, Italy.

2020 ◽  
Author(s):  
Annalisa Di Bernardino ◽  
Anna Maria Iannarelli ◽  
Stefano Casadio ◽  
Gabriele Mevi ◽  
Monica Campanelli ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Air Quality ◽  
Sea Breeze ◽  
Coastal Areas ◽  
Horizontal Wind ◽  
Tyrrhenian Sea ◽  
Depth Analysis ◽  
The Impact ◽  
The City

&lt;p&gt;Mesoscale meteorological phenomena, such as sea-land breeze regime, strongly impact meteorological conditions of coastal areas, affecting wind intensity, moisture, heat and momentum fluxes and polluted air masses dispersion. This effect must be considered in order to correct design urban spaces, predict the possible influence of land use change on air pollution and climate change and, consequently, improve the quality of life and urban comfort.&lt;/p&gt;&lt;p&gt;In recent years, it has been shown that the breeze regime does not only affect microclimatic conditions but also air quality in coastal areas, because of the mixing of different types of aerosols and condensable gases. Moreover, the advection of marine, colder and more humid air leads to the decrease of the boundary layer height and, consequently, to the increase of the surface concentration of locally emitted pollutants, that are trapped within the boundary layer itself.&lt;/p&gt;&lt;p&gt;The effect of breeze regime is particularly interesting in coastal cities, where the sea breeze entails large modification of physical, optical, chemical, and hygroscopic properties of the urban aerosol.&lt;/p&gt;&lt;p&gt;In this work, we developed an approach to determine the breeze effect on aerosol in correspondence of the BAQUNIN [1] Super-site urban location, in the centre of Rome, Italy. The city is about 28 km far from the Tyrrhenian coast and is often exposed to sea-breeze circulation and to extreme aerosol events [2] [3].&lt;/p&gt;&lt;p&gt;In-situ measurements obtained from different remote sensing instruments are used: (i) vertical profile of horizontal wind velocity and direction by means of SODAR wind profiler; (ii) moisture, air temperature and wind speed from ground-based meteorological station; (iii) aerosol optical depth (AOD), height and evolution of the Boundary Layer from Raman and elastic LIDAR; (iv) precipitable water, AOD, &amp;#197;ngstr&amp;#246;m exponent (AE) and single-scattering albedo (SSA) from sun-photometer CIMEL [4], (v) AOD, AE and SSA from POM 01 L Prede sun-sky radiometer [5][6], (vi) superficial NO&lt;sub&gt;2&lt;/sub&gt; and formaldehyde amounts from PANDORA spectrometer [7], (vii) particulate matter (PM&lt;sub&gt;2.5 &lt;/sub&gt;and PM&lt;sub&gt;10&lt;/sub&gt;) concentrations from ground-based air quality station.&lt;/p&gt;&lt;p&gt;The investigation is focused on several days, during summer of 2019, characterized by anemological breeze regime conditions.&lt;/p&gt;&lt;p&gt;In this study, we present preliminary results aimed to the in-depth analysis of the effects of the breeze regime on the optical properties of aerosols in coastal, urban environment and the impact of the aerosol vertical stratification on ground-level PM concentrations.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;References:&lt;/p&gt;&lt;p&gt;[1] BAQUNIN Boundary-layer Air Quality-analysis Using Network of Instruments, www.baqunin.eu&lt;/p&gt;&lt;p&gt;[2] Petenko I. et al. (2011) &amp;#8220;Local circulation diurnal patterns and their relationship with large-scale flows in a coastal area of the Tyrrhenian sea&amp;#8221;, Boundary-Layer Meteorology, 139:353-366.&lt;/p&gt;&lt;p&gt;[3] Ciardini V. et al. (2012) &amp;#8220;Seasonal variability of tropospheric aerosols in Rome&amp;#8221;, Atmospheric Research, 118:205-214.&lt;/p&gt;&lt;p&gt;[4] AERONET, https://aeronet.gsfc.nasa.gov/new_web/index.html&lt;/p&gt;&lt;p&gt;[5] EUROSKYRAD http://www.euroskyrad.net/&lt;/p&gt;&lt;p&gt;[6] Campanelli M. et al. (2019) &amp;#8220;Aerosol optical characteristics in the urban area of Rome, Italy, and their impact on the UV index&amp;#8221;, Atmospheric Measurement Techniques Discussion.&lt;/p&gt;&lt;p&gt;[7] PGN, https://www.pandonia-global-network.org/&lt;/p&gt;

scholarly journals Wildfire particulate matter in Europe during summer 2003: meso-scale modeling of smoke emissions, transport and radiative effects

2007 ◽  
Vol 7 (2) ◽  
pp. 4705-4760 ◽  
Author(s):  
A. Hodzic ◽  
S. Madronich ◽  
B. Bohn ◽  
S. Massie ◽  
L. Menut ◽  
...  
Keyword(s):  
Optical Properties ◽  
Air Quality ◽  
Radiative Forcing ◽  
Anthropogenic Sources ◽  
Radiative Effects ◽  
Aerosol Optical Properties ◽  
Smoke Particles ◽  
Fire Source ◽  
Photolysis Rates ◽  
Meso Scale

Abstract. The present study investigates effects of wildfire emissions on air quality in Europe during an intense fire season that occurred in summer 2003. A meso-scale chemistry transport model CHIMERE is used, together with ground based and satellite aerosol optical measurements, to assess the dispersion of fire emissions and to quantify the associated radiative effects. The model has been improved to take into account the MODIS daily smoke emission inventory as well as the injection altitude of smoke particles. The simulated aerosol optical properties are inputted into a radiative transfer model to estimate (off-line) the effects of smoke particles on photolysis rates and atmospheric radiative forcing. We have found that wildfires generated comparable amounts of primary aerosol pollutants (220 kTons of PM2.5, fine particles) to anthropogenic sources during August 2003, and caused significant changes in aerosol optical properties not only close to the fire source regions, but also over a large part of Europe as a result of the long-range transport of smoke. Including these emissions into the model significantly improved its performance in simulating observed aerosol concentrations and optical properties. Quantitative comparison with MODIS and POLDER data during the major fire event (3–8 August) showed the ability of the model to reproduce high aerosol optical thickness (AOT) over Northern Europe caused by the advection of the smoke plume from the Portugal source region. Statistical analyses of model simulations showed a better agreement with observed AOT data at AERONET ground stations and suggest that wildfire emissions are responsible for a 30% enhancement in mean AOT values during the heat-wave episode. The implications for air quality over a large part of Europe are significant during this episode. First, directly, the modeled wildfire emissions caused an increase in average PM10 ground concentrations from 20 to 200%. The largest enhancement in PM10 concentrations stayed however confined within a 200 km area around the fire source locations and reached up to 40 μ g/m3. Second, indirectly, the presence of elevated smoke layers over Europe significantly altered atmospheric radiative properties: the model results imply a 10 to 30% decrease in photolysis rates and an increase in atmospheric radiative forcing of 10–35 Wm−2 during the period of strong fire influence throughout a large part of Europe. These results suggest that sporadic wildfire events may have significant effects on regional photochemistry and atmospheric stability, and need to be considered in current chemistry-transport models.

scholarly journals Impacts of Anthropogenic Factors on Urban Air Quality in Lagos Metropolis

2019 ◽  
Vol 11 (2) ◽  
pp. 35
Author(s):  
Peter Nkashi AGAN
Keyword(s):  
Land Use ◽  
Air Quality ◽  
Raw Materials ◽  
Anthropogenic Activities ◽  
Anthropogenic Factors ◽  
Land Uses ◽  
Residential Areas ◽  
Industrial Land ◽  
The City

Land use is the utilization and reordering of land cover for human comfort. This process disrupts the pristine state of the environment reducing the quality of environmental receptors like water, air, vegetation etc. Air pollution is introduced into the environment as a result of anthropogenic activities from commercial, industrial and residential areas. These activities are burning of fossil fuels for power generation, transport of goods and services, valorization of raw materials into finished products, bush burning, use of gas cookers, generators and electric stove etc. The introduction of pollutants into the planetary layer of the atmosphere has impacted negatively on the quality of the environment posing threat to humans and the survival of the ecosystem. In Lagos metropolis, commercial activities and high population densities have caused elevated levels of pollution in the city. This study aimed to investigate the spatial distribution of pollutant in Lagos metropolis with a view to revealing the marked spatial/temporal difference in pollutants levels over residential, commercial and industrial land uses. Commercial and industrial land uses revealed higher levels of pollutants than the residential areas. Pearson product moment correlation coefficients revealed strong positive relationship between land use and air quality in the city.

scholarly journals Identifying Chemical Aerosol Signatures using Optical Suborbital Observations: How much can optical properties tell us about aerosol composition?

2021 ◽  
Author(s):  
Meloë S. F. Kacenelenbogen ◽  
Qian Tan ◽  
Sharon P. Burton ◽  
Otto P. Hasekamp ◽  
Karl D. Froyd ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Optical Properties ◽  
Air Quality ◽  
Chemical Transport ◽  
Single Scattering ◽  
Single Scattering Albedo ◽  
Aerosol Optical Properties ◽  
Aerosol Composition ◽  
Ångström Exponent

Abstract. Improvements in air quality and Earth’s climate predictions require improvements of the aerosol speciation in chemical transport models, using observational constraints. Aerosol speciation (e.g., organic aerosols, black carbon, sulfate, nitrate, ammonium, dust or sea salt) is typically determined using in situ instrumentation. Continuous, routine surface network aerosol composition measurements are not uniformly widespread over the globe. Satellites, on the other hand, can provide a maximum coverage of the horizontal and vertical atmosphere but observe aerosol optical properties (and not aerosol speciation) based on remote sensing instrumentation. Combinations of satellite-derived aerosol optical properties can inform on air mass aerosol types (AMTs e.g., clean marine, dust, polluted continental). However, these AMTs are subjectively defined, might often be misclassified and are hard to relate to the critical parameters that need to be refined in models. In this paper, we derive AMTs that are more directly related to sources and hence to speciation. They are defined, characterized, and derived using simultaneous in situ gas-phase, chemical and optical instruments on the same aircraft during the Study of Emissions and Atmospheric Composition, Clouds, and Climate Coupling by Regional Surveys (SEAC4RS, US, summer of 2013). First, we prescribe well-informed AMTs that display distinct aerosol chemical and optical signatures to act as a training AMT dataset. These in situ observations reduce the errors and ambiguities in the selection of the AMT training dataset. We also investigate the relative skill of various combinations of aerosol optical properties to define AMTs and how much these optical properties can capture dominant aerosol speciation. We find distinct optical signatures for biomass burning (from agricultural or wildfires), biogenic and dust-influence AMTs. Useful aerosol optical properties to characterize these signatures are the extinction angstrom exponent (EAE), the single scattering albedo, the difference of single scattering albedo in two wavelengths, the absorption coefficient, the absorption angstrom exponent (AAE), and the real part of the refractive index (RRI). We find that all four AMTs studied when prescribed using mostly airborne in situ gas measurements, can be successfully extracted from at least three combinations of airborne in situ aerosol optical properties (e.g., EAE, AAE and RRI) over the US during SEAC4RS. However, we find that the optically based classifications for BB from agricultural fires and polluted dust include a large percentage of misclassifications that limit the usefulness of results relating to those classes. The technique and results presented in this study are suitable to develop a representative, robust and diverse source-based AMT database. This database could then be used for widespread retrievals of AMTs using existing and future remote sensing suborbital instruments/networks. Ultimately, it has the potential to provide a much broader observational aerosol data set to evaluate chemical transport and air quality models than is currently available by direct in situ measurements. This study illustrates how essential it is to explore existing airborne datasets to bridge chemical and optical signatures of different AMTs, before the implementation of future spaceborne missions (e.g., the next generation of Earth Observing System (EOS) satellites addressing Aerosol, Cloud, Convection and Precipitation (ACCP) designated observables).

scholarly journals Wildfire particulate matter in Europe during summer 2003: meso-scale modeling of smoke emissions, transport and radiative effects

2007 ◽  
Vol 7 (15) ◽  
pp. 4043-4064 ◽  
Author(s):  
A. Hodzic ◽  
S. Madronich ◽  
B. Bohn ◽  
S. Massie ◽  
L. Menut ◽  
...  
Keyword(s):  
Optical Properties ◽  
Air Quality ◽  
Radiative Forcing ◽  
Anthropogenic Sources ◽  
Radiative Effects ◽  
Aerosol Optical Properties ◽  
Smoke Particles ◽  
Fire Source ◽  
Photolysis Rates ◽  
Meso Scale

Abstract. The present study investigates effects of wildfire emissions on air quality in Europe during an intense fire season that occurred in summer 2003. A meso-scale chemistry transport model CHIMERE is used, together with ground based and satellite aerosol optical measurements, to assess the dispersion of fire emissions and to quantify the associated radiative effects. The model has been improved to take into account a MODIS-derived daily smoke emission inventory as well as the injection altitude of smoke particles. The simulated aerosol optical properties are put into a radiative transfer model to estimate (off-line) the effects of smoke particles on photolysis rates and atmospheric radiative forcing. We have found that the simulated wildfires generated comparable amounts of primary aerosol pollutants (130 kTons of PM2.5, fine particles) to anthropogenic sources during August 2003, and caused significant changes in aerosol optical properties not only close to the fire source regions, but also over a large part of Europe as a result of the long-range transport of the smoke. Including these emissions into the model significantly improved its performance in simulating observed aerosol concentrations and optical properties. Quantitative comparison with MODIS and POLDER data during the major fire event (3–8 August 2003) showed the ability of the model to reproduce high aerosol optical thickness (AOT) over Northern Europe caused by the advection of the smoke plume from the Portugal source region. Although there was a fairly good spatial agreement with satellite data (correlation coefficients ranging from 0.4 to 0.9), the temporal variability of AOT data at specific AERONET locations was not well captured by the model. Statistical analyses of model-simulated AOT data at AERONET ground stations showed a significant decrease in the model biases suggesting that wildfire emissions are responsible for a 30% enhancement in mean AOT values during the heat-wave episode. The implications for air quality over a large part of Europe are significant during this episode. First, directly, the modeled wildfire emissions caused an increase in average PM2.5 ground concentrations from 20 to 200%. The largest enhancement in PM2.5 concentrations stayed, however, confined within a 200 km area around the fire source locations and reached up to 40 μg/m³. Second, indirectly, the presence of elevated smoke layers over Europe significantly altered atmospheric radiative properties: the model results imply a 10 to 30% decrease in photolysis rates and an increase in atmospheric radiative forcing of 10–35 W m−2 during the period of strong fire influence throughout a large part of Europe. These results suggest that sporadic wildfire events may have significant effects on regional photochemistry and atmospheric stability, and need to be considered in current chemistry-transport models.

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