Aerosol Measurement

A comparison between various methods for real-time measurements of lung deposited surface area (LDSA) using spherical particles and powder dust with specific surface area ranging from 0.03 to 112 m 2 g -1 was conducted. LDSA concentrations measured directly using Nanoparticle Surface Area Monitor (NSAM) and Aerotrak and were compared to LDSA concentrations recalculated from size distribution measurements using Electrical Low Pressure Impactor (ELPI) and Fast Mobility Particle Sizer (FMPS). FMPS and ELPI measurements were also compared to dust surface area concentrations estimated from gravimetrical filter measurements and specific surface areas. Measurement of LDSA showed very good correlation in measurements of spherical particles (R 2 > 0.97, Ratio 1.0 to 1.04). High surface area nanomaterial powders showed a fairly reliable correlation between NSAM and Aerotrak (R 2 0.73-0.93) and a material-dependent offset in the ratios (1.04-2.8). However, the correlation and ratio were inconsistent for lower LDSA concentrations. Similar levels of correlation were observed for the NSAM and the FMPS for high surface area materials, but with the FMPS overestimating the LDSA concentration. The ELPI showed good correlation with NSAM data for high LDSA materials (R 2 0.87-0.93), but not for lower LDSA concentrations (R 2 0.50-0.72). Comparisons of respirable dust surface area from ELPI data correlated well (R 2 > 0.98) with that calculated from filter samples, but materials-specific exceptions were present. We conclude that there is currently insufficient reliability and comparability between methods in the measurement of LDSA concentrations. Further development is required to enable use of LDSA for reliable dose metric and regulatory enforcement of exposure.

We developed a new methodology for the improved identification of particle microphysical parameters (PMPs) from multiwavelength lidar measurements. The underlying problem is underdetermined and relates to the class of ill-posed problems. In this study, we apply our new methodology to lidar measurements. We investigate how results obtained for typical aerosol mixtures (AMs) in the atmosphere can be improved if information about aerosol types and the number of aerosol types in such an AM is available. We have developed a methodology of Aerosol Typing from Linear estimations for the Analytical Separation (ATLAS) of complex aerosol mixtures in the first part of our study. ATLAS allows us to decompose a complex AM into individual aerosol types in terms of optical data measured by lidar. Optical data derived for individual aerosol types are then separately considered and inverted into PMPs with our automated unsupervised data-inversion methodology TiARA (Tikhonov Advanced Regularization Algorithm). We apply our new two-stage (ATLAS-TiARA) synergetic methodology to three lidar-measurement cases corresponding to two-, three-, and four-component AMs. The measurements we use for this study were carried out in the frameworks of the ORACLES-2016 and SHADOW field campaigns and lidar observations at the University of Lille (France), respectively. Results of the new methodology agree with results obtained with data collected by in situ instruments during the ORACLES-2016 campaign. Deviations of number concentration and single-scattering albedo at 532 nm retrieved with the new methodology from respective in situ measurements do not exceed 25% and 0.05, respectively. We find both fine-and coarse-mode particles from all three measurement cases. Fine-mode particles are represented by urban and smoke (haze), whereas coarse-mode particles can be attributed to dust, marine, and pollen aerosols. In summary, the methodology allows us to obtain a more detailed insight into microphysical particle properties.

A comprehensive comparison of more than 70000 synchronous 1-minute aerosol optical depth (AOD) data from three Global Atmosphere Watch-Precision Filter Radiometer (GAW-PFR) and 15 Aerosol Robotic Network-Cimel (AERONET-Cimel) radiometers was performed for the four nearby wavelengths (380, 440, 500 and 870 nm) in the period 2005-2015. The goal of this study is to assess whether, despite the marked differences between both networks and the number of instruments used, their long term AOD data are comparable and consistent. AOD traceability established by the World Meteorological Organization (WMO) consists in determining the percentage of synchronous data within specific limits. If, at least, 95 % of the AOD differences of an instrument compared to the WMO standards lie within these limits, both data populations are considered equivalent. The percentage of traceable data is 92.7 % (380 nm), 95.7 % (440 nm), 95.8 % (500 nm) and 98.0 % (870 nm). When small misalignments in GAW-PFR sun-pointing were fixed (period 2010-2015), the percentage of traceable data increased. The contribution of calibration related aspects to comparison outside the 95 % traceability limits is insignificant in all channels, except in 380 nm. The simultaneous failure of both cloud screening algorithms might occur only under the presence of cirrus, or altostratus clouds on the top of a dust-laden Saharan air layer. Differences in the calculation of the optical depth contribution due to Rayleigh scattering, and O 3 and NO 2 absorption have a negligible impact. For AOD > 0.1, a nonnegligible percentage (∼ 1.9 %) of the AOD data outside the 95 % traceability limits at 380 nm can be partly assigned to the different field of view of the instruments. The comparison of the Angström exponent (AE) shows that under non-pristine conditions (AOD > 0.03 and AE < 1) the AE differences remain < 0.1. The excellent traceability in this study has been obtained using well calibrated Master instruments.

The objectives of this study were to measure levels of particulate matter (PM) in mechanically ventilated buildings and to improve understanding of filtration requirements to reduce exposure. With the use of an Ultra High Sensitivity Aerosol Spectrometer and an Aerodyne Mass Spectrometer, ultrafine (0.055-0.1 µm) and fine (0.1-0.7 µm) indoor and outdoor PM was measured as a function of time in an office, a university building, and two elementary schools. Indoor particle levels were highly correlated with outdoor levels. Indoor and outdoor number concentrations in Denver were higher than those in Boulder, with the highest number concentrations occurring during summer and fall. The ratio of indoor-to-outdoor (I/O) PM was weakly but positively correlated with the amount of ventilation provided to the indoor environment, did not vary much with particle size (ranged between 0.48 and 0.63 for the entire size range), and was similar for each period of the week (weekend vs. weekday, night vs. day). Regression analyses showed that ultrafine indoor PM baseline concentrations were higher at night from nighttime infiltration. A lag time was observed between outdoor and indoor measurements. Weekday days had the shortest lag time of 11 min, and weekend nighttime lags when the HVAC was not in use were 50 to 148 min. Indoor-outdoor PM concentration plots showed ultrafine PM was more correlated compared to fine, and especially when the HVAC system was on. Finally, AMS data showed that most of the PM was organic, with occasional nitrate events occurring outdoors. During nitrate events, there were less indoor particles detected, indicating a loss of particulate phase nitrate. The results from this study show that improved filtration is warranted in mechanically ventilated buildings, particularly for ultrafine particles, and that nighttime infiltration is significant depending on the building design.

This paper present first ever vertically distributed aircraft measurements of atmospheric aerosols over Pokhara Valley in Nepal. The Himalayan region is generally polluted but only few detailed measurements of the pollution exists. Nepal, being situated in Central Himalayas, is a desirable region for conducting such measurements, in order to understand the sources and transport or aerosols in the region. Therefore, the manuscript is of definite value and well suited for ACP. The measurements seem to be well conducted, and complemented with appropriate data from ground based AODmeasurements as well as satellite and model results. There are few issues with the

Ice formation in orographic mixed-phase clouds can enhance precipitation and depends on the type of aerosols that serve as ice nucleating particles (INPs). The resulting precipitation from these clouds is a viable source of water, especially for regions such as the California Sierra Nevada. Thus, a better understanding of the sources of INPs that impact orographic clouds is important for assessing water availability in California. This study presents a multi-site, multiyear analysis of single-particle insoluble residues in precipitation samples that likely influenced cloud ice and precipitation formation above Yosemite National Park. Dust and biological particles represented the dominant fraction of the residues (64% on average). Cloud glaciation, determined using satellite observations, not only depended on high cloud tops (> 5.9 km) and low temperatures (< −23°C), but also on the presence of what were likely dust and biological INPs. The greatest prevalence of ice-phase clouds occurred in conjunction with biologically-rich residues and mineral dust rich in calcium, followed by iron and aluminosilicates. Dust and biological particles are known to be efficient INPs, thus these residues likely influenced ice formation in clouds above the sites and subsequent precipitation quantities reaching the surface during events with similar meteorology. The goal of this study is to use precipitation chemistry information to gain a better understanding of the potential sources of INPs in the south-central Sierra Nevada, where cloud-aerosol-precipitation interactions are poorly understood and where mixed-phase orographic clouds represent a key element in the generation of precipitation and thus the water supply in California.

Mineral dust aerosols often observed over California in winter and spring, associated with long-range transport from Asia and the Sahara, have been linked to enhanced precipitation based on observations. Local anthropogenic pollution, on the other hand, was shown in previous observational and modeling studies to reduce precipitation. Here we incorporate recent developments in ice nucleation parameterizations to link aerosols with ice crystal formation in a spectralbin cloud microphysical model coupled with the Weather Research and Forecasting (WRF) model in order to examine the relative and combined impacts of dust and local pollution particles on cloud properties and precipitation type and intensity. Simulations are carried out for two cloud cases (from the CalWater 2011 field campaign) with contrasting meteorology and cloud dynamics that occurred on 16 February (FEB16) and 2 March (MAR02). In both cases, observations show the presence of dust and biological particles in a relative pristine environment. The simulated cloud microphysical properties and precipitation show reasonable agreement with aircraft and surface measurements. Model sensitivity experiments indicate that in the pristine environment, the dust and biological aerosol layers increase the accumulated precipitation by 10-20 % from the Central Valley to the Sierra Nevada for both FEB16 and MAR02 due to a ∼40 % increase in snow formation, validating the observational hypothesis. Model results show that local pollution increases precipitation over the windward slope of the mountains by a few percent due to increased snow formation when dust is present, but reduces precipitation by 5-8 % if dust is removed on FEB16. The effects of local pollution on cloud microphysics and precipitation strongly depend on meteorology, including cloud dynamics and the strength of the Sierra Barrier Jet. This study further underscores the importance of the interactions between local pollution, dust, and environmental conditions for assessing aerosol effects on cold-season precipitation in California. 1 Introduction Precipitation is an important process that regulates atmospheric moisture, heat budgets, and local hydrological cycles. Affected by many factors such as large-scale dynamics, solar heating, and aerosol particles (Shen et al., 2010; Rosenfeld

An atmospheric pressure aerosol-based wet thin film coating technique called the nFOG is characterized and applied in polymer film coatings. In the nFOG, a fog of droplets is formed by two air-assist atomizers oriented toward each other inside a deposition chamber. The droplets settle gravitationally and deposit on a substrate, forming a wet film. In this study, the continuous deposition mode of the nFOG is explored. We determined the size distribution of water droplets inside the chamber in a wide side range of 0.1-100 lm and on the substrate using aerosol measurement instruments and optical microscopy, respectively. The droplet size distribution was found to be bimodal with droplets of approximately 30-50 lm contributing the most to the mass of the formed wet film. The complementary measurement methods allow us to estimate the role of different droplet deposition mechanisms. The obtained results suggest that the deposition velocity of the droplets is lower than the calculated terminal settling velocity, likely due to the flow fields inside the chamber. Furthermore, the mass flux of the droplets onto the substrate is determined to be in the order of 1 g/m 3 s, corresponding to a wet film growth rate of 1 lm/s. Finally, the nFOG technique is demonstrated by preparing polymer films with thicknesses in the range of approximately 0.1-20 lm.

An atmospheric pressure aerosol-based wet thin film coating technique called the nFOG is characterized and applied in polymer film coatings. In the nFOG, a fog of droplets is formed by two air-assist atomizers oriented toward each other inside a deposition chamber. The droplets settle gravitationally and deposit on a substrate, forming a wet film. In this study, the continuous deposition mode of the nFOG is explored. We determined the size distribution of water droplets inside the chamber in a wide side range of 0.1-100 lm and on the substrate using aerosol measurement instruments and optical microscopy, respectively. The droplet size distribution was found to be bimodal with droplets of approximately 30-50 lm contributing the most to the mass of the formed wet film. The complementary measurement methods allow us to estimate the role of different droplet deposition mechanisms. The obtained results suggest that the deposition velocity of the droplets is lower than the calculated terminal settling velocity, likely due to the flow fields inside the chamber. Furthermore, the mass flux of the droplets onto the substrate is determined to be in the order of 1 g/m 3 s, corresponding to a wet film growth rate of 1 lm/s. Finally, the nFOG technique is demonstrated by preparing polymer films with thicknesses in the range of approximately 0.1-20 lm.

Very little is known about the elemental composition and possible sources of fine aerosol particles from Mediterranean megacities. Fine aerosol particles were collected at a residential-industrial area in Greater Cairo, Egypt, during the period from October 2010 to May 2011. The elemental compositions of the collected samples were quantified by using a homemade energy dispersive x-ray fluorescence spectrometer, whereas black carbon was quantified by a black smoke detector. Fifteen elements have been quantified. Of these constituents, Ca, C, Cl, S, and Fe had the highest concentrations: greater than 1 µg m −3. The overall mean mass concentration of the collected samples equals 70 µg m −3 ; this value exceeds the European Union annual Air Quality Standard levels. The individual elemental concentrations of the fine particles were found to be dominated by elements linked to mineral dust. Most of the monthly variations of elemental concentrations can be attributed to seasonal meteorological conditions. Other possible sources were vehicle-exhaust and industrial activities. The results pinpoint the problem of identifying different sources when one source, in this case, the nearby deserts, is dominant. The results from this study contribute to the growing knowledge of concentrations, composition, and possible sources of ambient fine particulate matter.

In this paper we demonstrate the utility of the Polar Ozone and Aerosol Measurement (POAM) III data for providing semiglobal three-dimensional ozone fields during the Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment (SOLVE) winter. As a solar occultation instrument, POAM III measurements were limited to latitudes of 63°N to 68°N during the SOLVE campaign but covered a wide range of potential vorticity. Using established mapping techniques, we have used the relation between potential vorticity and ozone measured by POAM III to calculate threedimensional ozone mixing ratio fields throughout the Northern Hemisphere on a daily basis during the 1999/2000 winter. To validate the results, we have extensively compared profiles obtained from ozonesondes and the Halogen Occultation Experiment to the proxy O 3 interpolated horizontally and vertically to the correlative measurement locations. On average, the proxy O 3 agrees with the correlative observations to better than $5%, at potential temperatures below about 900 K and latitudes above about 30°N, demonstrating the reliability of the reconstructed O 3 fields in these regions. We discuss the application of the POAM proxy ozone profiles for calculating photolysis rates along the ER-2 and DC-8 flight tracks during the SOLVE campaign, and we present a qualitative picture of the evolution of polar stratospheric ozone throughout the winter.

Asian Dust particles originated from the deserts and loess areas of the Asian continent are often transported over Korea, Japan, and the North Pacific Ocean during spring season. Major air mass pathway of Asian dust storm to Korea is from either northwestern Chinese desert regions or northeastern Chinese sandy areas. The local atmospheric environment condition in Korea is greatly impacted by Asian dust particles transported by prevailing westerly wind. Since these Asian dust particles pass through heavily populated urban and industrial areas in China before it reach Korean peninsular, their physical, chemical and optical properties vary depending on the atmospheric conditions and air mass pathway characteristics. An integrated system approach has been adopted at the Advanced Environment Monitoring Research Center (ADEMRC), Gwangju Institute Science and Technology (GIST), Korea for effective monitoring of atmospheric aerosols utilizing various in-situ and optical remote sensing methods, which include a multi-channel Raman LIDAR system, sunphotometer, satellite, and in-situ instruments. Results from recent studies on impacts of Asian dust particles on local air quality and radiative forcing over Korea are summarized here.

In order to reduce uncertainty in the estimation of Direct Aerosol Radiative Forcing (DARF), it is important to improve the estimation of the single scattering albedo (SSA). In this study, we propose a new data processing method to improve SSA retrievals for the SKYNET sky radiometer network, which is one of the growing number of networks of sun-sky photometers, such as NASA AERONET and others. There are several reports that SSA values from SKYNET have a bias compared to those from AERONET, which is regarded to be the most accurate due to its rigorous calibration routines and data quality and cloud screening algorithms. We investigated possible causes of errors in SSA that might explain the known biases through sensitivity experiments using a numerical model, and also using real data at the SKYNET sites at Pune (18.616 • N/73.800 • E) in India and Beijing (39.586 • N/116.229 • E) in China. Sensitivity experiments showed that an uncertainty of the order of ±0.03 in the SSA value can be caused by a possible error in the ground surface albedo or solid view angle assumed for each observation site. Another candidate for possible error in the SSA was found in cirrus contamination generated by imperfect cloud screening in the SKYNET data processing. Therefore, we developed a new data quality control method to get rid of low quality or cloud contamination data, and we applied this method to the real observation data at the Pune site in SKYNET. After applying this method to the observation data, we were able to screen out a large amount of cirruscontaminated data and to reduce the deviation in the SSA value from that of AERONET. We then estimated DARF using data screened by our new method. The result showed that the method significantly reduced the difference of 5 W m −2 that existed between the SKYNET and AERONET values of DARF before screening. The present study also suggests the necessity of preparing suitable a priori information on the distribution of coarse particles ranging in radius between 10 µm and 30 µm for the analysis of heavily dust-laden atmospheric cases.

We study the interactions between atmospheric boundary layer (ABL) dynamics and atmospheric chemistry using a mixed-layer model (MXLCH) coupled to chemical reaction schemes. Guided by both atmospheric and chemical measurements obtained during the DOMINO campaign (2008), numerical experiments are performed to study the role of ABL dynamics and the accuracy of chemical schemes with different complexity: MOZART-4 and a reduced mechanism of this chemical system. Both schemes produce satisfactory results, indicating that the reduced scheme is capable of reproducing the O 3-NO x-VOC-HO x diurnal cycle during conditions characterised by a low NO x regime and small O 3 tendencies (less than 1 ppb per hour). By focussing on the budget equations of chemical species in the mixed-layer model, we show that for species like O 3 , NO and NO 2 , the influence of entrainment and boundary layer growth is of the same order as chemical production/loss. This indicates that an accurate representation of ABL processes is crucial in understanding the daily cycle of chemical species. By comparing the time scales of chemical reactive species with the mixing time scale of turbulence, we propose a classification based on the Damköhler number to further determine the importance of dynamics on chemistry during field campaigns. Our findings advocate an integrated approach, simultaneously solving the ABL dynamics and chemical reactions, in order to obtain a better understanding of chemical pathways and processes and the interpretation of the results obtained during measurement campaigns. ACPD 12, 6519-6550, 2012 Boundary layer chemistry and dynamics during DOMINO B. J. H. van Stratum et al.

To study the impact of fireworks (FW) events on air quality, aerosol particles from FW displays were measured using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and collocated instruments during the Independence Day (July 4, 2017) holiday period at Albany, NY, USA. The FW influenced periods were identified using potassium ion (K +) signals in the aerosol mass spectra. The FW influenced peak mass concentration of submicron particles (PM 1 , or particles with aerodynamic diameter less than 1 micron) measured at the uptown site (approximately 8 km from the FW launch location) was 61.8 μg m-3. The Independence Day FW events resulted in significant increases in concentrations of both organic and inorganic chemical components, including potassium, sulfate and chloride. An FW-related oxidized organic aerosol factor (FW-OOA) was identified during the most intense FW event of the measurement period. The intense emission of FW particles from the Independence Day celebration contributed about 77% (36.3 μg m-3) of total PM 1 (47.0 μg m-3) measured at the uptown site during Independence Day FW significantly influenced period (07/04 23:00-07/05 03:00). A collocated wind LiDAR at the uptown site measured atmospheric transport characteristics during the night of July 4/5. The low observed winds and high aerosol emissions highlight the significant episodic influence of FW burning on fine aerosol mass concentration and chemical characteristics while large numbers of people were clustered together and breathing the outdoor air.

The variability of precipitation and water supply along the U.S. West Coast creates major challenges to the region’s economy and environment, as evidenced by the recent California drought. This variability is strongly influenced by atmospheric rivers (ARs), which deliver much of the precipitation along the U.S. West Coast and can cause flooding, and by aerosols (from local sources and transported from remote continents and oceans) that modulate clouds and precipitation. A better understanding of these processes is needed to reduce uncertainties in weather predictions and climate projections of droughts and floods, both now and under changing climate conditions. To address these gaps, a group of meteorologists, hydrologists, climate scientists, atmospheric chemists, and oceanographers have created an interdisciplinary research effort, with support from multiple agencies. From 2009 to 2011 a series of field campaigns [California Water Service (CalWater) 1] collected atmospheric chemis...

Resumo Este trabalho possui dois objetivos principais, o primeiro é apresentar uma descrição de como o modelo atmosférico BRAMS foi estruturado com o intuito de capacitá-lo a simular a emissão, dispersão e sedimentação de cinzas vulcânicas; o segundo é fazer uma análise de sensibilidade com relação a diversas configurações do modelo, com o intuito de obter uma configuração adequada para prever a concentração de cinzas vulcânicas após eventos eruptivos. Avaliando os resultados do modelo com dados observados, principalmente com relação ao satélite CALIPSO, concluiu-se que o modelo BRAMS foi capaz de simular e prever com relativa precisão a posição e concentração das cinzas vulcânicas na atmosfera.

An atmospheric pressure aerosol-based wet thin film coating technique called the nFOG is characterized and applied in polymer film coatings. In the nFOG, a fog of droplets is formed by two air-assist atomizers oriented toward each other inside a deposition chamber. The droplets settle gravitationally and deposit on a substrate, forming a wet film. In this study, the continuous deposition mode of the nFOG is explored. We determined the size distribution of water droplets inside the chamber in a wide side range of 0.1-100 lm and on the substrate using aerosol measurement instruments and optical microscopy, respectively. The droplet size distribution was found to be bimodal with droplets of approximately 30-50 lm contributing the most to the mass of the formed wet film. The complementary measurement methods allow us to estimate the role of different droplet deposition mechanisms. The obtained results suggest that the deposition velocity of the droplets is lower than the calculated terminal settling velocity, likely due to the flow fields inside the chamber. Furthermore, the mass flux of the droplets onto the substrate is determined to be in the order of 1 g/m 3 s, corresponding to a wet film growth rate of 1 lm/s. Finally, the nFOG technique is demonstrated by preparing polymer films with thicknesses in the range of approximately 0.1-20 lm.

Cultural heritage constitutive materials can provide excellent substrates for microbial colonization, highly influenced by thermo-hygrometric parameters. In cultural heritage-related environments, a detrimental microbial load may be present both on manufacts surface and in the aerosol. In this study, bacterial and fungal colonisation has been investigated in three Sicilian confined environments (archive, cave and hypogea), each with peculiar structures and different thermo-hygrometric parameters. Particular attention has been paid to microorganisms able to induce artifacts biodeterioration and to release biological particles in the aerosol (spores, cellular debrides, toxins and allergens) potentially dangerous for the human health (visitors/users). Results provided information on the composition of the biological consortia, highlighting also the symbiotic relationships between micro (cyanobacteria, bacteria and fungi) and macro-organisms (plants, bryophyte and insects). The results of this integrated approach, including molecular biology techniques, are essential for a complete understanding of both microbial colonization of the cultural objects and the potential relationship with illness to human.

The aerosol properties of the atmosphere were obtained within the framework of the AERONET program at the Moscow State University Meteorological Observatory (Moscow MSU MO) over 2001–2014 period. The quality data control has revealed the necessity of their additional cloud and NO&lt;sub&gt;2&lt;/sub&gt; correction. The application of cloud correction according to hourly visual cloud observations provides a decrease in average aerosol optical thickness (AOT) at 500 nm of up to 0.03 compared with the standard dataset. We also show that the additional NO&lt;sub&gt;2&lt;/sub&gt; correction of the AERONET data is needed in large megalopolis, like Moscow, with 12 million residents and the…

The objectives of 7-SEAS/BASELInE (Seven SouthEast Asian Studies/Biomass-burning Aerosols & Stratocumulus Environment: Lifecycles & Interactions Experiment) campaigns in spring 2013-2015 were to synergize measurements from uniquely distributed ground-based networks (e.g., AERONET, MPLNET) and sophisticated platforms (e.g., SMARTLabs, regional contributing instruments), along with satellite observations/retrievals and regional atmospheric transport/chemical models to establish a critically needed database, and to advance our understanding of biomass-burning aerosols and trace gases in Southeast Asia (SEA). We present a satellite-surface perspective of 7-SEAS/BASELInE and highlight scientific findings concerning: (1) regional meteorology of moisture fields conducive to the production and maintenance of low-level stratiform clouds over land, (2) atmospheric composition in a biomass-burning environment, particularly tracers/markers to serve as important indicators for assessing the state and evolution of atmospheric constituents, (3) applications of remote sensing to air quality and impact on radiative energetics, examining the effect of diurnal variability of boundary-layer height on aerosol loading, (4) aerosol hygroscopicity and ground-based cloud radar measurements in aerosol-cloud processes by advanced cloud ensemble models, and (5) implications of air quality, in terms of toxicity of nanoparticles and trace gases, to human health. This volume is the third 7-SEAS special issue (after

Vehicle exhaust and cooking emissions are closely related to the daily life of city dwellers. Here, we defined the secondary organic aerosols (SOAs) derived from vehicle exhaust and cooking emissions as "urban-lifestyle SOAs" and simulated their formation using a Gothenburg potential aerosol mass reactor (Go:PAM). The vehicle exhaust and cooking emissions were separately simulated, and their samples were defined as "vehicle group" and "cooking group", respectively. After samples had been aged under 0.3-5.5 d of equivalent photochemical age, these two urban-lifestyle SOAs showed markedly distinct features in the SOA mass growth potential, oxidation pathways, and mass spectra. The SOA/POA (primary organic aerosol) mass ratios of vehicle groups (107) were 44 times larger than those of cooking groups (2.38) at about 2 d of equivalent photochemical age, according to the measurement of scanning mobility particle sizer (SMPS). A high-resolution time-of-flight aerosol mass spectrometer was used to perform a deeper analysis. It revealed that organics from the vehicle may undergo the alcohol and/or peroxide and carboxylic acid oxidation pathway to produce abundant less and more oxidized oxygenated OAs (LO-OOAs and MO-OOAs), and only a few primary hydrocarbon-like organic aerosols (HOAs) remain unaged. In contrast, organics from cooking may undergo the alcohol and/or peroxide oxidation pathway to produce moderate LO-OOAs, and comparable primary cooking organic aerosols (COAs) remain unaged. Our findings provide an insight into atmospheric contributions and chemical evolutions for urban-lifestyle SOAs, which could greatly influence the air quality and health risk assessments in urban areas.

In this paper we demonstrate the utility of the Polar Ozone and Aerosol Measurement (POAM) III data for providing semiglobal three-dimensional ozone fields during the Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment (SOLVE) winter. As a solar occultation instrument, POAM III measurements were limited to latitudes of 63°N to 68°N during the SOLVE campaign but covered a wide range of potential vorticity. Using established mapping techniques, we have used the relation between potential vorticity and ozone measured by POAM III to calculate threedimensional ozone mixing ratio fields throughout the Northern Hemisphere on a daily basis during the 1999/2000 winter. To validate the results, we have extensively compared profiles obtained from ozonesondes and the Halogen Occultation Experiment to the proxy O 3 interpolated horizontally and vertically to the correlative measurement locations. On average, the proxy O 3 agrees with the correlative observations to better than $5%, at potential temperatures below about 900 K and latitudes above about 30°N, demonstrating the reliability of the reconstructed O 3 fields in these regions. We discuss the application of the POAM proxy ozone profiles for calculating photolysis rates along the ER-2 and DC-8 flight tracks during the SOLVE campaign, and we present a qualitative picture of the evolution of polar stratospheric ozone throughout the winter.

Through wind erosion, tons of mineral dust are carried into the atmosphere, interfering with terrestrial radiative balance, biogeochemical cycles, precipitation patterns, human health and air pollution. Given the climatic changes that can alter these mechanisms and patterns, it is necessary to expand this knowledge and, therefore, we present a review of the main tools used in the study of mineral dust, either by in situ collection or using solar photometers, such as Microtops II. We also present the determination of the provenance through techniques such as the isotopic signature of strontium and neodymium, and by atmospheric modeling, by the HYSPLIT system. Present and ancient examples of intercontinental transport are reported data are reported with data that can fill gaps in the climate history can fill gaps in the climate history. We intend for this review of the state of the art to contribute to the dissemination of knowledge and, above all, to create opportunities for developing research projects on aerosols. Associação entre poeira mineral e clima AssociAtion between minerAl dust And climAte elAine Alves dos sAntos 1 , clAudio de morisson vAleriAno 2 , corbiniAno silvA 3

The objectives of this study were to measure levels of particulate matter (PM) in mechanically ventilated buildings and to improve understanding of filtration requirements to reduce exposure. With the use of an Ultra High Sensitivity Aerosol Spectrometer and an Aerodyne Mass Spectrometer, ultrafine (0.055-0.1 µm) and fine (0.1-0.7 µm) indoor and outdoor PM was measured as a function of time in an office, a university building, and two elementary schools. Indoor particle levels were highly correlated with outdoor levels. Indoor and outdoor number concentrations in Denver were higher than those in Boulder, with the highest number concentrations occurring during summer and fall. The ratio of indoor-to-outdoor (I/O) PM was weakly but positively correlated with the amount of ventilation provided to the indoor environment, did not vary much with particle size (ranged between 0.48 and 0.63 for the entire size range), and was similar for each period of the week (weekend vs. weekday, night vs. day). Regression analyses showed that ultrafine indoor PM baseline concentrations were higher at night from nighttime infiltration. A lag time was observed between outdoor and indoor measurements. Weekday days had the shortest lag time of 11 min, and weekend nighttime lags when the HVAC was not in use were 50 to 148 min. Indoor-outdoor PM concentration plots showed ultrafine PM was more correlated compared to fine, and especially when the HVAC system was on. Finally, AMS data showed that most of the PM was organic, with occasional nitrate events occurring outdoors. During nitrate events, there were less indoor particles detected, indicating a loss of particulate phase nitrate. The results from this study show that improved filtration is warranted in mechanically ventilated buildings, particularly for ultrafine particles, and that nighttime infiltration is significant depending on the building design.

This paper describes the first part of a project conducted to evaluate the trace element composition of atmospheric aerosol particles (PM 2.5) and to determine their influence on air quality in Taif city, Saudi Arabia. PM 2.5 particles were collected from two different sites (industrial and residential) in Taif during the summer of 2011. The industrial site was situated in the largest industrial area of Taif, and the residential site was situated in the city's most crowded area. PM 2.5 samples were collected on polycarbonate filters using a cyclonic collector. Each sample was collected over a 24 hour period and new samples were collected weekly. Average PM 2.5 concentrations of 47 ± 15 and 46 ± 31 µg/m 3 were seen in the industrial and residential areas, respectively. An Energy Dispersive X-ray Fluorescence (EDXRF) spectrometer with a Mo secondary target was used to analyze the solid samples because of the relative simplicity of the technique for filter analysis. The use of a Mo secondary target is advantageous, because it decreases the impact of continuum radiation from the X-ray tube and increases the signal to background ratio. Quantitative X-ray Analysis Software (PyMca) was used to perform quantitative analysis of the atmospheric aerosols. The analysis resulted in detected concentrations for sixteen elements; Si,

Low-cost particulate matter (PM) sensors have been under investigation as it has been hypothesized that the use of low-cost and easy-to-use sensors could allow costefficient extension of the currently sparse measurement coverage. While the majority of the existing literature highlights that low-cost sensors can indeed be a valuable addition to the list of commonly used measurement tools, it often reiterates that the risk of sensor misuse is still high and that the data obtained from the sensors are only representative of the specific site and its ambient conditions. This implies that there are underlying reasons for inaccuracies in sensor measurements that have yet to be characterized. The objective of this study is to investigate the particle-size selectivity of lowcost sensors. Evaluated sensors were Plantower PMS5003, Nova SDS011, Sensirion SPS30, Sharp GP2Y1010AU0F, Shinyei PPD42NS, and Omron B5W-LD0101. The investigation of size selectivity was carried out in the laboratory using a novel reference aerosol generation system capable of steadily producing monodisperse particles of different sizes (from ∼ 0.55 to 8.4 µm) on-line. The results of the study show that none of the low-cost sensors adhered to the detection ranges declared by the manufacturers; moreover, cursory comparison to a mid-cost aerosol size spectrometer (Grimm 1.108, 2020) indicates that the sensors can only achieve independent responses for one or two size bins, whereas the spectrometer can sufficiently characterize particles with 15 different size bins. These observations provide insight into and evidence of the notion that particle-size selectivity has an essential role in the analysis of the sources of errors in sensors.

Air pollution in urban environments has been shown to have a negative impact on air quality and human health, particularly in megacities. Over recent decades, Delhi, India, has suffered high atmospheric pollution, with significant particulate matter (PM) concentrations as a result of anthropogenic activities. Organic aerosols (OAs) are composed of thousands of different chemical species and are one of the main constituents of submicron particles. However, quantitative knowledge of OA composition, their sources and their processes in urban environments is still limited. This is important particularly in India, as Delhi is a massive, inhomogeneous conurbation, where we would expect the appor-tionment and concentrations to vary depending on where in Delhi the measurements/source apportionment is performed, indicating the need for multisite measurements. This study presents the first multisite analysis carried out in India over different seasons, with a focus on identifying OA sources. The measurements were taken during 2018 at two sites in Delhi, India. One site was located at the India Meteorological Department, New Delhi (ND). The other site was located at the Indira Gandhi Delhi Technical University for Women, Old Delhi (OD). Non-refractory submicron aerosol (NR-PM 1) concentrations (ammonium, nitrate, sulfate, chloride and organic aerosols) of four aerosol mass spectrometers Published by Copernicus Publications on behalf of the European Geosciences Union. 11656 E. Reyes-Villegas et al.: PM 1 composition and source apportionment at two sites in Delhi were analysed. Collocated measurements of volatile organic compounds, black carbon, NO x and CO were performed. Positive matrix factorisation (PMF) analysis was performed to separate the organic fraction, identifying a number of conventional factors: hydrocarbon-like OAs (HOAs) related to traffic emissions, biomass burning OAs (BBOAs), cooking OAs (COAs) and secondary OAs (SOAs). A composition-based estimate of PM 1 is defined by combining black carbon (BC) and NR-PM 1 (C-PM 1 = BC + NR-PM 1). No significant difference was observed in C-PM 1 concentrations between sites, OD (142 ± 117 µg m −3) compared to ND (123 ± 71 µg m 3), from post-monsoon measurements. A wider variability was observed between seasons, where pre-monsoon and monsoon showed C-PM 1 concentrations lower than 60 µg m −3. A seasonal variation in C-PM 1 composition was observed; SO 2− 4 showed a high contribution over pre-monsoon and monsoon seasons, while NO − 3 and Cl − had a higher contribution in winter and postmonsoon. The main primary aerosol source was from traffic, which is consistent with the PMF analysis and Aethalometer model analysis. Thus, in order to reduce PM 1 concentrations in Delhi through local emission controls, traffic emission control offers the greatest opportunity. PMF-aerosol mass spectrometer (AMS) mass spectra will help to improve future aerosol source apportionment studies. The information generated in this study increases our understanding of PM 1 composition and OA sources in Delhi, India. Furthermore, the scientific findings provide significant information to strengthen legislation that aims to improve air quality in India.

Cultural heritage constitutive materials can provide excellent substrates for microbial colonization, highly influenced by thermo-hygrometric parameters. In cultural heritage-related environments, a detrimental microbial load may be present both on manufacts surface and in the aerosol. In this study, bacterial and fungal colonisation has been investigated in three Sicilian confined environments (archive, cave and hypogea), each with peculiar structures and different thermo-hygrometric parameters. Particular attention has been paid to microorganisms able to induce artifacts biodeterioration and to release biological particles in the aerosol (spores, cellular debrides, toxins and allergens) potentially dangerous for the human health (visitors/users). Results provided information on the composition of the biological consortia, highlighting also the symbiotic relationships between micro (cyanobacteria, bacteria and fungi) and macro-organisms (plants, bryophyte and insects). The results of this integrated approach, including molecular biology techniques, are essential for a complete understanding of both microbial colonization of the cultural objects and the potential relationship with illness to human.

Answer to RC C4048: 'review', Anonymous Referee #2 Dear Referee #2 We thank for your useful comments, corrections and suggestions. We have corrected the text and add a new text and figures according your comments. We hope that our revisions that we have made according your suggestions improve the text of the paper.

The Multi-wavelength Raman LIDAR (MRL) system was developed to enable a better understanding of the complex properties of aerosols in the atmosphere. In this study, the microphysical, optical, and radiative properties of mixed aerosols were retrieved using the discrete aerosol observation products from the MRL. The dust mixing ratio, which is the proportion of dust particles to the total mixed, was derived using the particle depolarization ratio. It was employed in the retrieval of backscattering and extinction coefficient profiles for dust and non-dust particles. The vertical profiles of aerosol optical properties were then used as input parameters in the inversion algorithm for the retrieval of microphysical parameters including the effective radius, refractive index, and the single scattering albedo (SSA). Those products were successfully applied to an analysis of radiative flux using a radiative transfer model. The relationship between the MRL derived extinction and aerosol radiative forcing (ARF) in short-wavelength was assessed over Gwangju, Korea. The results clearly demonstrate that the MRL-derived extinction profiles are a good surrogate for use in the estimation of optical, microphysical, and radiative properties of aerosols. It is considered that the analytical results shown in this study can be used to provide a better understanding of air quality and the variation of local radiative effects due to aerosols.

The vertical distribution of single scattering albedos (SSAs) of Asian dust mixed with pollutants was derived using the multi-wavelength Raman lidar observation system at Gwangju (35.10 • N, 126.53 • E). Vertical profiles of both backscatter and extinction coefficients for dust and non-dust aerosols were extracted from a mixed Asian dust plume using the depolarization ratio from lidar observations. Vertical profiles of backscatter and extinction coefficients of non-dust particles were input into an inversion algorithm to retrieve the SSAs of non-dust aerosols. Atmospheric aerosol layers at different heights had different light-absorbing characteristics. The SSAs of non-dust particles at each height varied with aerosol type, which was either urban/industrial pollutants from China transported over long distances at high altitude, or regional/local pollutants from the Korean peninsula. Taking advantage of independent profiles of SSAs of non-dust particles, vertical profiles of SSAs of Asian dust mixed with pollutants were estimated for the first time, with a new approach suggested in this study using an empirical determination of the SSA of pure dust. The SSAs of the Asian dust-pollutants mixture within the planetary boundary layer (PBL) were in the range 0.88-0.91, while the values above the PBL were in the range 0.76-0.87, with a very low mean value of 0.76 ± 0.05. The total mixed dust plume SSAs in each aerosol layer were integrated over height for comparison with results from the Aerosol Robotics Network (AERONET) measurements. Values of SSA retrieved from lidar observations of 0.92 ± 0.01 were in good agreement with the results from AERONET measurements.

Pr oceed in gs o f t he XXX I I n t ern at io n al Sch oo l o f Sem icond uct i ng Co m p ou n ds, Ja szo wi ec 200 2 Op t i cal P r op ertie s of I n As Q u antu m Dots M . W il l a nd er , Q. X . Z hao , A .P. Ja c ob Ph ysi cal El ect ro ni cs an d Pho to ni cs, D epa rt ment of Physi cs Cha l m ers Uni versi ty of T echnology and G oteb org Uni versi ty 412 9 6 G oteb org, Sweden S.M. W ang and Y .Q. We i D epartm ent of Mi croel ectro ni cs, Pho to ni cs La bora to ry Cha l m ers Uni versi ty of T echnolo gy, 412 96 G oteb org, Sweden InA s quan tu m dots gro w n on GaA s substrat e w ere investigated by optical spectroscopy . W e particula rly emp hasized on the photolumin escence intensity , the stabili ty of the photolumi nescence intensity versus temp eratures and w avelength of the I nA s dot emission at v arious thermal treatments and di ˜erent structures. W e found that hydrogen can strongly passiv ate nonradiative centers w ithout causing any structure degradatio n, and both n -and p -typ e mo dulatio n doping can reduce the decrease in the photolumi nescence intensity w hen the sample temp erature increases from the helium temp erature to ro om temp erature. T he emission wavelength and the e£ciency of the I nA s quantum dots can also be manipul ated by cho osing prop er materials of cap layer.

Resumo Este trabalho possui dois objetivos principais, o primeiro é apresentar uma descrição de como o modelo atmosférico BRAMS foi estruturado com o intuito de capacitá-lo a simular a emissão, dispersão e sedimentação de cinzas vulcânicas; o segundo é fazer uma análise de sensibilidade com relação a diversas configurações do modelo, com o intuito de obter uma configuração adequada para prever a concentração de cinzas vulcânicas após eventos eruptivos. Avaliando os resultados do modelo com dados observados, principalmente com relação ao satélite CALIPSO, concluiu-se que o modelo BRAMS foi capaz de simular e prever com relativa precisão a posição e concentração das cinzas vulcânicas na atmosfera.

Este trabalho possui dois objetivos principais, o primeiro é apresentar uma descrição de como o modelo atmosférico BRAMS foi estruturado com o intuito de capacitá-lo a simular a emissão, dispersão e sedimentação de cinzas vulcânicas; o segundo é fazer uma análise de sensibilidade com relação a diversas configurações do modelo, com o intuito de obter uma configuração adequada para prever a concentração de cinzas vulcânicas após eventos eruptivos. Avaliando os resultados do modelo com dados observados, principalmente com relação ao satélite CALIPSO, concluiu-se que o modelo BRAMS foi capaz de simular e prever com relativa precisão a posição e concentração das cinzas vulcânicas na atmosfera. Palavras chave: modelagem numérica, dispersão de poluentes, vulcões, análise de sensibilidade, métodos numéricos de advecção, cinzas vulcânicas.

Cultural heritage constitutive materials can provide excellent substrates for microbial colonization, highly influenced by thermo-hygrometric parameters. In cultural heritage-related environments, a detrimental microbial load may be present both on manufacts surface and in the aerosol. In this study, bacterial and fungal colonisation has been investigated in three Sicilian confined environments (archive, cave and hypogea), each with peculiar structures and different thermo-hygrometric parameters. Particular attention has been paid to microorganisms able to induce artifacts biodeterioration and to release biological particles in the aerosol (spores, cellular debrides, toxins and allergens) potentially dangerous for the human health (visitors/users). Results provided information on the composition of the biological consortia, highlighting also the symbiotic relationships between micro (cyanobacteria, bacteria and fungi) and macro-organisms (plants, bryophyte and insects). The results of this integrated approach, including molecular biology techniques, are essential for a complete understanding of both microbial colonization of the cultural objects and the potential relationship with illness to human.

Cultural heritage constitutive materials can provide excellent substrates for microbial colonization, highly influenced by thermo-hygrometric parameters. In cultural heritage-related environments, a detrimental microbial load may be present both on manufacts surface and in the aerosol. In this study, bacterial and fungal colonisation has been investigated in three Sicilian confined environments (archive, cave and hypogea), each with peculiar structures and different thermo-hygrometric parameters. Particular attention has been paid to microorganisms able to induce artifacts biodeterioration and to release biological particles in the aerosol (spores, cellular debrides, toxins and allergens) potentially dangerous for the human health (visitors/users). Results provided information on the composition of the biological consortia, highlighting also the symbiotic relationships between micro (cyanobacteria, bacteria and fungi) and macro-organisms (plants, bryophyte and insects). The results ...

Cultural heritage constitutive materials can provide excellent substrates for microbial colonization, highly influenced by thermo-hygrometric parameters. In cultural heritage-related environments, a detrimental microbial load may be present both on manufacts surface and in the aerosol. In this study, bacterial and fungal colonisation has been investigated in three Sicilian confined environments (archive, cave and hypogea), each with peculiar structures and different thermo-hygrometric parameters. Particular attention has been paid to microorganisms able to induce artifacts biodeterioration and to release biological particles in the aerosol (spores, cellular debrides, toxins and allergens) potentially dangerous for the human health (visitors/users). Results provided information on the composition of the biological consortia, highlighting also the symbiotic relationships between micro (cyanobacteria, bacteria and fungi) and macro-organisms (plants, bryophyte and insects). The results of this integrated approach, including molecular biology techniques, are essential for a complete understanding of both microbial colonization of the cultural objects and the potential relationship with illness to human.

Cultural heritage constitutive materials can provide excellent substrates for microbial colonization, highly influenced by thermo-hygrometric parameters. In cultural heritage-related environments, a detrimental microbial load may be present both on manufacts surface and in the aerosol. In this study, bacterial and fungal colonisation has been investigated in three Sicilian confined environments (archive, cave and hypogea), each with peculiar structures and different thermo-hygrometric parameters. Particular attention has been paid to microorganisms able to induce artifacts biodeterioration and to release biological particles in the aerosol (spores, cellular debrides, toxins and allergens) potentially dangerous for the human health (visitors/users). Results provided information on the composition of the biological consortia, highlighting also the symbiotic relationships between micro (cyanobacteria, bacteria and fungi) and macro-organisms (plants, bryophyte and insects). The results ...

Abstract. This study presents the first reference calibrations of three commercially available bioaerosol detectors. The Droplet Measurement Technologies WIBS-NEO, Plair Rapid-E, and Swisens Poleno were compared with a primary standard for particle number concentrations at the Federal Institute for Metrology METAS. Polystyrene (PSL) spheres were used to assess absolute particle counts for diameters from 0.5 μm to 10 μm. For the three devices, counting efficiency was found to be strongly dependent on particle size. The results confirm the expected detection range for which the instruments were designed. While the WIBS-NEO achieves its highest efficiency at smaller particles, e.g. 90 % for 0.9 μm diameter, the Plair Rapid-E performs best for larger particles, with an efficiency of 58 % for particles with a diameter of 10 μm. The Swisens Poleno is also designed for larger particles, but operates well from 2 μm. However, the exact counting efficiency of the Poleno could not be evaluated...

Air pollution in urban environments has been shown to have a negative impact on air quality and human health, particularly in megacities. Over recent decades, Delhi, India, has suffered high atmospheric pollution, with significant particulate matter (PM) concentrations as a result of anthropogenic activities. Organic aerosols (OAs) are composed of thousands of different chemical species and are one of the main constituents of submicron particles. However, quantitative knowledge of OA composition, their sources and their processes in urban environments is still limited. This is important particularly in India, as Delhi is a massive, inhomogeneous conurbation, where we would expect the appor-tionment and concentrations to vary depending on where in Delhi the measurements/source apportionment is performed, indicating the need for multisite measurements. This study presents the first multisite analysis carried out in India over different seasons, with a focus on identifying OA sources. The measurements were taken during 2018 at two sites in Delhi, India. One site was located at the India Meteorological Department, New Delhi (ND). The other site was located at the Indira Gandhi Delhi Technical University for Women, Old Delhi (OD). Non-refractory submicron aerosol (NR-PM 1) concentrations (ammonium, nitrate, sulfate, chloride and organic aerosols) of four aerosol mass spectrometers Published by Copernicus Publications on behalf of the European Geosciences Union. 11656 E. Reyes-Villegas et al.: PM 1 composition and source apportionment at two sites in Delhi were analysed. Collocated measurements of volatile organic compounds, black carbon, NO x and CO were performed. Positive matrix factorisation (PMF) analysis was performed to separate the organic fraction, identifying a number of conventional factors: hydrocarbon-like OAs (HOAs) related to traffic emissions, biomass burning OAs (BBOAs), cooking OAs (COAs) and secondary OAs (SOAs). A composition-based estimate of PM 1 is defined by combining black carbon (BC) and NR-PM 1 (C-PM 1 = BC + NR-PM 1). No significant difference was observed in C-PM 1 concentrations between sites, OD (142 ± 117 µg m −3) compared to ND (123 ± 71 µg m 3), from post-monsoon measurements. A wider variability was observed between seasons, where pre-monsoon and monsoon showed C-PM 1 concentrations lower than 60 µg m −3. A seasonal variation in C-PM 1 composition was observed; SO 2− 4 showed a high contribution over pre-monsoon and monsoon seasons, while NO − 3 and Cl − had a higher contribution in winter and postmonsoon. The main primary aerosol source was from traffic, which is consistent with the PMF analysis and Aethalometer model analysis. Thus, in order to reduce PM 1 concentrations in Delhi through local emission controls, traffic emission control offers the greatest opportunity. PMF-aerosol mass spectrometer (AMS) mass spectra will help to improve future aerosol source apportionment studies. The information generated in this study increases our understanding of PM 1 composition and OA sources in Delhi, India. Furthermore, the scientific findings provide significant information to strengthen legislation that aims to improve air quality in India.