scholarly journals Supplementary material to "Seasonal characteristics of organic aerosol chemical composition and volatility in Stuttgart, Germany"

2019 ◽  
Author(s):  
Wei Huang ◽  
Harald Saathoff ◽  
Xiaoli Shen ◽  
Ramakrishna Ramisetty ◽  
Thomas Leisner ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Organic Aerosol ◽  
Seasonal Characteristics ◽  
Supplementary Material ◽  
Aerosol Chemical Composition

scholarly journals Characterization of aerosol chemical composition with aerosol mass spectrometry in Central Europe: an overview

2010 ◽  
Vol 10 (21) ◽  
pp. 10453-10471 ◽  
Author(s):  
V. A. Lanz ◽  
A. S. H. Prévôt ◽  
M. R. Alfarra ◽  
S. Weimer ◽  
C. Mohr ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Chemical Composition ◽  
Organic Aerosol ◽  
Volatile Fraction ◽  
Aerosol Composition ◽  
Aerosol Mass ◽  
Aerosol Mass Spectrometry ◽  
Field Campaigns ◽  
Alpine Valleys ◽  
Aerosol Chemical Composition

Abstract. Real-time measurements of non-refractory submicron aerosols (NR-PM1) were conducted within the greater Alpine region (Switzerland, Germany, Austria, France and Liechtenstein) during several week-long field campaigns in 2002–2009. This region represents one of the most important economic and recreational spaces in Europe. A large variety of sites was covered including urban backgrounds, motorways, rural, remote, and high-alpine stations, and also mobile on-road measurements were performed. Inorganic and organic aerosol (OA) fractions were determined by means of aerosol mass spectrometry (AMS). The data originating from 13 different field campaigns and the combined data have been utilized for providing an improved temporal and spatial data coverage. The average mass concentration of NR-PM1 for the different campaigns typically ranged between 10 and 30 μg m−3. Overall, the organic portion was most abundant, ranging from 36% to 81% of NR-PM1. Other main constituents comprised ammonium (5–15%), nitrate (8–36%), sulfate (3–26%), and chloride (0–5%). These latter anions were, on average, fully neutralized by ammonium. As a major result, time of the year (winter vs. summer) and location of the site (Alpine valleys vs. Plateau) could largely explain the variability in aerosol chemical composition for the different campaigns and were found to be better descriptors for aerosol composition than the type of site (urban, rural etc.). Thus, a reassessment of classifications of measurements sites might be considered in the future, possibly also for other regions of the world. The OA data was further analyzed using positive matrix factorization (PMF) and the multi-linear engine ME (factor analysis) separating the total OA into its underlying components, such as oxygenated (mostly secondary) organic aerosol (OOA), hydrocarbon-like and freshly emitted organic aerosol (HOA), as well as OA from biomass burning (BBOA). OOA was ubiquitous, ranged between 36% and 94% of OA, and could be separated into a low-volatility and a semi-volatile fraction (LV-OOA and SV-OOA) for all summer campaigns at low altitude sites. Wood combustion (BBOA) accounted for a considerable fraction during wintertime (17–49% OA), particularly in narrow Alpine valleys BBOA was often the most abundant OA component. HOA/OA ratios were comparatively low for all campaigns (6–16%) with the exception of on-road, mobile measurements (23%) in the Rhine Valley. The abundance of the aerosol components and the retrievability of SV-OOA and LV-OOA are discussed in the light of atmospheric chemistry and physics.

scholarly journals Effect of NO<sub>x</sub> level on secondary organic aerosol (SOA) formation from the photooxidation of terpenes

2007 ◽  
Vol 7 (19) ◽  
pp. 5159-5174 ◽  
Author(s):  
N. L. Ng ◽  
P. S. Chhabra ◽  
A. W. H. Chan ◽  
J. D. Surratt ◽  
J. H. Kroll ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Organic Nitrates ◽  
Biogenic Hydrocarbons ◽  
Alkoxy Radicals ◽  
Volatile Products ◽  
Products Analysis ◽  
Environmental Chambers ◽  
Aerosol Chemical Composition

Abstract. Secondary organic aerosol (SOA) formation from the photooxidation of one monoterpene (α-pinene) and two sesquiterpenes (longifolene and aromadendrene) is investigated in the Caltech environmental chambers. The effect of NOx on SOA formation for these biogenic hydrocarbons is evaluated by performing photooxidation experiments under varying NOx conditions. The NOx dependence of α-pinene SOA formation follows the same trend as that observed previously for a number of SOA precursors, including isoprene, in which SOA yield (defined as the ratio of the mass of organic aerosol formed to the mass of parent hydrocarbon reacted) decreases as NOx level increases. The NOx dependence of SOA yield for the sesquiterpenes, longifolene and aromadendrene, however, differs from that determined for isoprene and α-pinene; the aerosol yield under high-NOx conditions substantially exceeds that under low-NOx conditions. The reversal of the NOx dependence of SOA formation for the sesquiterpenes is consistent with formation of relatively low-volatility organic nitrates, and/or the isomerization of large alkoxy radicals leading to less volatile products. Analysis of the aerosol chemical composition for longifolene confirms the presence of organic nitrates under high-NOx conditions. Consequently the formation of SOA from certain biogenic hydrocarbons such as sesquiterpenes (and possibly large anthropogenic hydrocarbons as well) may be more efficient in polluted air.

scholarly journals Airborne measurements of the spatial distribution of aerosol chemical composition across Europe and evolution of the organic fraction

2010 ◽  
Vol 10 (8) ◽  
pp. 4065-4083 ◽  
Author(s):  
W. T. Morgan ◽  
J. D. Allan ◽  
K. N. Bower ◽  
E. J. Highwood ◽  
D. Liu ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Chemical Composition ◽  
Ammonium Nitrate ◽  
Western Europe ◽  
Volatile Component ◽  
Organic Aerosol ◽  
Chemical Components ◽  
Airborne Measurements ◽  
North Western ◽  
Aerosol Chemical Composition

Abstract. The spatial distribution of aerosol chemical composition and the evolution of the Organic Aerosol (OA) fraction is investigated based upon airborne measurements of aerosol chemical composition in the planetary boundary layer across Europe. Sub-micron aerosol chemical composition was measured using a compact Time-of-Flight Aerosol Mass Spectrometer (cToF-AMS). A range of sampling conditions were evaluated, including relatively clean background conditions, polluted conditions in North-Western Europe and the near-field to far-field outflow from such conditions. Ammonium nitrate and OA were found to be the dominant chemical components of the sub-micron aerosol burden, with mass fractions ranging from 20–50% each. Ammonium nitrate was found to dominate in North-Western Europe during episodes of high pollution, reflecting the enhanced NOx and ammonia sources in this region. OA was ubiquitous across Europe and concentrations generally exceeded sulphate by 30–160%. A factor analysis of the OA burden was performed in order to probe the evolution across this large range of spatial and temporal scales. Two separate Oxygenated Organic Aerosol (OOA) components were identified; one representing an aged-OOA, termed Low Volatility-OOA and another representing fresher-OOA, termed Semi Volatile-OOA on the basis of their mass spectral similarity to previous studies. The factors derived from different flights were not chemically the same but rather reflect the range of OA composition sampled during a particular flight. Significant chemical processing of the OA was observed downwind of major sources in North-Western Europe, with the LV-OOA component becoming increasingly dominant as the distance from source and photochemical processing increased. The measurements suggest that the aging of OA can be viewed as a continuum, with a progression from a less oxidised, semi-volatile component to a highly oxidised, less-volatile component. Substantial amounts of pollution were observed far downwind of continental Europe, with OA and ammonium nitrate being the major constituents of the sub-micron aerosol burden. Such anthropogenically perturbed air masses can significantly perturb regional climate far downwind of major source regions.

scholarly journals Long-term sub-micrometer aerosol chemical composition in the boreal forest: inter- and intra-annual variability

2020 ◽  
Vol 20 (5) ◽  
pp. 3151-3180 ◽  
Author(s):  
Liine Heikkinen ◽  
Mikko Äijälä ◽  
Matthieu Riva ◽  
Krista Luoma ◽  
Kaspar Dällenbach ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Continuous Monitoring ◽  
Organic Aerosol ◽  
Data Sets ◽  
The Future ◽  
Ca 50 ◽  
Inorganic Aerosol ◽  
Term Data ◽  
Aerosol Chemical Composition

Abstract. The Station for Measuring Ecosystem–Atmosphere Relations (SMEAR) II is well known among atmospheric scientists due to the immense amount of observational data it provides of the Earth–atmosphere interface. Moreover, SMEAR II plays an important role for the large European research infrastructure, enabling the large scientific community to tackle climate- and air-pollution-related questions, utilizing the high-quality long-term data sets recorded at the site. So far, this well-documented site was missing the description of the seasonal variation in aerosol chemical composition, which helps understanding the complex biogeochemical and physical processes governing the forest ecosystem. Here, we report the sub-micrometer aerosol chemical composition and its variability, employing data measured between 2012 and 2018 using an Aerosol Chemical Speciation Monitor (ACSM). We observed a bimodal seasonal trend in the sub-micrometer aerosol concentration culminating in February (2.7, 1.6, and 5.1 µg m−3 for the median, 25th, and 75th percentiles, respectively) and July (4.2, 2.2, and 5.7 µg m−3 for the median, 25th, and 75th percentiles, respectively). The wintertime maximum was linked to an enhanced presence of inorganic aerosol species (ca. 50 %), whereas the summertime maximum (ca. 80 % organics) was linked to biogenic secondary organic aerosol (SOA) formation. During the exceptionally hot months of July of 2014 and 2018, the organic aerosol concentrations were up to 70 % higher than the 7-year July mean. The projected increase in heat wave frequency over Finland will most likely influence the loading and chemical composition of aerosol particles in the future. Our findings suggest strong influence of meteorological conditions such as radiation, ambient temperature, and wind speed and direction on aerosol chemical composition. To our understanding, this is the longest time series reported describing the aerosol chemical composition measured online in the boreal region, but the continuous monitoring will also be maintained in the future.

scholarly journals Measurements of the aerosol chemical composition and mixing state in the Po Valley using multiple spectroscopic techniques

2014 ◽  
Vol 14 (7) ◽  
pp. 9275-9343 ◽  
Author(s):  
S. Decesari ◽  
J. Allan ◽  
C. Plass-Duelmer ◽  
B. J. Williams ◽  
M. Paglione ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Mass Spectrometer ◽  
Time Of Flight ◽  
Organic Aerosol ◽  
Anthropogenic Sources ◽  
Spectroscopic Techniques ◽  
Po Valley ◽  
Aerosol Mass ◽  
On Line ◽  
Aerosol Chemical Composition

Abstract. The use of co-located multiple spectroscopic techniques can provide detailed information on the atmospheric processes regulating aerosol chemical composition and mixing state. So far, field campaigns heavily equipped with aerosol mass spectrometers have been carried out mainly in large conurbations and in areas directly affected by their outflow, whereas lesser efforts have been dedicated to continental areas characterized by a less dense urbanization. We present here the results obtained in San Pietro Capofiume, which is located in a sparsely inhabited sector of the Po Valley, Italy. The experiment was carried out in summer 2009 in the framework of the EUCAARI project ("European Integrated Project on Aerosol, Cloud Climate Aerosol Interaction"). For the first time in Europe, six state-of-the-art techniques were used in parallel: (1) on-line TSI aerosol time-of-flight mass spectrometer (ATOFMS), (2) on-line Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS), (3) soot particle aerosol mass spectrometer (SP-AMS), (4) on-line high resolution time-of-flight mass spectrometer-thermal desorption aerosol gas chromatograph (HR-ToFMS-TAG), (5) off-line twelve-hour resolution proton nuclear magnetic resonance (H-NMR) spectroscopy, and (6) chemical ionization mass spectrometry (CIMS) for the analysis of gas-phase precursors of secondary aerosol. Data from each aerosol spectroscopic method were analysed individually following ad-hoc tools (i.e. PMF for AMS, Art-2a for ATOFMS). The results obtained from each techniques are herein presented and compared. This allows us to clearly link the modifications in aerosol chemical composition to transitions in air mass origin and meteorological regimes. Under stagnant conditions, atmospheric stratification at night and early morning hours led to the accumulation of aerosols produced by anthropogenic sources distributed over the Po Valley plain. Such aerosols include primary components such as black carbon (BC), only partly internally mixed with secondary semivolatile compounds such as ammonium nitrate and amines. Other organic components originating from anthropogenic sources at night include monocarboxylic acids which correspond to an AMS factor analogous to the "cooking" organic aerosol (COA) already identified in urban areas. In daytime, enhanced mixing in the planetary boundary layer (PBL) along with increasing temperature determined dramatic changes in aerosol composition caused by the evaporation of semivolatile components and by the entrainment of aged aerosols transported downwards from residual layers. In other words, the entrainment of aged air masses is responsible for the accumulation of low-volatility oxygenated organic aerosol (LV-OOAs) and also for the recycling of primary species such as black carbon. The LV-OOA concentrations were shown to correlate to the simple meteorological tracers of humid PBL air produced by daytime convection over land areas. In particular, both PMF-AMS and PMF-NMR could resolve two components of LV-OOA: one from long-range transport from Central Europe, the second from recirculated PBL air from the Po Valley. According to organic aerosol source apportionment by PMF-AMS, anthropogenic aerosols accumulating in the lower layers overnight accounted for 38% of organic aerosol mass on average, another 21% was accounted for by aerosols recirculated in residual layers but still originating in North Italy, while a substantial fraction (41%) was due to the most aged aerosols imported from transalpine areas. Overall, the deployment of six state-of-the-art spectrometric techniques provided a comprehensive picture of the nature and source contributions of aerosols and aerosol precursors at a European rural site with unprecedented level of details.

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