Determining the Role of Acidity, Fate and Formation of IEPOX-Derived SOA in CMAQ

Formation of aerosol from biogenic hydrocarbons relies heavily on anthropogenic emissions since they control the availability of species such as sulfate and nitrate, and through them, aerosol acidity (pH). To elucidate the role that acidity and emissions play in regulating Secondary Organic Aerosol (SOA), we utilize the 2013 Southern Oxidant and Aerosol Study (SOAS) dataset to enhance the extensive mechanism of isoprene epoxydiol (IEPOX)-mediated SOA formation implemented in the Community Multiscale Air Quality (CMAQ) model (Pye et al., 2013), which was then used to investigate the impact of potential future emission controls on IEPOX OA. We found that the Henry’s law coefficient for IEPOX was the most impactful parameter that controls aqueous isoprene OA products, and a value of 1.9 × 107 M atm−1 provides the best agreement with measurements. Non-volatile cations (NVCs) were found in higher-than-expected quantities in CMAQ and exerted a significant influence on IEPOX OA by reducing its production by as much as 30% when present. Consistent with previous literature, a strong correlation of isoprene OA with sulfate, and little correlation with acidity or liquid water content, was found. Future reductions in SO2 emissions are found to not affect this correlation and generally act to increase the sensitivity of IEPOX OA to sulfate, even in extreme cases.

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Examining the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol formation during the 2013 Southern Oxidant and Aerosol Study (SOAS) at the Look Rock, Tennessee ground site

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-8871-2015 ◽

2015 ◽

Vol 15 (15) ◽

pp. 8871-8888 ◽

Cited By ~ 128

Author(s):

S. H. Budisulistiorini ◽

X. Li ◽

S. T. Bairai ◽

J. Renfro ◽

Y. Liu ◽

...

Keyword(s):

Mass Spectrometry ◽

Secondary Organic Aerosol ◽

Organic Aerosol ◽

Anthropogenic Emissions ◽

Strongly Correlated ◽

Particle Phase ◽

Aerosol Formation ◽

Aerosol Acidity ◽

Southeastern Us

Abstract. A suite of offline and real-time gas- and particle-phase measurements was deployed at Look Rock, Tennessee (TN), during the 2013 Southern Oxidant and Aerosol Study (SOAS) to examine the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol (SOA) formation. High- and low-time-resolution PM2.5 samples were collected for analysis of known tracer compounds in isoprene-derived SOA by gas chromatography/electron ionization-mass spectrometry (GC/EI-MS) and ultra performance liquid chromatography/diode array detection-electrospray ionization-high-resolution quadrupole time-of-flight mass spectrometry (UPLC/DAD-ESI-HR-QTOFMS). Source apportionment of the organic aerosol (OA) was determined by positive matrix factorization (PMF) analysis of mass spectrometric data acquired on an Aerodyne Aerosol Chemical Speciation Monitor (ACSM). Campaign average mass concentrations of the sum of quantified isoprene-derived SOA tracers contributed to ~ 9 % (up to 28 %) of the total OA mass, with isoprene-epoxydiol (IEPOX) chemistry accounting for ~ 97 % of the quantified tracers. PMF analysis resolved a factor with a profile similar to the IEPOX-OA factor resolved in an Atlanta study and was therefore designated IEPOX-OA. This factor was strongly correlated (r2 > 0.7) with 2-methyltetrols, C5-alkene triols, IEPOX-derived organosulfates, and dimers of organosulfates, confirming the role of IEPOX chemistry as the source. On average, IEPOX-derived SOA tracer mass was ~ 26 % (up to 49 %) of the IEPOX-OA factor mass, which accounted for 32 % of the total OA. A low-volatility oxygenated organic aerosol (LV-OOA) and an oxidized factor with a profile similar to 91Fac observed in areas where emissions are biogenic-dominated were also resolved by PMF analysis, whereas no primary organic aerosol (POA) sources could be resolved. These findings were consistent with low levels of primary pollutants, such as nitric oxide (NO ~ 0.03 ppb), carbon monoxide (CO ~ 116 ppb), and black carbon (BC ~ 0.2 μg m−3). Particle-phase sulfate is fairly correlated (r2 ~ 0.3) with both methacrylic acid epoxide (MAE)/hydroxymethyl-methyl-α-lactone (HMML)- (henceforth called methacrolein (MACR)-derived SOA tracers) and IEPOX-derived SOA tracers, and more strongly correlated (r2 ~ 0.6) with the IEPOX-OA factor, in sum suggesting an important role of sulfate in isoprene SOA formation. Moderate correlation between the MACR-derived SOA tracer 2-methylglyceric acid with sum of reactive and reservoir nitrogen oxides (NOy; r2 = 0.38) and nitrate (r2 = 0.45) indicates the potential influence of anthropogenic emissions through long-range transport. Despite the lack of a clear association of IEPOX-OA with locally estimated aerosol acidity and liquid water content (LWC), box model calculations of IEPOX uptake using the simpleGAMMA model, accounting for the role of acidity and aerosol water, predicted the abundance of the IEPOX-derived SOA tracers 2-methyltetrols and the corresponding sulfates with good accuracy (r2 ~ 0.5 and ~ 0.7, respectively). The modeling and data combined suggest an anthropogenic influence on isoprene-derived SOA formation through acid-catalyzed heterogeneous chemistry of IEPOX in the southeastern US. However, it appears that this process was not limited by aerosol acidity or LWC at Look Rock during SOAS. Future studies should further explore the extent to which acidity and LWC as well as aerosol viscosity and morphology becomes a limiting factor of IEPOX-derived SOA, and their modulation by anthropogenic emissions.

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Examining the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol formation during the 2013 Southern Oxidant and Aerosol Study (SOAS) at the Look Rock, Tennessee, ground site

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-7365-2015 ◽

2015 ◽

Vol 15 (5) ◽

pp. 7365-7417 ◽

Cited By ~ 7

Author(s):

S. H. Budisulistiorini ◽

X. Li ◽

S. T. Bairai ◽

J. Renfro ◽

Y. Liu ◽

...

Keyword(s):

Mass Spectrometry ◽

Secondary Organic Aerosol ◽

Organic Aerosol ◽

Anthropogenic Emissions ◽

Strongly Correlated ◽

Particle Phase ◽

Aerosol Formation ◽

Aerosol Acidity ◽

Southeastern Us

Abstract. A suite of offline and real-time gas- and particle-phase measurements was deployed at Look Rock, Tennessee (TN), during the 2013 Southern Oxidant and Aerosol Study (SOAS) to examine the effects of anthropogenic emissions on isoprene-derived secondary organic aerosol (SOA) formation. High- and low-time resolution PM2.5 samples were collected for analysis of known tracer compounds in isoprene-derived SOA by gas chromatography/electron ionization-mass spectrometry (GC/EI-MS) and ultra performance liquid chromatography/diode array detection-electrospray ionization-high-resolution quadrupole time-of-flight mass spectrometry (UPLC/DAD-ESI-HR-QTOFMS). Source apportionment of the organic aerosol (OA) was determined by positive matrix factorization (PMF) analysis of mass spectrometric data acquired on an Aerodyne Aerosol Chemical Speciation Monitor (ACSM). Campaign average mass concentrations of the sum of quantified isoprene-derived SOA tracers contributed to ~9% (up to 26%) of the total OA mass, with isoprene-epoxydiol (IEPOX) chemistry accounting for ~97% of the quantified tracers. PMF analysis resolved a factor with a profile similar to the IEPOX-OA factor resolved in an Atlanta study and was therefore designated IEPOX-OA. This factor was strongly correlated (r2>0.7) with 2-methyltetrols, C5-alkene triols, IEPOX-derived organosulfates, and dimers of organosulfates, confirming the role of IEPOX chemistry as the source. On average, IEPOX-derived SOA tracer mass was ~25% (up to 47%) of the IEPOX-OA factor mass, which accounted for 32% of the total OA. A low-volatility oxygenated organic aerosol (LV-OOA) and an oxidized factor with a profile similar to 91Fac observed in areas where emissions are biogenic-dominated were also resolved by PMF analysis, whereas no primary organic aerosol (POA) sources could be resolved. These findings were consistent with low levels of primary pollutants, such as nitric oxide (NO~0.03ppb), carbon monoxide (CO~116 ppb), and black carbon (BC~0.2 μg m−3). Particle-phase sulfate is fairly correlated (r2~0.3) with both MAE- and IEPOX-derived SOA tracers, and more strongly correlated (r2~0.6) with the IEPOX-OA factor, in sum suggesting an important role of sulfate in isoprene SOA formation. Moderate correlation between the methacrylic acid epoxide (MAE)-derived SOA tracer 2-methylglyceric acid with sum of reactive and reservoir nitrogen oxides (NOy; r2=0.38) and nitrate (r2=0.45) indicates the potential influence of anthropogenic emissions through long-range transport. Despite the lack of a~clear association of IEPOX-OA with locally estimated aerosol acidity and liquid water content (LWC), box model calculations of IEPOX uptake using the simpleGAMMA model, accounting for the role of acidity and aerosol water, predicted the abundance of the IEPOX-derived SOA tracers 2-methyltetrols and the corresponding sulfates with good accuracy (r2~0.5 and ~0.7, respectively). The modeling and data combined suggest an anthropogenic influence on isoprene-derived SOA formation through acid-catalyzed heterogeneous chemistry of IEPOX in the southeastern US. However, it appears that this process was not limited by aerosol acidity or LWC at Look Rock during SOAS. Future studies should further explore the extent to which acidity and LWC becomes a limiting factor of IEPOX-derived SOA, and their modulation by anthropogenic emissions.

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Influence of social networks on business processes’ development

Economic Analysis Theory and Practice ◽

10.24891/ea.19.12.2225 ◽

2020 ◽

Vol 19 (12) ◽

pp. 2225-2252

Author(s):

E.V. Popov ◽

V.L. Simonova ◽

O.V. Komarova ◽

S.S. Kaigorodova

Keyword(s):

Social Networks ◽

Social Media ◽

Business Models ◽

Business Processes ◽

Digital Economy ◽

Theoretical Understanding ◽

Sales Channels ◽

A Value ◽

The Impact

Subject. The emergence of new ways of interaction between sellers and buyers, the formation of new sales channels and product promotion based on the use of digital economy tools is at the heart of improving the business processes. Social networks became a tool for development; their rapid growth necessitates theoretical understanding and identification of potential application in enterprise's business process digitalization. Objectives. We explore the role of social media in the digitalization of business processes, systematize the impact of social networks on business processes of enterprises in the digital economy. Methods. The theoretical and methodological analysis of social networks as a tool for digitalization of company's business processes rests on the content analysis of domestic and foreign scientific studies, comparison, generalization and systematization. Results. We highlight the key effects of the impact of social networks on the business processes of the company; show that the digitalization of business processes should be considered in the context of a value-based approach, aimed at creating a value through the algorithmization of company operations. We determine that social networks are one of the most important tools for digitalization of company's business processes, as they have a high organizational and management potential. We also systematize the effects of social media on company's business processes. Conclusions. We present theoretical provisions of the impact of social networks on business processes of enterprises, which will enable to model and organize ideas about the development of digital ecosystems and the formation of business models.

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The stability of onoratoite, Sb8O11Cl2, in the supergene environment

Mineralogical Magazine ◽

10.1180/minmag.2014.078.7.10 ◽

2014 ◽

Vol 78 (7) ◽

pp. 1671-1675 ◽

Cited By ~ 3

Author(s):

Adam J. Roper ◽

Peter Leverett ◽

Timothy D. Murphy ◽

Peter A. Williams

Keyword(s):

Significant Influence ◽

Secondary Phase ◽

Low Ph ◽

Stable Phase ◽

Supergene Zone ◽

A Value ◽

Solubility Studies ◽

The Stability ◽

Very High

AbstractSynthesis and solubility studies of onoratoite have been undertaken to determine the role of this rare secondary phase in the immobilization of Sb and the conditions responsible for its formation in the supergene zone. Solubility studies were undertaken at 298.15 K. A value of ΔGfθ (Sb8O11Cl2, s, 298.15 K) = –2576 ±12 kJ mol–1 was derived. Calculations involving sénarmontite, Sb2O3, klebelsbergite, Sb4O4SO4(OH)2 and schafarzikite, FeSb2O4, show that onoratoite is a thermodynamically stable phase only at negligible activities of SO42–(aq) and low activities of Fe2+(aq), at low pH and very high activities of Cl–(aq). This explains why onoratoite is such a rare secondary phase and why it cannot exert any significant influence on the dispersion of Sb in the supergene environment.

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WUJUD BUDAYA DALAM NOVEL TEGUH ANAK JADAH KARYA A.D. DONGGO (KAJIAN ANTROPOLOGI SASTRA)

EDU-KATA ◽

10.52166/kata.v4i2.1018 ◽

2019 ◽

Vol 5 (2) ◽

pp. 159-168

Author(s):

Amiruddin Amiruddin

Keyword(s):

New Order ◽

Physical Culture ◽

The Novel ◽

Value System ◽

System A ◽

A Value ◽

The Family ◽

Anthropological Literature ◽

The Impact

This research-oriented culture and a form of resistance against the culture of power in the novel Teguh Anak Jadah by A.D. Donggo studied from anthropological literature review. Interdisciplinary between anthropology and literature provide new understanding of the phenomenon of human culture in literature. The method used in this study using hermeneutic methods. This method outlined understand the text and the text intended for a review of literature. Hermeneutical suitable for reading literature for the study of literature, whatever its form, related to an activity that interpretation. In general, the study found a form of culture and a form of resistance against the culture of power in the novel Teguh Anak Jadah by A.D. Donggo. Cultural manifestation in the form of a value system, a system of norms, physical culture, specific rules, politics cultural activities, and the work. Novel Teguh Anak Jadah by A.D. Donggo It also shows the impact of the New Order regime and its cronies make public mindset when it becomes depressed, silent habit deeply ingrained during the New Order government has given rise to a new habit that is easy to forget. Forgetting the role of self, the role of the organization, the role of the family, against fellow citizens of different ideologies.

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Peran Kepala Sekolah Dalam Mengembangkan Mutu Budaya Organisasi

Muslim Heritage ◽

10.21154/muslimheritage.v2i2.1118 ◽

2018 ◽

Vol 2 (2) ◽

pp. 407

Author(s):

ZM Abid Mohammady

Keyword(s):

Organizational Culture ◽

Field Research ◽

Education Institution ◽

Quality Of Education ◽

A Value ◽

Qualitative Descriptive ◽

The Impact

Abstract: In the context of Indonesia, the quality of education seems to be something taboo to talk about, however, according to researchers the quality of education in Indonesia is very apprehensive. It is necessary for the role of headmaster and special efforts in developing a quality education institution through organizational culture as a value system that is understood, imbued, run jointly by members of the organization as a system of meaning or guidance for the organizers. This study aims to describe the three roles and impacts role of the headmaster role in developing the quality of organizational culture, they are: (1) the role of the headmaster as a manager; (2) the role of the headmaster as the educator; (3) the role of the headmaster as the supervisor; 4) The impact of the headmaster's role in developing the quality of organizational culture quality at SDMT Ponorogo. This research is categorized into a field research with qualitative descriptive approach and the research design was case study. The setting of study was at SDMT Ponorogo. The findings showed that (1). The role of headmaster as manager encompasses conducting internal and external analysis, internalizing the Islamic value that is kemuhamadiyahan value. (2). The role of the headmaster as an educator includes involving educators in upgrading, workshops or training in order to provide opportunities for educators to improve their knowledge and skills by learning to the higher education, conducting cadre to members of organizational culture and creating jargon to motivate members of organizational culture. (3). The role of the headmaster as a supervisor comprises overseeing and Evaluating the performance and achievement of members of organizational culture, conducting weekly, monthly and semester meetings, monitoring achievements of educators and learners. (4) The impact of the school headmaster's role in developing the quality of organizational culture is organizational culture climate becomes harmonious and schools achieve more attainments.Abstrak: Dalam konteks Indonesia, mutu pendidikan seolah-olah menjadi barang yang tabu untuk diperbicangkan, dalam konteks tersebut kualitas pendidikan di Indonesia sangat memperihatinkan. Untuk itu diperlukan peran kepala sekolah dan Upaya khusus dalam mengembangkan sebuah mutu lembaga pendidikan melalui budaya organisasi sebagai sistem nilai yang dipahami, dijiwai, dijalankan secara bersama oleh anggota organisasi sebagai sistem makna atau pedoman bagi pelaku organisasi. Penelitian ini bertujuan untuk mendeskripsikan dan menjelaskan tiga peran serta dampak peran kepala sekolah dalam mengembangkan mutu budaya organisasi, yaitu: (1) Peran kepala sekolah sebagai Manajer, (2) Peran kepala sekolah sebagai Educator, (3) Peran kepala sekolah sebagai supervisor, dan (4) Dampak peran kepala sekolah dalam mengembangkan mutu budaya organisasi di SDMT Ponorogo. Dengan menghasilkan temuan: (1).Peran kepala sekolah sebagai manajer diantaranya: melakukan analisis internal dan eksternal, menginternalisasi nilai keislaman yaitu nilai kemuhammadiahan. (2). Peran kepala sekolah sebagai educator diantaranya: mengikut sertakan pendidik dalam penataran, workshop atau pelatihan memberikan kesempatan kepada pendidik untuk meningkatkan pengetahuan dan keterampilannya dengan belajar ke jenjang pendidikan yang lebih tinggi, melakukan pengkaderan kepada anggota budaya organisasi. membuat jargon-jargon untuk memotivasi anggota budaya organisasi. (3). Peran kepala sekolah sebagai supervisor diantarnya: mengawasi dan mengevaluasi kinerja dan pencapaian anggota budaya organisasi, mengadakan rapat setiap, minggu, bulan dan semester, memantau prestasi pendidik dan peserta didik. (4) Dampak peran kepala sekolah dalam mengembangkan mutu budaya organisasi diantaranya: iklim budaya organisasi menjadi harmonis, sekolah menjadi lebih berprestasi.

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Assessing the impact of anthropogenic pollution on isoprene-derived secondary organic aerosol formation in PM<sub>2.5</sub> collected from the Birmingham, Alabama ground site during the 2013 Southern Oxidant and Aerosol Study

10.5194/acp-2015-983 ◽

2016 ◽

Author(s):

W. Rattanavaraha ◽

K. Chu ◽

S. H. Budisulistiorini ◽

M. Riva ◽

Y.-H. Lin ◽

...

Keyword(s):

Mass Spectrometry ◽

Secondary Organic Aerosol ◽

Anthropogenic Pollution ◽

Organic Aerosol ◽

Limiting Factor ◽

Ionization Mass ◽

Aerosol Formation ◽

Anthropogenic Pollutants ◽

Aerosol Acidity ◽

The Impact

Abstract. In the southeastern U.S., substantial emissions of isoprene from deciduous trees undergo atmospheric oxidation to form secondary organic aerosol (SOA) that contributes to fine particulate matter (PM2.5). Laboratory studies have revealed that anthropogenic pollutants, such as sulfur dioxide (SO2), oxides of nitrogen (NOx), and aerosol acidity, can enhance SOA formation from the hydroxyl radical (OH)-initiated oxidation of isoprene; however, the mechanisms by which specific pollutants enhance isoprene SOA in ambient PM2.5 remain unclear. As one aspect of an investigation to examine how anthropogenic pollutants influence isoprene-derived SOA formation, high-volume PM2.5 filter samples were collected at the Birmingham, Alabama (BHM) ground site during the 2013 Southern Oxidant and Aerosol Study (SOAS). Sample extracts were analyzed by gas chromatography/electron ionization-mass spectrometry (GC/EI-MS) with prior trimethylsilylation and ultra performance liquid chromatography coupled to an electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR QTOFMS) to identify known isoprene SOA tracers. Tracers quantified using both surrogate and authentic standards were compared with collocated gas- and particle-phase data as well as meteorological data provided by the Southeastern Aerosol Research and Characterization (SEARCH) network to assess the impact of anthropogenic pollution on isoprene-derived SOA formation. Results of this study reveal that isoprene-derived SOA tracers contribute a substantial mass fraction of organic matter (OM) (~7 to ~20%). Isoprene-derived SOA tracers correlated with sulfate (SO42-) (r2 = 0.34, n = 117), but not with NOx. Moderate correlation between methacrylic acid epoxide and hydroxymethyl-methyl-α-lactone (MAE/HMML)-derived SOA tracers and nitrate radical production (P[NO3]) (r2 = 0.57, n = 40) were observed during nighttime, suggesting a potential role of NO3 radical in forming this SOA type. However, the nighttime correlation of these tracers with nitrogen dioxide (NO2) (r2 = 0.26, n = 40) was weaker. Ozone (O3) correlated strongly with MAE/HMML-derived tracers (r2 = 0.72, n = 30) and moderately with 2-methyltetrols (r2 = 0.34, n = 15) during daytime only, suggesting that a fraction of SOA formation could occur from isoprene ozonolysis in urban areas. No correlation was observed between aerosol pH and isoprene-derived SOA. Lack of correlation between aerosol acidity and isoprene-derived SOA indicates that acidity is not a limiting factor for isoprene SOA formation at the BHM site as aerosols were acidic enough to promote multiphase chemistry of isoprene-derived epoxides throughout the duration of the study. All in all, these results confirm the reports that anthropogenic pollutants enhance isoprene-derived SOA formation.

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The Impact of Celebrity Expertise on Advertising Effectiveness: The Mediating Role of Celebrity Brand Fit

Vision The Journal of Business Perspective ◽

10.1177/0972262917733174 ◽

2017 ◽

Vol 21 (4) ◽

pp. 367-374 ◽

Cited By ~ 5

Author(s):

Tijo Thomas ◽

Johney Johnson

Keyword(s):

Path Analysis ◽

Significant Influence ◽

Purchase Intention ◽

Sampling Method ◽

Advertising Effectiveness ◽

Effectiveness Research ◽

Mediating Role ◽

Area Sampling ◽

The Impact

The studies in the field of marketing have shown that characteristics of the source will influence persuasiveness of the advertisement. This study evaluates the effect of celebrity expertise on advertising effectiveness. Research participants ( N = 109) were selected based on area sampling method. The respondents completed a questionnaire that measured the respondent’s perception of celebrity’s expertise, celebrity brand fit, attitude towards advertisement, attitude towards brand and purchase intention. Path analysis was used to evaluate the hypothesis. The study found that celebrity expertise has got a very significant influence on purchase intention indicating that the practitioner should focus on celebrity’s field of expertise before deciding on the endorsement. The study also found that influence of celebrity brand fit on purchase intention is mediated by the attitude towards advertisement and attitude towards the brand.

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Long-term observational constraints of organic aerosol dependence on inorganic species in the southeast US

10.5194/acp-2020-575 ◽

2020 ◽

Author(s):

Yiqi Zheng ◽

Joel A. Thornton ◽

Nga Lee Ng ◽

Hansen Cao ◽

Daven K. Henze ◽

...

Keyword(s):

Air Quality ◽

Transport Model ◽

Organic Aerosol ◽

Chemical Transport Model ◽

Anthropogenic Pollutants ◽

Aerosol Acidity ◽

Inorganic Species ◽

Southeast Us

Abstract. Organic aerosol (OA), with a large biogenic fraction in summertime southeast US, adversely impacts on air quality and human health. Stringent air quality controls have recently reduced anthropogenic pollutants including sulfate, whose impact on OA remains unclear. Three filter measurement networks provide long-term constraints on the sensitivity of OA to changes in inorganic species, including sulfate and ammonia. The 2000–2013 summertime OA decreases by 1.7~1.9 %/year with little month-to-month variability, while sulfate declines rapidly with significant monthly difference in early 2000s. In contrast, modeled OA from a chemical-transport model (GEOS-Chem) decreases by 4.9 %/year with much larger month-to-month variability, largely due to the predominant role of acid-catalyzed reactive uptake of epoxydiols (IEPOX) onto sulfate. The overestimated modeled OA dependence on sulfate can be improved by implementing a coating effect and assuming constant aerosol acidity, suggesting the needs to revisit IEPOX reactive uptake in current models. Our work highlights the importance of secondary OA formation pathways that are weakly dependent on inorganic aerosol in a region that is heavily influenced by both biogenic and anthropogenic emissions.

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Secondary organic aerosol production from modern diesel engine emissions

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-9-17665-2009 ◽

2009 ◽

Vol 9 (4) ◽

pp. 17665-17704 ◽

Cited By ~ 1

Author(s):

S. Samy ◽

B. Zielinska

Keyword(s):

Secondary Organic Aerosol ◽

Dicarboxylic Acids ◽

Transformation Products ◽

Organic Aerosol ◽

Engine Emissions ◽

No3 Radical ◽

Group Basis ◽

Chamber Studies ◽

The Impact

Abstract. Secondary organic aerosol (SOA) production was observed at significant levels in a series of modern diesel exhaust (DE) aging experiments conducted at the European Outdoor Photoreactor/Simulation Chamber (EUPHORE). The greatest production occurred in DE with toluene addition experiments (>40%), followed by DE with HCHO (for OH radical generation) experiments. A small amount of SOA (3%) was observed for DE in dark with N2O5 (for NO3 radical production) experiments. The analysis for a limited number (54) of polar organic compounds (POC) was conducted to assess the composition of modern DE and the formation of photochemical transformation products. Distinct POC formation in light versus dark experiments suggests the role of OH initiated reactions in these chamber atmospheres. A trend of increasing concentrations of dicarboxylic acids in light versus dark experiments was observed when evaluated on a compound group basis. The four toluene addition experiments in this study were performed at different [tol]o/[NOx]o ratios and displayed an average SOA% yield (in relation to toluene) of 5.3±1.6%, which is compared to past chamber studies that evaluated the impact of [tol]o/[NOx]o on SOA production in more simplified mixtures.

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