Temperature Dependence of Gas–Particle Partitioning of Primary Organic Aerosol Emissions from a Small Diesel Engine

Ranjan, Manish; Presto, Albert A.; May, Andrew A.; Robinson, Allen L.

doi:10.1080/02786826.2011.602761

Cited by 43 publications

(60 citation statements)

References 48 publications

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“…At equilibrium, the volatility of organic species (saturation vapor pressure or, equivalently, saturation concentration, C * ) dictates gas-particle partitioning (Donahue et al, 2006). Enthalpies of vaporization ( H vap ) also influence the change in partitioning with temperature (Epstein et al, 2010;Ranjan et al, 2012). Depending on the volatility of POA and atmospheric perturbations (dilution, changing temperature), semi-volatile species in POA will dynamically partition into gas or particle phases as they move downwind.…”

Section: Introductionmentioning

confidence: 99%

Downwind evolution of the volatility and mixing state of near-road aerosols near a US interstate highway

2018

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Abstract. We present spatial measurements of particle volatility and mixing state at a site near a North Carolina interstate highway (I-40) applying several heating (thermodenuder; TD) experimental approaches. Measurements were conducted in summer 2015 and winter 2016 in a roadside trailer (10 m from road edge) and during downwind transects at different distances from the highway under favorable wind conditions using a mobile platform. Results show that the relative abundance of semi-volatile species (SVOCs) in ultrafine particles decreases with downwind distance, which is consistent with the dilution and mixing of traffic-sourced particles with background air and evaporation of semi-volatile species during downwind transport. An evaporation kinetics model was used to derive particle volatility distributions by fitting TD data. While the TD-derived distribution apportions about 20–30 % of particle mass as semi-volatile (SVOCs; effective saturation concentration, C∗ ≥ 1µm−3) at 10 m from the road edge, approximately 10 % of particle mass is attributed to SVOCs at 220 m, showing that the particle-phase semi-volatile fraction decreases with downwind distance. The relative abundance of semi-volatile material in the particle phase increased during winter. Downwind spatial gradients of the less volatile particle fraction (that remaining after heating at 180 °C) were strongly correlated with black carbon (BC). BC size distribution and mixing state measured using a single-particle soot photometer (SP2) at the roadside trailer showed that a large fraction (70–80 %) of BC particles were externally mixed. Heating experiments with a volatility tandem differential mobility analyzer (V-TDMA) also showed that the nonvolatile fraction in roadside aerosols is mostly externally mixed. V-TDMA measurements at different distances downwind from the highway indicate that the mixing state of roadside aerosols does not change significantly (e.g., BC mostly remains externally mixed) within a few hundred meters from the highway. Our analysis indicates that a superposition of volatility distributions measured in laboratory vehicle tests and of background aerosol can be used to represent the observed partitioning of near-road particles. The results from this study show that exposures and impacts of BC and semi-volatile organics-containing particles in a roadside microenvironment may differ across seasons and under changing ambient conditions.

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Section: Introductionmentioning

confidence: 99%

Downwind evolution of the volatility and mixing state of near-road aerosols near a US interstate highway

2018

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“…γe is often assumed to be in unity in fitting TD data (Grieshop et al, 2009;Li et al, 2016); however, recent 25 studies reported a γe values between 0.01 and 1 for different aerosol systems (Cappa and Jimenez, 2010;Saha et al, 2017b;Saha and Grieshop, 2016;Saleh et al, 2013). Similarly, in literature, different ranges of ΔHvap values are reported for different aerosol systems (Epstein et al, 2010;May et al, 2013c;Ranjan et al, 2012). TD data collected at varying (T, Rt) provides additional constraints on feasible γe and ΔHvap values (Saha et al, 2015(Saha et al, , 2017bSaha and Grieshop, 2016).…”

Section: Parameterizing Volatilitymentioning

confidence: 99%

“…An analysis of temperature effects on the partitioning of semi-volatile materials from vehicular emissions (see Figure S5) indicates that while 40-70% of semi-volatile emissions reside in the particle-phase under typical winter conditions (0-10°C), only 10-20% do so under summer conditions (20-30°C). This analysis used the gasoline POA volatility distribution from May et al (2013a) and ΔHvap from Ranjan et al (2012) and considered a range of OA concentrations for a typical roadside environment (e.g., 0.5 to 5 µg m -3 ). Second, the 10 difference could be due inter-seasonal differences in emission properties (the volatility of what is emitted) and atmospheric dilution.…”

Section: Observed Evaporations In Td With Downwind Distancementioning

confidence: 99%

“…At equilibrium, the volatility of organic 15 species (saturation vapor pressure, or equivalently, saturation concentration, C * ) dictates gas-particle partitioning (Donahue et al, 2006). Enthalpies of vaporization (ΔHvap) also influences the change in partitioning with temperature (Epstein et al, 2010;Ranjan et al, 2012). Depending on the volatility of POA, and atmospheric perturbations (dilution, changing temperature), semi-volatile species in POA will dynamically partition into gas or particle phases as they move downwind.…”

Section: Introductionmentioning

confidence: 99%

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Downwind evolution of the volatility and mixing state of near-road aerosols near a US interstate highway

Saha¹,

Khlystov²,

Grieshop³

2017

Preprint

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Abstract. We present spatial measurements of particle volatility and mixing state at a site near a North Carolina interstate highway (I-40) applying several heating (thermodenuder; TD) experimental approaches. Measurements were conducted in summer 2015 and winter 2016 in a roadside trailer (10 m from road edge) and during downwind transects at different distances 10 from the highway under favorable wind conditions using a mobile platform. Results show that the relative abundance of semivolatile species (SVOCs) in ultrafine particles decreases with downwind distance, consistent with the dilution and mixing of traffic-sourced particles with background air and evaporation of semi-volatile species during downwind transport. An evaporation kinetics model was used to derive particle volatility distributions by fitting TD data. While the TD-derived distribution apportions about 20-30% of particle mass as semi-volatile (SVOCs; effective saturation concentration, C* ≥ 1µ 15 m-3) at 10 m from road edge, approximately 10% of particle mass is attributed to SVOCs at 220 m, showing that the particlephase semi-volatile fraction decreases with downwind distance. The relative abundance of semi-volatile material in the particle-phase increased during winter. Downwind spatial gradients of the less-volatile particle fraction (that remaining after heating at 180°C) was strongly correlated with black carbon (BC). BC size distribution and mixing state measured using a Single Particle Soot Photometer (SP2) at the roadside trailer showed that a large fraction (70-80%) of BC particles were 20 externally-mixed. Heating experiments with a volatility tandem differential mobility analyzer (V-TDMA) also showed that the non-volatile fraction in roadside aerosols are mostly externally mixed. V-TDMA measurements at different distances downwind from the highway indicate that mixing state of roadside aerosols does not change significantly (e.g., BC mostly remains externally mixed) within a few hundred meters from the highway. A preliminary analysis indicates that a superposition of volatility distributions measured in laboratory vehicle tests and of 'background' aerosol can be used to represent 25 the observed partitioning of near-road particles. The results from this study highlight that exposures and impacts of BC and semi-volatile organics containing particles in a near-road microenvironment may differ across seasons and under changing ambient conditions. 30 Atmos. Chem. Phys. Discuss., https://doi

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“…This has been accomplished with dilution samplers , thermodenuders (Huffman et al 2008;Huffman et al 2009), and smog chambers (Grieshop et al 2007;Ranjan et al 2012). The data are then fit into VBS model using absorptive partitioning theory to determine the volatility distribution and particle fractions.…”

Section: Effect Of Temperature Dependence and Dilutionmentioning

confidence: 99%

Estimating ambient particulate organic carbon concentrations and partitioning using thermal optical measurements and the volatility basis set

et al. 2016

Aerosol Science and Technology

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We introduce a new method to estimate the mass concentration of particulate organic carbon (POC) collected on quartz filters, demonstrating it using quartz-filter samples collected in greater Pittsburgh. This method combines thermal-optical organic carbon and elemental carbon (OC/EC) analysis and the volatility basis set (VBS) to quantify the mass concentration of semi-volatile POC on the filters. The dataset includes ambient samples collected at a number of sites in both summer and winter as well as samples from a highway tunnel. As a reference we use the two-filter bare-Quartz minus Quartz-Behind-Teflon (Q-QBT) approach to estimate the adsorbed gaseous fraction of organic carbon (OC), finding a substantial fraction in both the gas and particle phases under all conditions. In the new method we use OC fractions measured during different temperature stages of the OC/EC analysis for the single bare-quartz (BQ) filter in combination with partitioning theory to predict the volatility distributions of the measured OC, which we describe with the VBS. The effective volatility bins are consistent for data from both ambient samples and primary organic aerosol (POA)-enriched tunnel samples. Consequently, with the VBS model and total OC fractions measured over different heating stages, particulate OC can be determined by using the BQ filter alone. This method can thus be applied to all quartz filter-based OC/EC analyses to estimate the POC concentration without using backup filters.

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Temperature Dependence of Gas–Particle Partitioning of Primary Organic Aerosol Emissions from a Small Diesel Engine

Cited by 43 publications

References 48 publications

Downwind evolution of the volatility and mixing state of near-road aerosols near a US interstate highway

Downwind evolution of the volatility and mixing state of near-road aerosols near a US interstate highway

Downwind evolution of the volatility and mixing state of near-road aerosols near a US interstate highway

Estimating ambient particulate organic carbon concentrations and partitioning using thermal optical measurements and the volatility basis set

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