scholarly journals Particle Size Distribution Dynamics Can Help Constrain the Phase State of Secondary Organic Aerosol

2021 ◽  
Vol 55 (3) ◽  
pp. 1466-1476
Author(s):  
Yicong He ◽  
Ali Akherati ◽  
Theodora Nah ◽  
Nga L. Ng ◽  
Lauren A. Garofalo ◽  
...  
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Phase State ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Distribution Dynamics

scholarly journals Arctic marine secondary organic aerosol contributes significantly to summertime particle size distributions in the Canadian Arctic Archipelago

2019 ◽  
Vol 19 (5) ◽  
pp. 2787-2812 ◽  
Author(s):  
Betty Croft ◽  
Randall V. Martin ◽  
W. Richard Leaitch ◽  
Julia Burkart ◽  
Rachel Y.-W. Chang ◽  
...  
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Secondary Organic Aerosol ◽  
Canadian Arctic ◽  
Particle Growth ◽  
Organic Aerosol ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
Size Distributions ◽  
Fractional Error

Abstract. Summertime Arctic aerosol size distributions are strongly controlled by natural regional emissions. Within this context, we use a chemical transport model with size-resolved aerosol microphysics (GEOS-Chem-TOMAS) to interpret measurements of aerosol size distributions from the Canadian Arctic Archipelago during the summer of 2016, as part of the “NETwork on Climate and Aerosols: Addressing key uncertainties in Remote Canadian Environments” (NETCARE) project. Our simulations suggest that condensation of secondary organic aerosol (SOA) from precursor vapors emitted in the Arctic and near Arctic marine (ice-free seawater) regions plays a key role in particle growth events that shape the aerosol size distributions observed at Alert (82.5∘ N, 62.3∘ W), Eureka (80.1∘ N, 86.4∘ W), and along a NETCARE ship track within the Archipelago. We refer to this SOA as Arctic marine SOA (AMSOA) to reflect the Arctic marine-based and likely biogenic sources for the precursors of the condensing organic vapors. AMSOA from a simulated flux (500 µgm-2day-1, north of 50∘ N) of precursor vapors (with an assumed yield of unity) reduces the summertime particle size distribution model–observation mean fractional error 2- to 4-fold, relative to a simulation without this AMSOA. Particle growth due to the condensable organic vapor flux contributes strongly (30 %–50 %) to the simulated summertime-mean number of particles with diameters larger than 20 nm in the study region. This growth couples with ternary particle nucleation (sulfuric acid, ammonia, and water vapor) and biogenic sulfate condensation to account for more than 90 % of this simulated particle number, which represents a strong biogenic influence. The simulated fit to summertime size-distribution observations is further improved at Eureka and for the ship track by scaling up the nucleation rate by a factor of 100 to account for other particle precursors such as gas-phase iodine and/or amines and/or fragmenting primary particles that could be missing from our simulations. Additionally, the fits to the observed size distributions and total aerosol number concentrations for particles larger than 4 nm improve with the assumption that the AMSOA contains semi-volatile species: the model–observation mean fractional error is reduced 2- to 3-fold for the Alert and ship track size distributions. AMSOA accounts for about half of the simulated particle surface area and volume distributions in the summertime Canadian Arctic Archipelago, with climate-relevant simulated summertime pan-Arctic-mean top-of-the-atmosphere aerosol direct (−0.04 W m−2) and cloud-albedo indirect (−0.4 W m−2) radiative effects, which due to uncertainties are viewed as an order of magnitude estimate. Future work should focus on further understanding summertime Arctic sources of AMSOA.

scholarly journals Modeling kinetic partitioning of secondary organic aerosol and size distribution dynamics: representing effects of volatility, phase state, and particle-phase reaction

2014 ◽  
Vol 14 (10) ◽  
pp. 5153-5181 ◽  
Author(s):  
R. A. Zaveri ◽  
R. C. Easter ◽  
J. E. Shilling ◽  
J. H. Seinfeld
Keyword(s):  
Size Distribution ◽  
Rate Constant ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Diffusion Reaction ◽  
Aerosol Size Distribution ◽  
Particle Phase ◽  
Distribution Dynamics ◽  
Bulk Diffusivity ◽  
New Framework

Abstract. This paper describes and evaluates a new framework for modeling kinetic gas-particle partitioning of secondary organic aerosol (SOA) that takes into account diffusion and chemical reaction within the particle phase. The framework uses a combination of (a) an analytical quasi-steady-state treatment for the diffusion–reaction process within the particle phase for fast-reacting organic solutes, and (b) a two-film theory approach for slow- and nonreacting solutes. The framework is amenable for use in regional and global atmospheric models, although it currently awaits specification of the various gas- and particle-phase chemistries and the related physicochemical properties that are important for SOA formation. Here, the new framework is implemented in the computationally efficient Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) to investigate the competitive growth dynamics of the Aitken and accumulation mode particles. Results show that the timescale of SOA partitioning and the associated size distribution dynamics depend on the complex interplay between organic solute volatility, particle-phase bulk diffusivity, and particle-phase reactivity (as exemplified by a pseudo-first-order reaction rate constant), each of which can vary over several orders of magnitude. In general, the timescale of SOA partitioning increases with increase in volatility and decrease in bulk diffusivity and rate constant. At the same time, the shape of the aerosol size distribution displays appreciable narrowing with decrease in volatility and bulk diffusivity and increase in rate constant. A proper representation of these physicochemical processes and parameters is needed in the next generation models to reliably predict not only the total SOA mass, but also its composition- and number-diameter distributions, all of which together determine the overall optical and cloud-nucleating properties.

scholarly journals Growth Kinetics and Size Distribution Dynamics of Viscous Secondary Organic Aerosol

2018 ◽  
Vol 52 (3) ◽  
pp. 1191-1199 ◽  
Author(s):  
Rahul A. Zaveri ◽  
John E. Shilling ◽  
Alla Zelenyuk ◽  
Jiumeng Liu ◽  
David M. Bell ◽  
...  
Keyword(s):  
Size Distribution ◽  
Growth Kinetics ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Distribution Dynamics

scholarly journals Arctic marine secondary organic aerosol contributes significantly to summertime particle size distributions in the Canadian Arctic Archipelago

2018 ◽  
Author(s):  
Betty Croft ◽  
Randall V. Martin ◽  
W. Richard Leaitch ◽  
Julia Burkart ◽  
Rachel Y.-W. Chang ◽  
...  
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Secondary Organic Aerosol ◽  
Canadian Arctic ◽  
Particle Growth ◽  
Organic Aerosol ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
Size Distributions ◽  
Fractional Error

Abstract. Summertime Arctic aerosol size distributions are strongly controlled by natural regional emissions. Within this context, we use a chemical transport model with size-resolved aerosol microphysics (GEOS-Chem-TOMAS) to interpret measurements of aerosol size distributions from the Canadian Arctic Archipelago during the summer of 2016, as part of the NETwork on Climate and Aerosols: addressing key uncertainties in Remote Canadian Environments (NETCARE). Our simulations suggest that condensation of secondary organic aerosol (SOA) from precursor vapors emitted in the Arctic and near Arctic marine (open ocean and coastal) regions plays a key role in particle growth events that shape the aerosol size distributions observed at Alert (82.5° N, 62.3° W), Eureka (80.1° N, 86.4° W), and along a NETCARE ship track within the Archipelago. We refer to this SOA as Arctic marine SOA (Arctic MSOA) to reflect the Arctic marine-based and likely biogenic sources for the precursors of the condensing organic vapors. Arctic MSOA from a simulated flux (500 μg m−2 d−1, north of 50° N) of precursor vapors (assumed yield of unity) reduces the summertime particle size distribution model-observation mean fractional error by 2- to 4-fold, relative to a simulation without this Arctic MSOA. Particle growth due to the condensable organic vapor flux contributes strongly (30–50 %) to the simulated summertime-mean number of particles with diameters larger than 20 nm in the study region, and couples with ternary particle nucleation (sulfuric acid, ammonia, and water vapor) and biogenic sulfate condensation to account for more than 90 % of this simulated particle number, a strong biogenic influence. The simulated fit to summertime size-distribution observations is further improved at Eureka and for the ship track by scaling up the nucleation rate by a factor of 100 to account for other particle precursors such as gas-phase iodine and/or amines and/or fragmenting primary particles that could be missing from our simulations. Additionally, the fits to observed size distributions and total aerosol number concentrations for particles larger than 4 nm improve with the assumption that the Arctic MSOA contains semi-volatile species; reducing model-observation mean fractional error by 2- to 3-fold for the Alert and ship track size distributions. Arctic MSOA accounts for more than half of the simulated total particulate organic matter mass concentrations in the summertime Canadian Arctic Archipelago, and this Arctic MSOA has strong simulated summertime pan-Arctic-mean top-of-the-atmosphere aerosol direct (−0.04 W m−2) and cloud-albedo indirect (−0.4 W m−2) radiative effects. Future work should focus on further understanding summertime Arctic sources of Arctic MSOA.

Sign in / Sign up

Export Citation Format

Share Document