Connecting Bulk Viscosity Measurements to Kinetic Limitations on Attaining Equilibrium for a Model Aerosol Composition

Booth, A.; Murphy, Ben; Riipinen, Ilona; Percival, Carl J.; Topping, David

doi:10.1021/es501705c

Cited by 53 publications

(70 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…At this RH, therefore, instantaneous equilibrium partitioning within the particle bulk is not expected to take place. As a result, models that assume equilibrium partitioning at ≤30% RH may over predict SOA particle mass [30,56]. The same would hold true for SOA at different mass loadings, which, as shown above, has an effect on the phase state of α-pinene SOA.…”

Section: α-Pinenementioning

confidence: 86%

The Influence of Absolute Mass Loading of Secondary Organic Aerosols on Their Phase State

2018

View full text Add to dashboard Cite

Absolute secondary organic aerosol (SOA) mass loading (C SOA ) is a key parameter in determining partitioning of semi-and intermediate volatility compounds to the particle phase. Its impact on the phase state of SOA, however, has remained largely unexplored. In this study, systematic laboratory chamber measurements were performed to elucidate the influence of C SOA , ranging from 0.2 to 160 µg m −3 , on the phase state of SOA formed by ozonolysis of various precursors, including α-pinene, limonene, cis-3-hexenyl acetate (CHA) and cis-3-hexen-1-ol (HXL). A previously established method to estimate SOA bounce factor (BF, a surrogate for particle viscosity) was utilized to infer particle viscosity as a function of C SOA . Results show that under nominally identical conditions, the maximum BF decreases by approximately 30% at higher C SOA , suggesting a more liquid phase state. With the exception of HXL-SOA (which acted as the negative control), the phase state for all studied SOA precursors varied as a function of C SOA . Furthermore, the BF was found to be the maximum when SOA particle distributions reached a geometric mean particle diameter of 50-60 nm. Experimental results indicate that C SOA is an important parameter impacting the phase state of SOA, reinforcing recent findings that extrapolation of experiments not conducted at atmospherically relevant SOA levels may not yield results that are relevant to the natural environment.

show abstract

Section: α-Pinenementioning

confidence: 86%

The Influence of Absolute Mass Loading of Secondary Organic Aerosols on Their Phase State

2018

View full text Add to dashboard Cite

show abstract

“…A recent paper has examined the equilibration of water within mixed dicarboxylic acid aerosol particles as a function of viscosity and pointed to the need for more refined descriptions of liquid and glassy phases, and their connection to aerosol properties in laboratory and natural environments. 70 Connection of phase properties to reactivity requires consideration of the aerosol and its environment as a whole, and the computational approach described in this work, shown to apply over a very large range of particle sizes and gas partial pressures, may be helpful in doing so.…”

Section: Discussionmentioning

confidence: 99%

Oxidation of a model alkane aerosol by OH radical: the emergent nature of reactive uptake

Houle

Hinsberg

Wilson

2015

Phys. Chem. Chem. Phys.

155

View full text Add to dashboard Cite

An accurate description of the evolution of organic aerosol in the Earth's atmosphere is essential for climate models. However, the complexity of multiphase chemical and physical transformations has been challenging to describe at the level required to predict aerosol lifetimes and changes in chemical composition. In this work a model is presented that reproduces experimental data for the early stages of oxidative aging of squalane aerosol by hydroxyl radical (OH), a process governed by reactive uptake of gas phase species onto the particle surface. Simulations coupling free radical reactions and Fickian diffusion are used to elucidate how the measured uptake coefficient reflects the elementary steps of sticking of OH to the aerosol as a result of a gas-surface collision, followed by very rapid abstraction of hydrogen and subsequent free radical reactions. It is found that the uptake coefficient is not equivalent to a sticking coefficient or an accommodation coefficient: it is an intrinsically emergent process that depends upon particle size, viscosity, and OH concentration. An expression is derived to examine how these factors control reactive uptake over a broad range of atmospheric and laboratory conditions, and is shown to be consistent with simulation results. Well-mixed, liquid behavior is found to depend on the reaction conditions in addition to the nature of the organic species in the aerosol particle.

show abstract

“…viscosity and diffusivity) and predicted the existence of "glassy" aerosols: particles composed of metastable mixtures of organic compounds, which are highly viscous and show very long timescales for equilibration (including the diffusivity of gaseous oxidants into the particles). Recently, Booth et al (2014) provided experimental data and a thermodynamic description of glassy aerosols composed of simple mixtures of oxygenated organic compounds (dicarboxylic acids). Saukko et al (2012) confirmed the model of Koop et al (2011) with observations of SOA bouncing behaviour in laboratory conditions but also found an effect of molecular composition on the apparent viscosity of the particles (aerosols made up of hydrocarbons behave much less like viscous particles than those composed of oxygenated species).…”

Section: Condensed Phase Of Organic and Inorganic Chemistrymentioning

confidence: 99%

Particulate matter, air quality and climate: lessons learned and future needs

et al. 2015

View full text Add to dashboard Cite

Abstract. The literature on atmospheric particulate matter (PM), or atmospheric aerosol, has increased enormously over the last 2 decades and amounts now to some 1500-2000 papers per year in the refereed literature. This is in part due to the enormous advances in measurement technologies, which have allowed for an increasingly accurate understanding of the chemical composition and of the physical properties of atmospheric particles and of their processes in the atmosphere. The growing scientific interest in atmospheric aerosol particles is due to their high importance for environmental policy. In fact, particulate matter constitutes one of the most challenging problems both for air quality and for climate change policies. In this context, this paper reviews the most recent results within the atmospheric aerosol sciences and the policy needs, which have driven much of the increase in monitoring and mechanistic research over the last 2 decades.The synthesis reveals many new processes and developments in the science underpinning climate-aerosol interactions and effects of PM on human health and the environment. However, while airborne particulate matter is responsible for globally important influences on premature human mortality, we still do not know the relative importance of the different chemical components of PM for these effects. Likewise, the magnitude of the overall effects of PM on climate remains highly uncertain. Despite the uncertainty there are many things that could be done to mitigate local and global problems of atmospheric PM. Recent analyses have shown that reducing black carbon (BC) emissions, using known control measures, would reduce global warming and delay the time when anthropogenic effects on global temperature would exceed 2 • C. Likewise, cost-effective control measures on ammonia, an important agricultural precursor gas for secondary inorganic aerosols (SIA), would reduce regional eutrophication and PM concentrations in large areas of Europe, China and the USA. Thus, there is much that could be done to reduce the effects of atmospheric PM on the climate and the health of the environment and the human population.A prioritized list of actions to mitigate the full range of effects of PM is currently undeliverable due to shortcomings in the knowledge of aerosol science; among the shortcomings, the roles of PM in global climate and the relative roles of Published by Copernicus Publications on behalf of the European Geosciences Union. 8218S. Fuzzi et al.: Particulate matter, air quality and climate different PM precursor sources and their response to climate and land use change over the remaining decades of this century are prominent. In any case, the evidence from this paper strongly advocates for an integrated approach to air quality and climate policies.

show abstract

Connecting Bulk Viscosity Measurements to Kinetic Limitations on Attaining Equilibrium for a Model Aerosol Composition

Cited by 53 publications

References 32 publications

The Influence of Absolute Mass Loading of Secondary Organic Aerosols on Their Phase State

The Influence of Absolute Mass Loading of Secondary Organic Aerosols on Their Phase State

Oxidation of a model alkane aerosol by OH radical: the emergent nature of reactive uptake

Particulate matter, air quality and climate: lessons learned and future needs

Contact Info

Product

Resources

About