Measurement of gas-phase OH radical oxidation and film thickness of organic films at the air–water interface using material extracted from urban, remote and wood smoke aerosol

Abstract

The presence of an organic film on a cloud droplet or aqueous aerosol particle has the potential to alter the chemical, optical and physical properties of the droplet or particle.

Exploring the Nanostructures Accessible to an Organic Surfactant Atmospheric Aerosol Proxy

“…Bridging the gap between simple aerosol proxy systems and real atmospheric measurements continues to be a challenge (compare, e.g., Shepherd et al, 2022;Woden et al, 2021). 25,76 However, this study is a step toward linking the laboratory with the real world when considering the relatively novel proposition of LLC phase formation in the atmosphere.…”

Ultraviolet refractive index values of organic aerosol extracted from deciduous forestry, urban and marine environments

“…A thorough description of the sampling and sample extraction procedures can be found in ref. 23 and 45. Prior to trapping, the atmospheric particulate matter extract was transferred to propan-1-ol suitable for ultrasonic nebulisation, similar to ref.…”

“…57,58 In addition, the propensity of organic material to form a film around aerosol particles means that the composition of the organic aerosol fraction is key to determining the climatic impacts of forestry aerosol. 45,58 Forests are responsible for 70% of global biogenic volatile organic compound (BVOC) emissions, 57,59 and between latitudes of 36° N and 68° N, monoterpenes such as α-pinene, β-pinene, and limonene are the dominant BVOC precursors. 58,59 BVOC precursors undergo complex chemical pathways such as in-canopy oxidation and gas-to-particle conversion to form biogenic SOA, 58,60 which comprises 85% of global organic aerosol mass.…”

The evolution of surface structure during simulated atmospheric ageing of nano-scale coatings of an organic surfactant aerosol proxy

“…13 The chemical lifetime of films of insoluble atmospheric organic materials at the air–water interface has been predicted to range from minutes to days with respect to the OH radical. 14 This could have an impact on the residence times of particulate matter, as organic coatings have been shown to prolong the lifetime of pollutants 15 and affect particle water uptake. 16 These observations highlight the importance of understanding how a particle surface film structure responds to atmospheric processing, which we address in this study.…”

“…Neutron and X-ray reectometry (NR and XRR) have been used previously to probe proxy and real organic aerosol materials at the air-water interface. 14,27,[52][53][54][55][56][57][58][59] These surface-sensitive techniques allow for the study of organic lms down to the monolayer level. NR can be particularly sensitive to a sample if it is deuterated, due to the much larger neutron scattering power of a deuterium atom compared with a hydrogen atom.…”