A review of experimental techniques for aerosol hygroscopicity studies

Atmospheric chemistry and physics, Journal Year: 2019, Volume and Issue: 19(19), P. 12631 - 12686

Published: Oct. 10, 2019

Abstract. Hygroscopicity is one of the most important physicochemical properties aerosol particles and also plays indispensable roles in many other scientific technical fields. A myriad experimental techniques, which differ principles, configurations cost, are available for investigating hygroscopicity under subsaturated conditions (i.e., relative humidity below 100 %). comprehensive review these techniques provided this paper, broadly classified into four categories, according to way samples investigation prepared. For each technique, we describe its operation principle typical configuration, use representative examples reported previous work illustrate how technique can help better understand hygroscopicity, discuss advantages disadvantages. In addition, future directions outlined discussed further improvement instrumental development.

Language: Английский

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Age-dependent health risk from ambient air pollution: a modelling and data analysis of childhood mortality in middle-income and low-income countries

The Lancet Planetary Health, Journal Year: 2018, Volume and Issue: 2(7), P. e292 - e300

Published: June 29, 2018

BackgroundWHO estimates that, in 2015, nearly 1 million children younger than 5 years died from lower respiratory tract infections (LRIs). Ambient air pollution has a major impact on mortality LRIs, especially combination with undernutrition and inadequate health care. We aimed to estimate due ambient particularly years, investigate what extent exposure this risk factor affects life expectancy different parts of the world.MethodsApplying results recent atmospheric chemistry-general circulation model statistics WHO Global Health Observatory, combined integrated exposure-response functions, we updated our (outdoor) pollution. estimated excess deaths attributable by disease category age group, those pollution-induced LRIs (AAP-LRIs) childhood. Estimates are presented as lost (YLLs). To study developments, calculated for 2010 2015.FindingsOverall, 4·55 (95% CI 3·41 5·56 million) were which 727 000 (573 000–865 000) AAP-LRIs. that AAP-LRIs caused about 237 (192 000–277 child 2015. Although childhood contributed 5% pollution-attributable worldwide, they accounted 18% losses expectancy, equivalent 21·5 (17 25 total 122 YLLs The rate was highest Asia, whereas per capita Africa. sub-Saharan Africa, reduces average 4–5 years. In all-age increased 10% between declined 30% same period.InterpretationMost occur low-income countries Africa Asia. A three-pronged strategy is needed reduce effects children: aggressive reduction levels, improvements nutrition, enhanced treatment pollution-related outcomes.FundingNone.

Language: Английский

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Effects of Atmospheric Processing on the Oxidative Potential of Biomass Burning Organic Aerosols

Environmental Science & Technology, Journal Year: 2019, Volume and Issue: 53(12), P. 6747 - 6756

Published: May 15, 2019

Oxidative potential (OP), which is the ability of certain components in atmospheric particles to generate reactive oxidative species (ROS) and deplete antioxidants vivo, a prevailing toxicological mechanism underlying adverse health effects associated with exposure ambient aerosols. While previous studies have identified high OP fresh biomass burning organic aerosols (BBOA), it remains unclear how evolves throughout transport. Using dithiothreitol (DTT) assay as measure OP, combination field observations laboratory experiments used determine aging transforms intrinsic (OPmassDTT) BBOA. For BBOA collected during fire seasons Greece, OPmassDTT was observed increase by factor 2.1 ± 0.9 for samples ages up 68 h. Laboratory indicate that aqueous photochemical (aging UVB UVA photolysis; well OH oxidation), ozone dilution can transform water-soluble fraction wood smoke within 2 days The results from this work suggest air quality impacts emissions extend beyond regions near sites should be accounted for.

Language: Английский

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Particulate Matter Toxicity Is Nrf2 and Mitochondria Dependent: The Roles of Metals and Polycyclic Aromatic Hydrocarbons

Chemical Research in Toxicology, Journal Year: 2020, Volume and Issue: 33(5), P. 1110 - 1120

Published: April 17, 2020

Particulate matter (PM), an important component of air pollution, induces significant adverse health effects. Many the observed effects caused by inhaled PM are associated with oxidative stress and inflammation. This association has been linked in particular to particles' chemical components, especially inorganic/metal organic/polycyclic aromatic hydrocarbon (PAH) fractions, their ability generate reactive oxygen species biological systems. The transcription factor NF-E2 nuclear erythroid-related 2 (Nrf2) is activated redox imbalance regulates expression phase II detoxifying enzymes. Nrf2 plays a key role preventing PM-induced toxicity protecting against damage review focuses on specific particularly dissolved metals PAH roles inducing inflammation cell animal models respect mitochondria.

Language: Английский

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Exposure of Lung Epithelial Cells to Photochemically Aged Secondary Organic Aerosol Shows Increased Toxic Effects

Environmental Science & Technology Letters, Journal Year: 2018, Volume and Issue: 5(7), P. 424 - 430

Published: June 11, 2018

Adverse health effects due to exposure particulate matter (PM) are among the most important global environmental risks. However, of secondary organic aerosols (SOA), a major component aerosol, largely unknown. Here we exposed lung epithelial cells (A549) fresh and aged SOA particles investigated effect atmospheric aging on cell viability gene expression. Naphthalene- α-pinene-derived were formed in an oxidation flow reactor that simulates formation dominated by OH radical under NOx-free conditions. The mass chemical composition characterized on-line using scanning mobility particle sizer aerosol spectrometer. Fresh directed air–liquid interface system. Aged naphthalene- somewhat more toxic than SOA. naphthalene contained peroxide levels higher those level induction Nrf2 signaling increased following Given prevalence its observed toxicity, this study calls for studies aimed at understanding underlying mechanics.

Language: Английский

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