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Airborne particles, specifically nanoparticles, are identified health hazards and a key research domain in air pollution and climate change. We performed a systematic airport study to characterize real-time size and number density distribution, chemical composition and morphology of the aerosols (∼10 nm-10 μm) using complementary cutting-edge and novel techniques, namely optical aerosol analyzers, triple quad ICP-MS/MS and high-resolution STEM imaging. The total number density of aerosols, predominantly composed of nanoparticles, reached a maximum of 2 × 10 6  cm -3 and is higher than reported values from any other international airport. We also provide evidence for a wide range of metal in aerosols, and emerging metals in nanoparticles (e.g., Zn and Ni). The geometric mean, median and 99th and 1st percentile values of observed nanoparticle number densities at the apron were 1.0 × 10 5 , 9.0 × 10 4 , 1.2 × 10 6 and 9.3 × 10 3  cm -3 , respectively. These observations were statistically higher than corresponding measurements in downtown Montreal and at major highways during rush hour. This airport is thus a hotspot for nanoparticles containing emerging contaminants. The diurnal trends in concentrations exhibit peaks during flight and rush hours, showing correlations with pollutants such as CO. The HR-TEM-EDS provided evidence for nano-sized particles produced in combustion engines. Implications of our results for air pollution and health are discussed., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Fossil fuel combustion and many industrial processes generate gaseous emissions that contain a number of toxic organic pollutants and carbon dioxide (CO 2 ) which contribute to climate change and atmospheric pollution. There is a need for green and sustainable solutions to remove air pollutants, as opposed to conventional techniques which can be expensive, consume additional energy and generate further waste. We developed a novel integrated bioreactor combined with recyclable iron oxide nano/micro-particle adsorption interfaces, to remove CO 2, and undesired organic air pollutants using natural particles, while generating oxygen. This semi-continuous bench-scale photo-bioreactor was shown to successfully clean up simulated emission streams of up to 45% CO 2 with a conversion rate of approximately 4% CO 2 per hour, generating a steady supply of oxygen (6mmol/hr), while nanoparticles effectively remove several undesired organic by-products. We also showed algal waste of the bioreactor can be used for mercury remediation. We estimated the potential CO 2 emissions that could be captured from our new method for three industrial cases in which, coal, oil and natural gas were used. With a 30% carbon capture system, the reduction of CO 2 was estimated to decrease by about 420,000, 320,000 and 240,000 metric tonnes, respectively for a typical 500MW power plant. The cost analysis we conducted showed potential to scale-up, and the entire system is recyclable and sustainable. We further discuss the implications of usage of this complete system, or as individual units, that could provide a hybrid option to existing industrial setups., (Copyright © 2016. Published by Elsevier B.V.)

Tropospheric aerosols are involved in several key atmospheric processes: from ice nucleation, cloud formation, and precipitation to weather and climate. The impact of aerosols on these atmospheric processes depends on the chemical and physical characteristics of aerosol particles, and these characteristics are still largely uncertain. In this study, we developed a system for processing and aerosolization of melted snow in particle-free air, coupled with a real-time measurement of aerosol size distributions. The newly developed technique involves bringing snow-borne particles into an airborne state, which enables application of high-resolution aerosol analysis and sampling techniques. This novel analytical approach was compared to a variety of complementary existing analytical methods as applied for characterization of snow samples from remote sites in Alert (Canada) and Barrow (USA), as well as urban Montreal (Canada). The dry aerosol measurements indicated a higher abundance of particles of all sizes, and the 30 nm size dominated in aerosol size distributions for the Montreal samples, closely followed by Barrow, with about 30% fewer 30 nm particles, and about four times lower 30 nm particle abundance in Alert samples, where 15 nm particles were most abundant instead. The aerosolization technique, used together with nanoparticle tracking analysis and electron microscopy, allowed measurement of a wide size range of snow-borne particles in various environmental snow samples. Here, we discuss the application of the new technique to achieve better physicochemical understanding of atmospheric and snow processes. The results showed high sensitivity and reduction of particle aggregation, as well as the ability to measure a high-resolution snow-borne particle size distribution, including nanoparticulate matter in the range of 10 to 100 nm.

Exposure to vehicle exhaust can drive up to 70 % of excess lifetime cancer incidences due to air pollution in urban environments. Little is known about how exhaust-derived particles and organic pollutants, implicated in adverse health effects, are affected by freezing ambient temperatures and the presence of snow. Airborne particles and (semi)volatile organic constituents in dilute exhaust were studied in a novel low-temperature environmental chamber system containing natural urban snow under controlled cold environmental conditions. The presence of snow altered the aerosol size distributions of dilute exhaust in the 10 nm to 10 μm range and decreased the number density of the nanoparticulate (<100 nm) fraction of exhaust aerosols, yet increased the 100-150 nm fraction. Upon 1 hour exhaust exposure, the total organic carbon increased in the natural snow from 0.218 ± 0.014 to 0.539 ± 0.009 mg L(-1), and over 40 additional (semi)volatile organic compounds and a large number of exhaust-derived carbonaceous and likely organic particles were identified. The concentrations of benzene, toluene, ethylbenzene, and xylenes (BTEX) increased from near the detection limit to 52.48, 379.5, 242.7, and 238.1 μg kg(-1) (± 10 %), respectively, indicating the absorption of exhaust-derived toxic organic compounds by snow. The alteration of exhaust aerosol size distributions at freezing temperatures and in the presence of snow, accompanied by changes of the organic pollutant content in snow, has potential to alter health effects of human exposure to vehicle exhaust.