scholarly journals Chemical discrimination of the particulate and gas phases of miniCAST exhausts using a two-filter collection method

Author(s):  
Linh Dan Ngo ◽  
Dumitru Duca ◽  
Yvain Carpentier ◽  
Jennifer A. Noble ◽  
Raouf Ikhenazene ◽  
...  

Abstract. Combustion of hydrocarbons produces both particulate and gas phase emissions responsible for major impacts on atmospheric chemistry and human health. Ascertaining the impact of these emissions, especially on human health, is not straightforward because of our relatively poor knowledge of how chemical compounds are partitioned between the particle and gas phases. Accordingly, we propose to couple a two-filter sampling method with a multi-technique analytical approach to fully characterize the particulate and gas phase compositions of combustion by-products. The two-filter sampling method is designed to retain particulate matter (elemental carbon possibly covered in a surface layer of adsorbed molecules) on a first quartz fiber filter while letting the gas phase pass through, and then trap the most volatile components on a second black carbon-covered filter. All samples thus collected are subsequently subjected to a multi-technique analytical protocol involving two-step laser mass spectrometry (L2MS), secondary ion mass spectrometry (SIMS), and micro-Raman spectroscopy. Using the combination of this two-filter sampling/multi-technique approach in conjunction with advanced statistical methods we are able to unravel distinct surface chemical compositions of aerosols generated with different set points of a miniCAST burner. Specifically, we successfully discriminate samples by their volatile, semi-volatile and non-volatile polycyclic aromatic hydrocarbon (PAH) contents and reveal how subtle changes in combustion parameters affect particle surface chemistry.

2020 ◽  
Vol 13 (2) ◽  
pp. 951-967 ◽  
Author(s):  
Linh Dan Ngo ◽  
Dumitru Duca ◽  
Yvain Carpentier ◽  
Jennifer A. Noble ◽  
Raouf Ikhenazene ◽  
...  

Abstract. Combustion of hydrocarbons produces both particulate- and gas-phase emissions responsible for major impacts on atmospheric chemistry and human health. Ascertaining the impact of these emissions, especially on human health, is not straightforward because of our relatively poor knowledge of how chemical compounds are partitioned between the particle and gas phases. Accordingly, we propose coupling a two-filter sampling method with a multi-technique analytical approach to fully characterize the particulate- and gas-phase compositions of combustion by-products. The two-filter sampling method is designed to retain particulate matter (elemental carbon possibly covered in a surface layer of adsorbed molecules) on a first quartz fiber filter while letting the gas phase pass through and then trap the most volatile components on a second black-carbon-covered filter. All samples thus collected are subsequently subjected to a multi-technique analytical protocol involving two-step laser mass spectrometry (L2MS), secondary ion mass spectrometry (SIMS), and micro-Raman spectroscopy. Using the combination of this two-filter sampling–multi-technique approach in conjunction with advanced statistical methods, we are able to unravel distinct surface chemical compositions of aerosols generated with different set points of a miniCAST burner. Specifically, we successfully discriminate samples by their volatile, semi-volatile, and non-volatile polycyclic aromatic hydrocarbon (PAH) contents and reveal how subtle changes in combustion parameters affect particle surface chemistry.


2021 ◽  
Author(s):  
María Asensio ◽  
María Antiñolo ◽  
Sergio Blázquez ◽  
José Albaladejo ◽  
Elena Jiménez

Abstract. Saturated aldehydes, e.g. 2-methylbutanal (2MB, CH3CH2CH(CH3)C(O)H), are emitted into the atmosphere by several biogenic sources. The first step in the daytime atmospheric degradation of 2MB involves gas-phase reactions initiated by hydroxyl (OH) radicals, chlorine (Cl) atoms and/or sunlight. In this work, we report the rate coefficients for the gas-phase reaction of 2MB with OH (kOH) and Cl (kCl) together with the photolysis rate coefficient (J) in the ultraviolet solar actinic region in Valencia (Spain) at different times of the day. The temperature dependence of kOH was described in the 263–353 K range by the following Arrhenius expression: kOH(T)=(8.88±0.41)×10-12 exp[(331±14)/T] cm3 molecule-1 s-1. At 298 K, the reported kOH and kCl are (2.68±0.07)×10-11 cm3 molecule-1 s-1 and (2.16±0.16)×10-11 cm3 molecule-1 s-1. Identification and quantification of the gaseous products of the Cl-reaction and those from the photodissociation of 2MB were carried out in a smog chamber by different techniques (Fourier transform infrared spectroscopy, proton transfer time-of-flight mass spectrometry, and gas chromatography coupled to mass spectrometry). The formation and size distribution of secondary organic aerosols formed in the Cl-reaction was monitored by a fast mobility particle sizer spectrometer. A discussion on the relative importance of the first step in the daytime atmospheric degradation of 2MB is presented together with the impact of the degradation products in marine atmospheres.


2015 ◽  
Vol 15 (4) ◽  
pp. 2167-2184 ◽  
Author(s):  
S. F. Kong ◽  
L. Li ◽  
X. X. Li ◽  
Y. Yin ◽  
K. Chen ◽  
...  

Abstract. To understand the impact of firework-burning (FW) particles on air quality and human health during the winter haze period, 39 elements, 10 water-soluble ions and 8 fractions of carbonaceous species in atmospheric PM2.5 in Nanjing were investigated during the 2014 Chinese Spring Festival (SF). Serious regional haze pollution persisted throughout the entire sampling period, with PM2.5 averaging at 113 ± 69 μg m−3 and visibility at 4.8 ± 3.2 km. The holiday effect led to almost all the chemical species decreasing during the SF, except for Al, K, Ba and Sr which were related to FW. The source contributions of coal combustion, vehicle emission and road dust decreased dramatically, whereas FW contributed to about half of the PM2.5 during the SF period. The intensive emission of FW particles on New Year's Eve accounted for 60.1% of the PM2.5. Fireworks also obviously modified the chemical compositions of PM2.5, with 39.3% contributed by increased organic matter, followed by steadily increased loadings of secondary inorganic ions. The aging processes of the FW particles lasted for about 4 days reflected by the variations of Ba, Sr, NH4+, NO3−, SO42− and K+, characterized by heterogeneous reactions of SO2 and NOx on crustal materials directly from FW, the replacement of Cl− by NO3− and SO42−, coating of NO3− and SO42− on soot, formation of secondary organic aerosols and metal-catalyzed formation of NO3− and SO42− at higher relative humidity. During aging, the main contributors to the extinction coefficient shifted from elemental carbon and organic matter to ammonium sulfate. The particles raised higher cancer risk of 1.62 × 10−6 by heavy metals (especially for Cd and As). This study provided detailed composition data and first comprehensive analysis of the aging processes of FW particles during the serious haze pollution period and their potential impact on human health.


2014 ◽  
Vol 14 (21) ◽  
pp. 28609-28655 ◽  
Author(s):  
S. Kong ◽  
L. Li ◽  
X. Li ◽  
Y. Yin ◽  
K. Chen ◽  
...  

Abstract. To understand the impact of fireworks burning (FW) particles on air quality and human health during winter haze period, thirty-nine elements, ten water-soluble ions and eight fractions of carbonaceous species in atmospheric PM2.5 at Nanjing were investigated during 2014 Chinese Spring Festival (SF). Serious regional haze pollution persisted throughout the entire sampling period, PM2.5 averaging at 113 ± 69 μg m−3 and visibility at 4.8 ± 3.2 km. The holiday effect led to almost all the chemical species decreasing during the SF, except for Al, K, Ba and Sr which were related to FW. The source contributions of coal combustion, vehicle emission and road dust descreased dramatically, whereas FW contributed to about half of the PM2.5 during SF period. The intensive emission of FW particles at New Year's Eve accounted for 60.1% of the PM2.5. They also significnatly modified the chemical compositions of PM2.5, with 39.3% contributed by increased organic matter, followed by steadly increased loadings of secondary inorganic ions. The aging processes of the FW particles lasted for at least six days reflected by the variation of SO42−, characterized by heterogeneous reactions of SO2 and NOx on crustal materials directly from FW, the replacement of Cl− by NO3− and SO42− coating of NO3− and SO42− on soot, formation of secondary organic aerosols and metal-catalyzed formation of NO3− and SO42− at higher relative humidity. During aging, the main contributors to the extinction coefficient shifted from elemental carbon and organic matter to sulfate ammonium. The particles raised higher cancer risks by heavy metals (especially for Cd and As) as 1.62 ×10−6. This study provided detailed composition data and first comprehensive analysis of the aging processes of FW particles at serious haze pollution period and their potential impact on human health.


Author(s):  
Л.Э. ЧЕМИСОВА ◽  
Н.М. АГЕЕВА ◽  
М.Г. МАРКОВСКИЙ ◽  
Т.И. ГУГУЧКИНА

Исследован ароматический состав водно-спиртовых смывов корковых пробок методом хромато-масс-спектрометрии. Выявлены вещества, которые легко вступают во взаимодействие с компонентами напитка за счет тесного контакта пробки с вином в процессе выдержки и способны оказывать отрицательное влияние на качество и безопасность вин. Установлено наличие летучих веществ синтетического происхождения – гваякола, декалина и его производных, нафталина и его производных, ацетофенона и его производных, 1,3-бензотиазола, триацетина, 2-феноксиэтанола, пропиленгликоля, охрацина, диметилглутарата, являющихся потенциально опасными для здоровья человека. The aromatic composition of water-alcohol washings of cork stoppers was investigated using gas chromatography-mass spectrometry. Substances that easily interact with the components of the drink due to the close contact of the cork with the wine during aging and are able to have a negative impact on the quality and safety of wines are identified. The presence of volatile substances of synthetic origin – guaiacol, decalin and its derivatives, naphthalene and its derivatives, acetophenone and its derivatives, 1,3-benzothiazole, triacetin, 2-phenoxyethanol, propylene glycol, ochracine, dimethylglutarate, which are potentially dangerous to human health, established.


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