Compounds In Fine Particles Research Articles

Variations of aminiums in fine particles at a suburban site in Guangzhou, China: Importance of anthropogenic and natural emissions

Amines are important nitrogen-containing compounds in fine particles (PM2.5) in the atmosphere. Observations are necessary for in-depth understanding on the characteristics, sources and atmospheric processes of aminiums. In this study, the observation of ten C1–C4 aminiums in PM2.5 was conducted in January and March of 2021 in suburban Guangzhou. The concentration and composition of aminiums showed significant differences between the pollution episodes and non-episode periods. Seasonal difference was also observed between winter and spring. The influence of meteorological factors (i.e., wind speed, atmospheric pressure, temperature and relative humidity) was investigated. The variations of aminiums were also affected by different sources. Anthropogenic sources were suggested to be major contributor to aminiums in the pollution episodes, while biological sources were important sources to aminiums in the non-episode periods, especially in spring. Positive matrix factorization receptor model was applied to investigate the source contributions, and four major sources were identified. The results show that vehicular emission, industrial production, biological emission and soil/dust were the major sources of aminiums. This study emphasizes the importance of source contribution and meteorological conditions on the variations of aminiums, which provides further understanding of organic nitrogen in the atmosphere.

Characterization of nitrated aromatic compounds in fine particles from Nanjing, China: Optical properties, source allocation, and secondary processes

Recently, nitrated aromatic compounds (NACs) have received much attention due to their role as key chromophores of brown carbon (BrC) and their impact on human health and the climate. In this study, a method for detection of 12 NACs in the atmosphere was developed and applied to the detection of 191 atmospheric samples in the northern suburbs of Nanjing in 2017. The average concentration of total NACs in Nanjing was 26.48 ng m−3, which was lower than that in North China. The total NACs also showed obvious seasonal variation, with the highest concentration in winter (51.99 ng m−3) and the lowest concentration in summer (11.26 ng m−3). Moreover, the contribution of subcomponents of NACs also changed with the seasons. Nitrophenols (NPs) and nitrocatechols (NCs) were most abundant in winter, while nitrosalicylic acids (NSAs) were more abundant in summer, accounting for 30%, 27%, and 85%, respectively. The reason for this result may be due to the different sources of dominance of NACs in different seasons. The light absorption of NACs to water-soluble BrC was mainly concentrated in the 300–400 nm range, and its contribution reached the maximum at 310 nm. NPs and NCs had the highest contribution to BrC among all NACs in winter, with a range of 25–54% and 3–59%, respectively. The Positive Matrix Factorization (PMF) was used to analyze the main sources of NACs in different seasons. Secondary generation was the largest source in summer, accounting for 43.5%, and biomass combustion contributed the most in autumn, accounting for 36.7%. NACs are affected by temperature, especially in summer, and the subcomponents vary in temperature dependence. The secondary generation process of NACs is affected by NO2 and O3, especially when NO2 is greater than 40 μg m−3 and O3 is less than 220 μg m−3.

Characteristics of Nitroaromatic Compounds in PM2.5 in Urban Area of Shanghai

Nitroaromatic compounds (NACs) are an important class of nitrogen-containing compounds in fine particles. The investigation of characteristics and seasonal variation of NACs in PM2.5 increases our knowledge about nitrogen-containing compounds and contributes to the scientific basis in formulating reduction policies of NOx in urban areas. In this study, we analyzed the chemical composition of PM2.5 samples collected from March 2018 to February 2019 in an urban location in Shanghai. A total of 2439-3695 organic molecular formulas were detected using UPLC-Orbitrap MS. Nine NACs were quantified using an internal standard method. In spring, ρ(NACs) ranged from 3.12 to 16.76 ng·m-3, and the average concentration was 9.31 ng·m-3. In summer, it ranged from 1.05 to 9.70 ng·m-3, and the average value was 4.16 ng·m-3. In autumn, it ranged from 2.87 to 36.27 ng·m-3, and its average was 9.84 ng·m-3. In winter, it ranged from 4.83 to 56.23 ng·m-3, and the average was 22.37 ng·m-3. 4-Nitrophenol accounted for more than 25% of the quantified NACs in different seasons. In summer, the concentration of 5-nitrosalicylic acid accounted for 36%, but it decreased to 19% in winter. NACs in summer mainly originated from secondary formation, as evidenced by their clear correlation with the oxidant level, whereas biomass burning became the main source of NACs in winter.

Characterization of Nitrated Aromatic Compounds in Fine Particles from Nanjing, China: Optical Properties, Source Allocation, and Evolutionary Processes

Characterization of Nitrated Aromatic Compounds in Fine Particles from Nanjing, China: Optical Properties, Source Allocation, and Evolutionary Processes

Characterization of organic aerosols in PM1 and their cytotoxicity in an urban roadside area in Hong Kong

Organic compounds in fine particles play major roles in cardiopulmonary diseases. A study was conducted to determine the characteristics and cytotoxicity of organic aerosols (OA) in an urban roadside area in Hong Kong. Chemical components in nonrefractory submicron aerosol (NR-PM1) were observed using a Quadrupole Aerosol Chemical Speciation Monitor (Q-ACSM), and the chemical profile of organic compounds in NR-PM1 was examined with filter-based approach. Associations between cytotoxicity and organic sources and compositions were evaluated. NR-PM1 contributed to 84% of the PM1 concentrations. The NR-PM1 was composed of organics (55 ± 15%), followed by sulfate (21 ± 9%), ammonium (13 ± 6%), nitrate (10 ± 6%) and chloride (1 ± 1%). Three major organic sources were identified using positive matrix factorization, namely primary organic aerosol (POA, 40 ± 19%), more-oxidized oxygenated OA (MO-OOA, 32 ± 22%) and less-oxidized oxygenated OA (LO-OOA, 28 ± 19%). Variations in organic groups, including alkanes, hopanes, steranes, polycyclic aromatic hydrocarbons (PAHs), oxy-PAHs (OPAHs), and fatty acids, demonstrated that traffic and cooking emissions were dominant pollution sources in this roadside station. Human lung alveolar epithelial (A549) cells were exposed to PM1, revealing increases in lactate dehydrogenase (LDH), reactive oxygen species (ROS), and interlukin-6 (IL-6), which indicated the occurrence of inflammatory and oxidative responses. POA was significantly associated with ROS and IL-6, and alkanes, hopanes, steranes, PAHs and OPAHs, and fatty acids presented medium to high correlations with LDH and IL-6, demonstrating the importance of primary emissions and organic compounds in cytotoxicity. This study demonstrated that organic compounds emitted from traffic and cooking play critical roles in PM-induced oxidative stress and inflammation in urban areas.

Background and fingerprint characteristics of anthropogenic 236U and137Cs in soil and road dust samples collected from Beijing and Zhangjiakou, China

236U has attracted more attention as an environmental tracer in recent years. However, in-depth study of 236U in terrestrial environments is still rare in China. Data on 236U and 137Cs concentrations in soil and road dust samples collected from Beijing and Zhangjiakou, China were obtained to demonstrate the background and distinct characteristics of anthropogenic 236U and 137Cs. 236U and 137Cs were detected in the range of (1.10–7.90) × 107 atoms g−1 and below the method limits of detection to 5.30 Bq kg−1. A clear characteristic was observed in road dust, where 236U concentrations increased with decreasing of sample particle size. Soil samples showed an irregular characteristic, but the highest 236U concentrations were observed in particle size fraction of <0.053 mm in both samples. This phenomenon was caused by U chemical properties, higher specific surface areas and organic compounds in fine particles. Anthropogenic radionuclides fingerprint characteristics in <0.053 mm samples were specially discussed. 236U/238U atom ratios were detected in the range of (0.627–3.38) × 10−8. A weak correlation between anthropogenic 236U and natural U isotopes were observed. The intermediate correlation between 236U and 137Cs indicated somewhat distinct migration behavior of these two radionuclides in soil after release to the environment. The released amount of 236U from global fallout during the period of atmospheric nuclear weapons testing was roughly estimated to be 1300 ± 448 kg. These results could be used as fingerprint information for anthropogenic 236U migration behavior and tracer application in environment.

Molecular characterization of biomass burning tracer compounds in fine particles in Nanjing, China

Abstract In this work, a sensitive method based on the High Performance Liquid Chromatography-Electrospray Ionization-Mass spectrometry/Mass spectrometry (HPLC-ESI-MS/MS) technique was established and validated, and successfully applied to quantify biomass burning tracer species (in total 20 compounds) in fine aerosol particles (PM2.5) collected during the full year of 2016 in Nanjing, China. The annual levoglucosan concentration was determined to be 328.3 ng m−3, at a similar level as it in other Chinese cities; the concentration peaked in fall, indicating influences of crop/straw burning during harvest periods. Concentrations of other species were a few orders of magnitude lower than that of levoglucosan, with salicylic acid (1.53 ng m−3), cis-pinonic acid (0.60 ng m−3) and vanillic acid (0.51 ng m−3) as the three most abundant ones. Total concentrations of tracers indicative of softwood, hardwood and grass burning were about equal. Seasonal concentrations of these tracers were generally similar, and all peaked in winter, different from that of levolglucosan. Further positive matrix factorization (PMF) identified four types of biomass (cellulose, harwood lignin, softwood lignin and grass). Celluose was dominated in fall, while softwood and hardwood were both dominated in winter, and seasonal contributions (except summer) were relatively even to grass. On an annual basis, softwood, hardwood and grass contributions were almost on par to the selected tracers, in agreement with the results based only on concentrations, but seasonally, grass was the major one in spring, summer and fall, but much less important in winter.

An exhaustive classification for the seasonal variation of organic peaks in the atmospheric fine particles obtained by a gas chromatography/mass spectrometry

Abstract For organic compounds in fine particles ( PM 2.5 ), the knowledge on their sources and formation processes are still rather limited because of labile characteristics. To assess the contribution of primary and secondary organic aerosols, it is necessary to utilize the behavior of organic markers. In this study, cluster analysis was applied to the seasonal variations of peaks in chromatogram for unquantitative organic compounds in PM 2.5 obtained by a gas chromatography/mass spectrometry (GC/MS) analysis after derivatization method. We used the PM 2.5 samples collected at Maebashi in Japan for four seasons. Based on cluster analysis, total 115 peaks were divided into nine clusters. The combination effects of the primary and secondary particles transported plume from urban atmosphere were found in two clusters for spring and summer. For dicarboxylic acids, C3 − C5 diacids were in same cluster, whereas C2 and C6 diacids were separated with the other cluster. These results show different trends of secondary formation for dicarboxylic acids. This approach might help to find a group of markers in organic aerosols and to classify potential source of secondary organic aerosols.

Preparation and properties of gadolinium/noble metal fine particle compounds

Preparation and properties of gadolinium/noble metal fine particle compounds

Nonpolar organic compounds in fine particles: quantification by thermal desorption–GC/MS and evidence for their significant oxidation in ambient aerosols in Hong Kong

Nonpolar organic compounds (NPOCs) in ambient particulate matter (PM) commonly include n-alkanes, branched alkanes, hopanes and steranes, and polycyclic aromatic hydrocarbons (PAHs). The recent development of thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) has greatly reduced time and labor in their quantification by eliminating the laborious solvent extraction and sample concentration steps in the traditional approach that relies on solvent extraction. The simplicity of the TD-GCMS methods has afforded us concentration data of NPOCs in more than 90 aerosol samples in two aerosol field studies and 20 vehicular emissions-dominated source samples in Hong Kong over the past few years. In this work, we examine the interspecies relationships between select NPOCs and their concentration ratios to elemental carbon (EC) among the ambient samples and among the source samples. Our analysis indicates that hopanes were mainly from vehicular emissions and they were significantly oxidized in ambient PM. The hopane/EC ratio in ambient samples was on average less than half of the ratio in vehicular emissions-dominated source samples. This highlights the necessity in considering oxidation loss in applying organic tracer data in source apportionment studies. Select PAH/EC ratio-ratio plots reveal that PAHs had diverse sources and vehicular emissions were unlikely a dominant source for PAHs in Hong Kong. Biomass burning and other regional sources likely dominated ambient PAHs in Hong Kong.

Characterization of saccharides and other organic compounds in fine particles and the use of saccharides to track primary biologically derived carbon sources

A total of 134 aerosol samples ( d p < 2.5 μm) were collected at one rural site and one urban site in Texas from November 2005 to July 2006 to investigate the different sources that contribute to the ambient levels of different compounds. In particular, saccharide compounds were studied as potential tracers to track aerosols of biologically derived origin. The ambient concentration, seasonal variation, and urban/rural comparison of major saccharides and other organic compounds including normal alkanes, hopanes, and carboxylic acids were determined and analyzed relative to characterizing sources of PM2.5. Saccharides, together with other known molecular markers, were analyzed by a positive matrix factorization model and eight source factors were isolated that provide meaningful interpretation of aerosol sources. Three isolated factors were characterized by the dominance of different saccharide compounds and were attributed to wood smoke, sucrose rich bio-aerosols, and fungal spore derived bio-aerosols. It was estimated that wood smoke and primary biologically derived carbon sources contributed 22% and 14% to the measured ambient PM2.5 mass at San Augustine and 16% and 5% to the measured ambient PM2.5 mass at Dallas. The relative PM contribution from other resolved sources were also calculated.

Water‐soluble organic nitrogen in atmospheric fine particles (PM2.5) from northern California

Recent studies have suggested that organic nitrogen (ON) is a ubiquitous and significant component of atmospheric dry and wet deposition, but very little is known about the concentrations and speciation of organic nitrogen in aerosol particles. In addition, while amino compounds also appear to be ubiquitous in atmospheric condensed phases, their contribution to organic nitrogen has not been previously quantified. To address these issues, we have characterized the water‐soluble organic nitrogen and amino compounds in fine particles (PM2.5) collected in Davis, California, over a period of 1 year. Concentrations of water‐soluble organic nitrogen (WSON) ranged from 3.1–57.8 nmol N m−3 air, peaking during winter and early spring, and typically accounted for ∼20% of total nitrogen in Davis PM2.5. Assuming an average N‐normalized molecular weight of 100 Da per N atom for WSON, particulate organic nitrogen had a median mass concentration of 1.6 μg m−3 air, and typically represented 18% of the total fine particle mass. The average mass of water‐soluble ON in Davis PM2.5 was comparable to that of sulfate during the summer, but was significantly higher in winter. Total amino compounds (free plus combined forms) made up a significant portion of particulate organic nitrogen (median value equal to 23%), primarily due to the presence of combined amino compounds such as proteins and peptides. Total amino compounds had a median mass concentration of 290 ng m−3 air, and typically accounted for 3.3% of the total fine particle mass. These results indicate that organic nitrogen is a significant component of fine particles in northern California, and suggest that this group of compounds might play an important role in the ecological, radiative, and potential health effects of atmospheric fine particles in this region.

Determination of the Size Distribution and Chemical Composition of Fine Particulate Semivolatile Organic Material in Urban Environments Using Diffusion Denuder Technology

AbstractCollection of particles on a filter results in underestimation of particulate organic compounds due to losses from the semivolatile organic fraction during sample collection, that is, a “negative sampling artifact.” This sampling-induced change in the phase distribution of semivolatile organic material resulted in the loss of an average of 35% of the particulate organic material in samples collected at the South Coast Air Quality Management District (SCAQMD) sampling site at Azusa, CA, in the Los Angeles Basin. These semivolatile organic compounds lost from particles were measured using two diffusion denuder sampling systems. A multichannel diffusion denuder sampling system (BOSS) was used to determine the concentrations of fine particulate carbonaceous material, and a multisystem, multichannel, high-volume diffusion denuder sampler (BIG BOSS) was used for the determination of the particle size distribution and chemical composition of semivolatile organic compounds in fine particles. Results obtai...