scholarly journals The relative importance of tailpipe and non-tailpipe emissions on the oxidative potential of ambient particles in Los Angeles, CA

2016 ◽  
Vol 189 ◽  
pp. 361-380 ◽  
Author(s):  
Farimah Shirmohammadi ◽  
Sina Hasheminassab ◽  
Dongbin Wang ◽  
James J. Schauer ◽  
Martin M. Shafer ◽  
...  
Keyword(s):  
Los Angeles ◽  
Chemical Constituents ◽  
Univariate Analysis ◽  
Water Soluble ◽  
Crustal Material ◽  
Relative Importance ◽  
Oxidative Potential ◽  
Carbonaceous Species ◽  
Soluble Ions ◽  
Polycyclic Aromatic

This study examines the associations between the oxidative potential of ambient PM2.5and PM0.18, measured by means of the dithiothreitol (DTT) assay, and their chemical constituents and modeled sources. Particulate matter (PM) samples were collected from 2012–2013 in Central Los Angeles (LA) and 2013–2014 in Anaheim, California, USA. Detailed chemical analyses of the PM samples, including carbonaceous species, inorganic elements and water-soluble ions, were conducted. Univariate analysis indicated a high correlation (R> 0.60) between the DTT activity and the concentrations of carbonaceous species at both sites. The strongest correlations were observed between DTT and organic tracers of primary vehicle tailpipe emissions including polycyclic aromatic hydrocarbons (PAHs) and hopanes as well as EC, with higher correlations for PM0.18versusPM2.5components. Moreover, metals and trace elements (e.g., Ba, Cu, Fe, Mn, Pb and Sb) in both size ranges were also associated with DTT activity. Multiple linear regression (MLR) analysis was performed on DTT activity and PM sources identified by a Molecular Marker-Chemical Mass Balance (MM-CMB) model (i.e.major carbonaceous sources: vehicle tailpipe emissions, wood smoke, primary biogenic and secondary organic carbon) together with other typical sources of ambient PM (i.e.crustal material, vehicular abrasion, secondary ions and sea salt). Overall, our findings illustrate the relative importance of different traffic sources on the oxidative potential of ambient PM. Despite major reductions of tailpipe emissions, the lack of similar reductions (and possibly an increase) in non-tailpipe emissions makes them an important source of traffic-related PM in Los Angeles and their increasing role in the overall PM toxicity raises concerns for public health.

scholarly journals Combination of Different Approaches to Infer Local or Regional Contributions to PM2.5 Burdens in Graz, Austria

2020 ◽  
Vol 10 (12) ◽  
pp. 4222
Author(s):  
Bernadette Kirchsteiger ◽  
Magdalena Kistler ◽  
Thomas Steinkogler ◽  
Christopher Herzig ◽  
Andreas Limbeck ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Source Apportionment ◽  
Water Soluble ◽  
The European Union ◽  
Limit Value ◽  
Soluble Ions ◽  
Local Sources ◽  
Polycyclic Aromatic ◽  
Accumulation Of Pollutants ◽  
Short Time

In early 2017 high particulate matter (PM) levels were observed across mid-Europe, including Austria. Here we characterize PM pollution in the city of Graz during January to March 2017, a period with substantial exceedances (34 days) of the European Union (EU) PM10 short time limit value. This study evaluates whether the observed exceedances can be attributed to the accumulation of pollutants emitted by local sources or to a larger scale pollution episode including transport. The analyses are based on the ratios of PM10 concentrations determined at an urban and background site, and the analyses of chemical composition of PM2.5 samples (i.e., water soluble ions, organic and elemental carbon, anhydro-sugars, humic-like substances, aluminum, and polycyclic aromatic hydrocarbons). Source apportionment was realized using a macro-tracer model. Overall, the combination of different approaches (PM10 ratios, chemical composition, and macro-tracer derived source apportionment) enabled a conclusive identification of time periods characterized by the accumulation of emissions from local sources or regional pollution episodes.

scholarly journals Organic aerosol source apportionment by offline-AMS over a full year in Marseille

2017 ◽  
Vol 17 (13) ◽  
pp. 8247-8268 ◽  
Author(s):  
Carlo Bozzetti ◽  
Imad El Haddad ◽  
Dalia Salameh ◽  
Kaspar Rudolf Daellenbach ◽  
Paola Fermo ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Coke Production ◽  
Water Soluble ◽  
Biomass Combustion ◽  
Seasonal Trends ◽  
Soluble Ions ◽  
Yearly Average ◽  
Polycyclic Aromatic ◽  
Field Deployment ◽  
A Minor

Abstract. We investigated the seasonal trends of OA sources affecting the air quality of Marseille (France), which is the largest harbor of the Mediterranean Sea. This was achieved by measurements of nebulized filter extracts using an aerosol mass spectrometer (offline-AMS). In total 216 PM2. 5 (particulate matter with an aerodynamic diameter  <  2.5 µm) filter samples were collected over 1 year from August 2011 to July 2012. These filters were used to create 54 composite samples which were analyzed by offline-AMS. The same samples were also analyzed for major water-soluble ions, metals, elemental and organic carbon (EC ∕ OC), and organic markers, including n-alkanes, hopanes, polycyclic aromatic hydrocarbons (PAHs), lignin and cellulose pyrolysis products, and nitrocatechols. The application of positive matrix factorization (PMF) to the water-soluble AMS spectra enabled the extraction of five factors, related to hydrocarbon-like OA (HOA), cooking OA (COA), biomass burning OA (BBOA), oxygenated OA (OOA), and an industry-related OA (INDOA). Seasonal trends and relative contributions of OA sources were compared with the source apportionment of OA spectra collected from the AMS field deployment at the same station but in different years and for shorter monitoring periods (February 2011 and July 2008). Online- and offline-AMS source apportionment revealed comparable seasonal contribution of the different OA sources. Results revealed that BBOA was the dominant source during winter, representing on average 48 % of the OA, while during summer the main OA component was OOA (63 % of OA mass on average). HOA related to traffic emissions contributed on a yearly average 17 % to the OA mass, while COA was a minor source contributing 4 %. The contribution of INDOA was enhanced during winter (17 % during winter and 11 % during summer), consistent with an increased contribution from light alkanes, light PAHs (fluoranthene, pyrene, phenanthrene), and selenium, which is commonly considered as a unique coal combustion and coke production marker. Online- and offline-AMS source apportionments revealed evolving levoglucosan : BBOA ratios, which were higher during late autumn and March. A similar seasonality was observed in the ratios of cellulose combustion markers to lignin combustion markers, highlighting the contribution from cellulose-rich biomass combustion, possibly related to agricultural activities.

scholarly journals Recognizing Dew as an Indicator and an Improver of Near-Surface Air Quality

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Yingying Xu ◽  
Xinyue Zhu
Keyword(s):  
Air Quality ◽  
Urban Ecosystems ◽  
Water Soluble ◽  
Airborne Particles ◽  
Near Surface ◽  
Carbonaceous Species ◽  
Total Suspended Particulates ◽  
Soluble Ions ◽  
Major Cations ◽  
Water Soluble Ions

The relationship between dew and airborne particles is important in urban ecosystems, but the capability of dew to remove airborne particles remains unclear. During 2015 in Changchun, China, 74 dew and particle samples were collected simultaneously to investigate their chemical characteristics under normal, fog, and haze conditions. Analyses included measuring total dissolved solids, total suspended particulates, PM2.5 and PM10 concentrations, major cations (NH4+, Na+, K+, Ca2+, and Mg2+), major anions (F−, Cl−, SO42-, and NO3-), and organic and elemental carbon. Results showed that air quality deteriorated during haze but improved in fog. The particle size distributions, major cations, and carbonaceous species documented in the dew and airborne particles demonstrated consistent synchronous patterns with values descending in the order haze > normal > fog conditions. We found that dew is a good indicator of near-surface air quality. Specifically, its water-soluble ions and carbonaceous species could be used to distinguish emission sources and to identify the presence of secondary organic carbon. Dew is more effective at removing airborne particles in normal weather than in haze or fog conditions; PM2.5 removal rates were 21.5%, 15.2%, and 13.7% on normal, foggy, and hazy days, respectively. Dew condensation processes reduce concentrations of gaseous and particulate pollutants in the near-surface layer.

Oxidative Potential and Chemical Characteristics of Ambient PM2.5 in Guangzhou, China

2020 ◽  
Author(s):  
Peng Cheng ◽  
Manman Zhang ◽  
Yongjie Li
Keyword(s):  
Consumption Rate ◽  
Dominant Role ◽  
Chemical Species ◽  
Oxidation Potential ◽  
Water Soluble ◽  
Atmospheric Particulate Matter ◽  
Oxidative Potential ◽  
Soluble Ions ◽  
Water Soluble Ions

&lt;p&gt;The dithiothreitol (DTT) assay is widely used to characterize the Oxidation Potential (OP) of atmospheric particulate matter (PM), which can cause adverse effects on human health. However, it&amp;#8217;s under debate which chemical species determines the consumption rate of DTT. During January and April 2018, we measured the improved DTT assay of daily PM&lt;sub&gt;2.5&lt;/sub&gt; samples collected in Guangzhou, China with complimentary measurements of water-soluble ions, organic/elemental carbon (OC/EC) and metal elements. The average sampled air volume normalized consumption rate of DTT (DTT&lt;sub&gt;v&lt;/sub&gt;) was 4.67 &amp;#177;1.06 and 4.45 &amp;#177; 1.02 nmol min&lt;sup&gt;-1&lt;/sup&gt; m&lt;sup&gt;-3&lt;/sup&gt;, in January and April, respectively while the average PM&lt;sub&gt;2.5&lt;/sub&gt; mass normalized consumption rate of DTT (DTT&lt;sub&gt;m&lt;/sub&gt;) was 13.47 &amp;#177; 3.86 and 14.66 &amp;#177; 4.49 pmol min&lt;sup&gt;-1&lt;/sup&gt; &amp;#956;g&lt;sup&gt;-1&lt;/sup&gt;. Good correlations were found between DTT&lt;sub&gt;v&lt;/sub&gt; and concentration of PM&lt;sub&gt;2.5&lt;/sub&gt;, OC, and EC while no correlation was found between DTT&lt;sub&gt;m&lt;/sub&gt; and concentrations of water-soluble ions, OC, EC or metal element, which is consistent with most early observations. We also evaluated the contribution of soluble metals to DTT assay by addition of EDTA, a strong metal chelator. We found that nearly 90% of DTT&lt;sub&gt;v&lt;/sub&gt; and DTT&lt;sub&gt;m&lt;/sub&gt; were reduced by EDTA, suggesting a dominant role of soluble metals in determining the response of DTT to ambient PM&lt;sub&gt;2.5&lt;/sub&gt;. Based on responses of DTT to soluble metals in literature, we found that Cu(II) and Mn(II) are the major contributors to OP of PM&lt;sub&gt;2.5&lt;/sub&gt; in Guangzhou. The correlation coefficient between DTT&lt;sub&gt;m &lt;/sub&gt;and OC shows a clear increase after addition of EDTA, implying that the response of DTT to quinones is not strongly suppressed by EDTA.&lt;/p&gt;

scholarly journals Seasonal Variation and Source Apportionment of Inorganic and Organic Components in PM2.5: Influence of Organic Markers Application on PMF Source Apportionment

2022 ◽  
Author(s):  
Qianqian Xue ◽  
Ying-Ze Tian ◽  
Yang Wei ◽  
Danlin Song ◽  
Fengxia Huang ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Coal Combustion ◽  
Water Soluble ◽  
Secondary Source ◽  
Positive Correlation ◽  
Diesel Vehicles ◽  
Soluble Ions ◽  
Organic Markers ◽  
Polycyclic Aromatic ◽  
Cu And Zn

Abstract PM2.5 samples collected over a 1-year period in a Chinese megacity were analyzed for organic carbon (OC), elemental carbon (EC), water soluble ions, elements and organic markers such as polycyclic aromatic hydrocarbons (PAHs), hopanes, steranes, and n-alkanes. In order to study the applicability of organic markers in source apportionment, this study analyzes the relationship between organic and inorganic components, and four scenarios were implemented by incorporating different combinations of organic and inorganic tracers. A positive correlation of SO42− with 4 rings PAHs can prove that coal burning directly emits a portion of sulfate. A positive correlation of NO3− with 5-7 rings PAHs are found, implying collective impacts from the vehicle source. The concentrations of OC and EC positively correlate with the 5-7 rings PAHs and Cu and Zn, which proves that part of Cu and Zn comes from vehicle emissions. Five factors were identified by incorporating only conventional components, including secondary source (SS, 30%), urban fugitive dust (UFD, 14%), cement dust (CD, 4%), traffic source (TS, 19%) and coal combustion (CC, 14%). Six factors were identified by incorporating conventional components and PAHs, including SS (28%), UFD (15%), CD (4%), CC (13%), gasoline vehicles (GV, 12%) and diesel vehicles (DV, 10%). Eight factors were identified by incorporating conventional components, PAHs, hopanes, and n-alkanes, including SS (26%), UFD (17%), CD (3%), GV (14%), DV (8%), immature coal combustion (ICC, 5%), mature coal combustion (MCC, 10%) and biogenic source (BS, 1%).

scholarly journals Measurement on PM and its chemical compositions for real-world emissions from non-road and on-road diesel vehicles

2016 ◽  
Author(s):  
Min Cui ◽  
Yingjun Chen ◽  
Cheng Li ◽  
Junyu Zheng ◽  
Chongguo Tian ◽  
...  
Keyword(s):  
Real World ◽  
Water Soluble ◽  
Chemical Compositions ◽  
Fuel Quality ◽  
Operating Modes ◽  
Diesel Vehicles ◽  
Emission Standards ◽  
Soluble Ions ◽  
Wide Range ◽  
Polycyclic Aromatic

Abstract. With increasing population of both non-road and on-road diesel vehicles, the adverse effects of PM and its compositions (such as elemental carbon (EC), polycyclic aromatic hydrocarbons (PAHs)) on air quality and human health get more and more attention. However, characteristics of PM and its compositions emitted from diesel vehicles, particularly measured under real-world condition, are scarce. In this study, six excavators and five trucks, involving wide-range emission standards and working in different operating modes, were tested to characterize constituents of PM (including organic carbon (OC), EC, water soluble ions (WSIs), elements, and organic species such as PAHs, n-alkanes, hopanes and steranes). The average emission factors of PM (EFPM) for excavators and trucks were 829 ± 806 and 498 ± 234 mg kg−1 fuel, respectively, which are comparable with other studies. However, EFPM was significantly affected by fuel quality, operating modes and emission standards. High correlation (R2 = 0.79, p 

scholarly journals Chemical Compositions and Source Analysis of PM2.5 during Autumn and Winter in a Heavily Polluted City in China

Atmosphere ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 336
Author(s):  
Shasha Tian ◽  
Yingying Liu ◽  
Jing Wang ◽  
Jian Wang ◽  
Lujian Hou ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Average Concentration ◽  
Water Soluble ◽  
Source Analysis ◽  
Chemical Compositions ◽  
Vehicle Exhaust ◽  
Carbonaceous Species ◽  
Soluble Ions ◽  
Water Soluble Ions ◽  
Heavy Pollution

As one of the biggest cities in North China, Jinan has been suffering heavy air pollution in recent decades. To better characterize the ambient particulate matter in Jinan during heavy pollution periods, we collected daily PM2.5 (particulate matter with aerodynamic diameters equal to or less than 2.5 μm) filter samples from 15 October 2017 to 31 January 2018 and analyzed their chemical compositions (including inorganic water-soluble ions (WSIs), carbonaceous species, and inorganic elements). The daily average concentration of PM2.5 was 83.5 μg/m3 during the sampling period. A meteorological analysis revealed that both low wind speed and high relative humidity facilitated the occurrence of high PM2.5 pollution episodes. A chemical analysis indicated that high concentrations of water-soluble ions, carbonaceous species, and elements were observed during heavy pollution days. The major constituents of PM2.5 in Jinan were secondary aerosol particles and organic matter based on the results of mass closure. Chemical Mass Balance (CMB) was used to track possible sources and identified that nitrate, sulfate, vehicle exhaust and coal fly ash were the main contributors to PM2.5 during heavy pollution days in Jinan, accounting for 25.4%, 18.6%, 18.2%, and 13.3%, respectively.

Measurement of PM2.5 and Water-Soluble Ions at Central Tokyo, Japan and Source Apportionment

2016 ◽  
Vol 2 (2) ◽  
pp. 71-78
Author(s):  
Yoshika Sekine ◽  
◽  
Nami Takahashi ◽  
Yuri Ohkoshi ◽  
Akihiro Takemasa ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Water Soluble ◽  
Soluble Ions ◽  
Water Soluble Ions

scholarly journals Water-Soluble Ions in Atmospheric Aerosol Measured in a Semi-Arid and Chemical-Industrialized City, Northwest China

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 456
Author(s):  
Huimin Jiang ◽  
Zhongqin Li ◽  
Feiteng Wang ◽  
Xi Zhou ◽  
Fanglong Wang ◽  
...  
Keyword(s):  
Sulfur Oxidation ◽  
Northwest China ◽  
Water Soluble ◽  
Heterogeneous Reactions ◽  
Anthropogenic Source ◽  
Heating Period ◽  
Qinghai Province ◽  
Soluble Ions ◽  
Water Soluble Ions ◽  
Semi Arid

We investigated water-soluble ions (WSIs) of aerosol samples collected from 2016 to 2017 in Lanzhou, a typical semi-arid and chemical-industrialized city in Northwest China. WSIs concentration was higher in the heating period (35.68 ± 19.17 μg/m3) and lower in the non-heating period (12.45 ± 4.21 μg/m3). NO3−, SO42−, NH4+ and Ca2+ were dominant WSIs. The concentration of SO42− has decreased in recent years, while the NO3− level was increasing. WSIs concentration was affected by meteorological factors. The sulfur oxidation and nitrogen oxidation ratios (SOR and NOR) exceeded 0.1, inferring the vital contribution of secondary transformation. Meanwhile higher O3 concentration and temperature promoted the homogeneous reaction of SO2. Lower temperature and high relative humidity (RH) were more suitable for heterogeneous reactions of NO2. Three-phase cluster analysis illustrated that the anthropogenic source ions and natural source ions were dominant WSIs during the heating and non-heating periods, respectively. The backward trajectory analysis and the potential source contribution function model indicated that Lanzhou was strongly influenced by the Hexi Corridor, northeastern Qinghai–Tibetan Plateau, northern Qinghai province, Inner Mongolia Plateau and its surrounding cities. This research will improve our understanding of the air quality and pollutant sources in the industrial environment.

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