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

Author(s):  
Peng Cheng ◽  
Manman Zhang ◽  
Yongjie Li

<p>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’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<sub>2.5</sub> 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<sub>v</sub>) was 4.67 ±1.06 and 4.45 ± 1.02 nmol min<sup>-1</sup> m<sup>-3</sup>, in January and April, respectively while the average PM<sub>2.5</sub> mass normalized consumption rate of DTT (DTT<sub>m</sub>) was 13.47 ± 3.86 and 14.66 ± 4.49 pmol min<sup>-1</sup> μg<sup>-1</sup>. Good correlations were found between DTT<sub>v</sub> and concentration of PM<sub>2.5</sub>, OC, and EC while no correlation was found between DTT<sub>m</sub> 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<sub>v</sub> and DTT<sub>m</sub> were reduced by EDTA, suggesting a dominant role of soluble metals in determining the response of DTT to ambient PM<sub>2.5</sub>. 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<sub>2.5</sub> in Guangzhou. The correlation coefficient between DTT<sub>m </sub>and OC shows a clear increase after addition of EDTA, implying that the response of DTT to quinones is not strongly suppressed by EDTA.</p>

2011 ◽  
Vol 324 ◽  
pp. 477-480 ◽  
Author(s):  
Adib Kfoury ◽  
P. Yammine ◽  
Frederic Ledoux ◽  
B. El Khoury ◽  
H. El Nakat ◽  
...  

Atmospheric Total Suspended Particles (TSP) were sampled from 16 different points in a coastal industrial region in North Lebanon, between April and October 2008. The samples were analyzed for water soluble ions and metals concentrations using Ion Chromatography (I.C.) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The results showed possible natural contribution to aerosols through sea salt emissions (Na/Cl-/Mg), and crustal sources (K/Fe/Ti). However, ions such as NH4+, NO3-, and SO42- were attributed to secondary aerosols. Finally, the result of the enrichment factor analysis showed that vehicles’ emissions (Zn/Cu/Pb/Ni/V/Cr), quarries (Ca), and phosphate rocks impurities (Zn/Cd/Cu/Pb) were the most important anthropogenic contributions to the metal’s load in the aerosols.


2022 ◽  
Author(s):  
Jiyan Wu ◽  
Chi Yang ◽  
Chunyan Zhang ◽  
Fang Cao ◽  
Aiping Wu ◽  
...  

Abstract. Excessive reactive oxygen species (ROS) in the human body is an important factor leading to diseases. Therefore, research on the content of reactive oxygen species in atmospheric particles is necessary. In order to more conveniently and accurately detect the content of reactive oxygen in atmospheric particles hour by hour. Here, to modify the instrument, it is added a DTT experimental module that is protected from light and filled with nitrogen at the end, based on the Monitor for AeRosols and Gases in ambient Air (MARGA). The experimental study found that the detection limit of the modified instrument is 0.024 nmol min−1. And the accuracy of the online instrument is determined by comparing the online and offline levels of the samples, which yielded good consistency (slope 0.97, R2 = 0.95). It shows that the performance of the instrument is indeed optimized, the instrument is stable, and the characterization of ROS is accurate. Meanwhile, reactive oxygen and inorganic ions in atmospheric particles are quantified using the online technique in the northern suburbs of Nanjing. It is found that the content of ROS during the day is higher than that at night, especially after it rains, ROS peaks appear in the two time periods of 08:00–10:00 and 16:00–18:00. In addition, examination of the online ROS and water-soluble ions (SO42−, NO3−, NH4+, Na+, Ca2+, K+), BC and polluting gases (SO2, CO, O3, NO, NOx) measurements revealed that photo-oxidation and secondary formation processes could be important sources of aerosol ROS. This method breakthrough enables the quantitative assessment of atmospheric particulate matter ROS at the diurnal scale, providing an effective tool to study sources and environmental impacts of ROS.


2016 ◽  
Vol 2 (2) ◽  
pp. 71-78
Author(s):  
Yoshika Sekine ◽  
◽  
Nami Takahashi ◽  
Yuri Ohkoshi ◽  
Akihiro Takemasa ◽  
...  

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 456
Author(s):  
Huimin Jiang ◽  
Zhongqin Li ◽  
Feiteng Wang ◽  
Xi Zhou ◽  
Fanglong Wang ◽  
...  

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.


2021 ◽  
Vol 102 ◽  
pp. 123-137
Author(s):  
Jie Su ◽  
Pusheng Zhao ◽  
Jing Ding ◽  
Xiang Du ◽  
Youjun Dou

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 926
Author(s):  
Hsing-Wang Li ◽  
Kang-Shin Chen ◽  
Chia-Hsiang Lai ◽  
Ting-Yu Chen ◽  
Yi-Ching Lin ◽  
...  

Atmospheric particulate matters (PMs) were measured in an industry-intensive region in central Taiwan in order to investigate the characteristics and possible sources of PMs. The samplings were simultaneously conducted using a 10- and 3-stage Micro Orifice Uniform Deposit Impactor (MOUDI) from 2017 to 2018. In this study, the characteristics of PMs in this region were evaluated by measuring the mass concentration of PMs and analyzing water-soluble ions and metallic elements, as well as dioxins. Additionally, principal component analysis (PCA) was used to identify the potential sources of PMs. The results showed that the mean concentration of coarse (>1.8 μm), fine (0.1–1.8 μm), and ultrafine (<0.1 μm) particles were 13.60, 14.38, and 3.44 μg/m3, respectively. In the industry-intensive region, the size distribution of ambient particles showed a bi-modal distribution with a high concentration of coarse particles in the spring and summer, while fine particles were dominant in the autumn and winter. The most abundant water-soluble ions of PMs were NO3−, Cl−, and SO42−, while the majority of metallic elements were Na, Fe, Ca, Al, and Mg in different particle sizes. The results of Pearson’s correlation analysis for metals indicated that the particles in the collected air samples were related to the iron and steelmaking industries, coal burning, vehicle exhausts, and high-tech industries. The dioxin concentration ranged from 0.0006 to 0.0017 pg I-TEQ/Nm3. Principal component analysis (PCA) revealed that the contribution to PMs was associated with sea salt, secondary pollutants, and industrial process.


Author(s):  
Shuang Wang ◽  
Mandeep Kaur ◽  
Tengfei Li ◽  
Feng Pan

The present study was planned to explore the pollution characteristics, health risks, and influence of atmospheric fine particulate matter (PM2.5) and its components on blood routine parameters in a typical industrial city (Xinxiang City) in China. In this study, 102 effective samples 28 (April–May), 19 (July–August), 27 (September–October), 28 (December–January) of PM2.5 were collected during different seasons from 2017 to 2018. The water-soluble ions and metal elements in PM2.5 were analyzed via ion chromatography and inductively coupled plasma–mass spectrometry. The blood routine physical examination parameters under different polluted weather conditions from January to December 2017 and 2018, the corresponding PM2.5 concentration, temperature, and relative humidity during the same period were collected from Second People’s Hospital of Xinxiang during 2017–2018. Risk assessment was carried out using the generalized additive time series model (GAM). It was used to analyze the influence of PM2.5 concentration and its components on blood routine indicators of the physical examination population. The “mgcv” package in R.3.5.3 statistical software was used for modeling and analysis and used to perform nonparametric smoothing on meteorological indicators such as temperature and humidity. When Akaike’s information criterion (AIC) value is the smallest, the goodness of fit of the model is the highest. Additionally, the US EPA exposure model was used to evaluate the health risks caused by different heavy metals in PM2.5 to the human body through the respiratory pathway, including carcinogenic risk and non-carcinogenic risk. The result showed that the air particulate matter and its chemical components in Xinxiang City were higher in winter as compared to other seasons with an overall trend of winter > spring > autumn > summer. The content of nitrate (NO3−) and sulfate (SO42−) ions in the atmosphere were higher in winter, which, together with ammonium, constitute the main components of water-soluble ions in PM2.5 in Xinxiang City. Source analysis reported that mobile pollution sources (coal combustion emissions, automobile exhaust emissions, and industrial emissions) in Xinxiang City during the winter season contributed more to atmospheric pollution as compared to fixed sources. The results of the risk assessment showed that the non-carcinogenic health risk of heavy metals in fine particulate matter is acceptable to the human body, while among the carcinogenic elements, the order of lifetime carcinogenic risk is arsenic (As) > chromium(Cr) > cadmium (Cd) > cobalt(Co) > nickel (Ni). During periods of haze pollution, the exposure concentration of PM2.5 has a certain lag effect on blood routine parameters. On the day when haze pollution occurs, when the daily average concentration of PM2.5 rises by 10 μg·m−3, hemoglobin (HGB) and platelet count (PLT) increase, respectively, by 9.923% (95% CI, 8.741–11.264) and 0.068% (95% CI, 0.067–0.069). GAM model analysis predicted the maximum effect of PM2.5 exposure concentration on red blood cell count (RBC) and PLT was reached when the hysteresis accumulates for 1d (Lag0). The maximum effect of exposure concentration ofPM2.5 on MONO is reached when the lag accumulation is 3d (Lag2). When the hysteresis accumulates for 6d (Lag5), the exposure concentration of PM2.5 has the greatest effect on HGB. The maximum cumulative effect of PM2.5 on neutrophil count (NEUT) and lymphocyte (LMY) was strongest when the lag was 2d (Lag1). During periods of moderate to severe pollution, the concentration of water-soluble ions and heavy metal elements in PM2.5 increases significantly and has a significant correlation with some blood routine indicators.


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