Sources of Cellular Oxidative Potential of Water-soluble Fine Ambient Particulate Matter in the Midwestern United States

2021 ◽  
pp. 127777
Author(s):  
Yixiang Wang ◽  
Joseph V Puthussery ◽  
Haoran Yu ◽  
Yicen Liu ◽  
Sudheer Salana ◽  
...  
Keyword(s):  
United States ◽  
Particulate Matter ◽  
Water Soluble ◽  
Ambient Particulate Matter ◽  
Oxidative Potential ◽  
Midwestern United States

scholarly journals Spatiotemporal variability in the oxidative potential of ambient fine particulate matter in the Midwestern United States

2021 ◽  
Vol 21 (21) ◽  
pp. 16363-16386
Author(s):  
Haoran Yu ◽  
Joseph Varghese Puthussery ◽  
Yixiang Wang ◽  
Vishal Verma
Keyword(s):  
United States ◽  
Particulate Matter ◽  
Fine Particulate Matter ◽  
Water Soluble ◽  
Spatiotemporal Variability ◽  
Large Set ◽  
Oxidative Potential ◽  
Midwestern United States ◽  
Spatiotemporal Trends ◽  
Fine Particulate

Abstract. We assessed the oxidative potential (OP) of both water-soluble and methanol-soluble fractions of ambient fine particulate matter (PM2.5) in the Midwestern United States. A large set of PM2.5 samples (N=241) was collected from five sites set up in different environments, i.e., urban, rural, and roadside, in Illinois, Indiana, and Missouri during May 2018–May 2019. Five acellular OP endpoints, including the consumption rate of ascorbic acid and glutathione in a surrogate lung fluid (SLF) (OPAA and OPGSH, respectively), dithiothreitol (DTT) depletion rate (OPDTT), and ⚫OH generation rate in SLF and DTT (OPOH−SLF and OPOH−DTT, respectively), were measured for all PM2.5 samples. PM2.5 mass concentrations in the Midwestern US as obtained from these samples were spatially homogeneously distributed, while most OP endpoints showed significant spatiotemporal heterogeneity. Seasonally, higher activities occurred in summer for most OP endpoints for both water- and methanol-soluble extracts. Spatially, the roadside site showed the highest activities for most OP endpoints in the water-soluble extracts, while only occasional peaks were observed at urban sites in the methanol-soluble OP. Most OP endpoints showed similar spatiotemporal trends between mass- and volume-normalized activities across different sites and seasons. Comparisons between two solvents (i.e., water and methanol) showed that methanol-soluble OP generally had higher activity levels than corresponding water-soluble OP. Site-to-site comparisons of OP showed stronger correlations for methanol-soluble OP compared to water-soluble OP, indicating a better extraction of water-insoluble redox-active compounds from various emission sources into methanol. We found a weak correlation and inconsistent slope values between PM2.5 mass and most OP endpoints. Moreover, the poor to moderate intercorrelations among different OP endpoints indicate different mechanisms of OP represented by these endpoints and thus demonstrate the rationale for analyzing multiple acellular endpoints for a better and more comprehensive assessment of OP.

scholarly journals Spatiotemporal Variability in the Oxidative Potential of Ambient Fine Particulate Matter in Midwestern United States

2021 ◽  
Author(s):  
Haoran Yu ◽  
Joseph Varghese Puthussery ◽  
Yixiang Wang ◽  
Vishal Verma
Keyword(s):  
United States ◽  
Particulate Matter ◽  
Fine Particulate Matter ◽  
Water Soluble ◽  
Spatiotemporal Variability ◽  
Large Set ◽  
Oxidative Potential ◽  
Midwestern United States ◽  
Spatiotemporal Trends ◽  
Fine Particulate

Abstract. We assessed the oxidative potential (OP) of both water-soluble and methanol-soluble fractions of ambient fine particulate matter (PM2.5) in the midwestern United States. A large set of PM2.5 samples (N = 241) were collected from five sites, setup in different environments, i.e. urban, rural and roadside, in Illinois, Indiana and Missouri during May 2018–May 2019. Five acellular OP endpoints, including the consumption rate of ascorbic acid and glutathione in a surrogate lung fluid (SLF) (OPAA and OPGSH, respectively), dithiothreitol (DTT) depletion rate (OPDTT), and ·OH generation rate in SLF and DTT (OPOH-SLF and OPOH-DTT, respectively), were measured for all PM2.5 samples. PM2.5 mass concentrations in the Midwest US as obtained from these samples were spatially homogeneously distributed, while most OP endpoints showed significant spatiotemporal heterogeneity. Seasonally, higher activities occurred in summer for most OP endpoints for both water- and methanol-soluble extracts. Spatially, roadside site showed highest activities for most OP endpoints in the water-soluble extracts, while only occasional peaks were observed at urban sites in the methanol-soluble OP. Most OP endpoints showed similar spatiotemporal trends between mass- and volume-normalized activities across different sites and seasons. Comparisons between two solvents (i.e. water and methanol) showed that methanol-soluble OP generally had higher activity levels than corresponding water-soluble OP. Site-to-site comparisons of OP showed stronger correlations for methanol-soluble OP compared to water-soluble OP, indicating a better extraction of water-insoluble redox-active compounds from various emission sources into methanol. We found a weak correlation and inconsistent slope values between PM2.5 mass and most OP endpoints. Moreover, the poor-to-moderate intercorrelations among different OP endpoints infer different mechanisms of OP represented by these endpoints, and thus demonstrate the rationale for analyzing multiple acellular endpoints for a better and comprehensive assessment of OP.

scholarly journals A Semi-automated Instrument for Cellular Oxidative Potential Evaluation (SCOPE) of Water-soluble Extracts of Ambient Particulate Matter

2021 ◽  
Author(s):  
Sudheer Salana ◽  
Yixiang Wang ◽  
Joseph Puthussery ◽  
Vishal Verma
Keyword(s):  
Particulate Matter ◽  
Chemical Species ◽  
Positive Control ◽  
Water Soluble ◽  
Ros Generation ◽  
Ambient Particulate Matter ◽  
Oxidative Potential ◽  
Cellular Assays ◽  
Potential Evaluation ◽  
Automated Instrument

Abstract. Several automated instruments exist to measure the acellular oxidative potential (OP) of ambient particulate matter (PM). However, cellular OP of the ambient PM is still measured manually, which severely limits the comparison between two types of assays. Cellular assays could provide a more comprehensive assessment of the PM-induced oxidative stress, as they incorporate more biological processes involved in the PM-catalyzed reactive oxygen species (ROS) generation. Considering this need, we developed a first of its kind semi-automated instrument for measuring the cellular OP based on a macrophage ROS assay using rat alveolar macrophages. The instrument named SCOPE – Semi-automated instrument for Cellular Oxidative Potential Evaluation, uses dichlorofluorescein diacetate (DCFH-DA) as a probe to detect the OP of PM samples extracted in water. SCOPE is capable of analyzing a batch of six samples (including one negative and one positive control) in five hours and is equipped to operate continuously for 24-hours with minimal manual intervention after every batch of analysis, i.e., after every five hours. SCOPE has a high analytical precision as assessed from both positive controls and ambient PM samples (CoV < 17 %). The results obtained from the instrument were in good agreement with manual measurements using tert-Butyl hydroperoxide (t-BOOH) as the positive control (slope = 0.83 for automated vs. manual, R2 = 0.99) and ambient samples (slope = 0.83, R2 = 0.71). We further demonstrated the ability of SCOPE to analyze a large number of both ambient and laboratory samples, and developed a dataset on the intrinsic cellular OP of several compounds, such as metals, quinones, PAHs and inorganic salts, commonly known to be present in ambient PM. This dataset is potentially useful in future studies to apportion the contribution of key chemical species in the overall cellular OP of ambient PM.

scholarly journals A semi-automated instrument for cellular oxidative potential evaluation (SCOPE) of water-soluble extracts of ambient particulate matter

2021 ◽  
Vol 14 (12) ◽  
pp. 7579-7593
Author(s):  
Sudheer Salana ◽  
Yixiang Wang ◽  
Joseph V. Puthussery ◽  
Vishal Verma
Keyword(s):  
Particulate Matter ◽  
Chemical Species ◽  
Positive Control ◽  
Water Soluble ◽  
Ros Generation ◽  
Ambient Particulate Matter ◽  
Oxidative Potential ◽  
Cellular Assays ◽  
Potential Evaluation ◽  
Automated Instrument

Abstract. Several automated instruments exist to measure the acellular oxidative potential (OP) of ambient particulate matter (PM). However, cellular OP of the ambient PM is still measured manually, which severely limits the comparison between two types of assays. Cellular assays could provide a more comprehensive assessment of the PM-induced oxidative stress, as they incorporate more biological processes involved in the PM-catalyzed reactive oxygen species (ROS) generation. Considering this need, we developed a semi-automated instrument, the first of its kind, for measuring the cellular OP based on a macrophage ROS assay using rat alveolar macrophages. The instrument named SCOPE – semi-automated instrument for cellular oxidative potential evaluation – uses dichlorofluorescein diacetate (DCFH-DA) as a probe to detect the OP of PM samples extracted in water. SCOPE is capable of analyzing a batch of six samples (including one negative and one positive control) in 5 h and is equipped to operate continuously for 24 h with minimal manual intervention after every batch of analysis, i.e., after every 5 h. SCOPE has a high analytical precision as assessed from both positive controls and ambient PM samples (coefficient of variation (CoV)<17 %). The results obtained from the instrument were in good agreement with manual measurements using tert-butyl hydroperoxide (t-BOOH) as the positive control (slope =0.83 for automated vs. manual, R2=0.99) and ambient samples (slope =0.83, R2=0.71). We further demonstrated the ability of SCOPE to analyze a large number of both ambient and laboratory samples and developed a dataset on the intrinsic cellular OP of several compounds, such as metals, quinones, polycyclic aromatic hydrocarbons (PAHs) and inorganic salts, commonly known to be present in ambient PM. This dataset is potentially useful in future studies to apportion the contribution of key chemical species in the overall cellular OP of ambient PM.

scholarly journals Development and field-testing of an online instrument for measuring the real-time oxidative potential of ambient particulate matter based on dithiothreitol assay

2018 ◽  
Author(s):  
Joseph V. Puthussery ◽  
Chen Zhang ◽  
Vishal Verma
Keyword(s):  
Particulate Matter ◽  
Organic Carbon ◽  
Water Soluble ◽  
Urban Site ◽  
Activity Levels ◽  
Ambient Particulate Matter ◽  
Oxidative Potential ◽  
Pump System ◽  
Activity Measurements ◽  
Diurnal Profile

Abstract. We developed an online instrument for measuring the oxidative potential (OP) of ambient particulate matter (PM) using dithiothreitol (DTT) assay. The instrument uses a mist chamber (MC) to continuously collect the ambient PM2.5 in water, followed by its DTT activity determination using an automated syringe pump system. The instrument was deployed at an urban site in the University of Illinois campus, and its field performance was evaluated by comparing the results with the offline DTT activity measurements of simultaneously collected PM-laden filters. The online DTT activity measurements correlated well with the offline measurements but were higher than both methanol (slope = 0.86, R2 = 0.93) and Milli-Q water (slope = 0.52, R2 = 0.86) extracts of the PM filters, indicating a better efficiency of MC for collecting the water-insoluble fraction of PM. The hourly measurements of ambient PM2.5 OP were obtained by running the online instrument intermittently for 50 days with minimal manual assistance. The daytime DTT activity levels were generally higher than at night. However, a four-fold increase in the hourly averaged activity was observed on the night of July 04 (Independence Day fireworks display). Diurnal profile of the hourly averaged OP during weekdays showed a bimodal trend, with a sharp peak in the morning (around 7:00 AM), followed by a broader afternoon peak, which plateaus around 2:00 PM, and starts subsiding at night (around 7:00 PM). To investigate the association of the diurnal profile of DTT activity with the emission sources at the site, we collected time-segregated composite PM filter samples in four different time periods of the day [morning (7:00 AM–10:00 AM), afternoon (10:00 AM–3:00 PM), evening (3:00 PM–7:00 PM) and night (7:00 PM–7:00 AM)] and determined the diurnal variations in the redox active components [i.e. water soluble Cu, Fe, Mn, organic carbon, elemental carbon and water soluble organic carbon]. Based on this comparison, we attributed the daytime OP of ambient PM2.5 to the water-soluble Cu from both exhaust and non-exhaust emissions, whereas secondary particles formed by the photochemical transformation of primary emissions appear to enhance the OP of PM during the afternoon and evening period.

scholarly journals Development and field testing of an online instrument for measuring the real-time oxidative potential of ambient particulate matter based on dithiothreitol assay

2018 ◽  
Vol 11 (10) ◽  
pp. 5767-5780 ◽  
Author(s):  
Joseph V. Puthussery ◽  
Chen Zhang ◽  
Vishal Verma
Keyword(s):  
Particulate Matter ◽  
Organic Carbon ◽  
Water Soluble ◽  
Urban Site ◽  
Activity Levels ◽  
Ambient Particulate Matter ◽  
Oxidative Potential ◽  
Pump System ◽  
Activity Measurements ◽  
Diurnal Profile

Abstract. We developed an online instrument for measuring the oxidative potential (OP) of ambient particulate matter (PM) using the dithiothreitol (DTT) assay. The instrument uses a mist chamber (MC) to continuously collect the ambient PM2.5 in water, and then determines its DTT activity using an automated syringe pump system. The instrument was deployed at an urban site in the University of Illinois campus, and its field performance was evaluated by comparing the results with the offline DTT activity measurements of simultaneously collected PM-laden filters. The online DTT activity measurements correlated well with the offline measurements but were higher than both methanol (slope =1.08, R2=0.93) and Milli-Q water (slope =1.86, R2=0.86) extracts of the PM filters, indicating a better efficiency of the MC for collecting the water-insoluble fraction of PM. The hourly measurements of ambient PM2.5 OP were obtained by running the online instrument intermittently for 50 days with minimal manual assistance. The daytime DTT activity levels were generally higher than at night. However, a 4-fold increase in the hourly averaged activity was observed on the night of 4 July (Independence Day fireworks display). The diurnal profile of the hourly averaged OP during weekdays showed a bimodal trend, with a sharp peak in the morning (around 07:00 LT), followed by a broader afternoon peak which plateaus around 14:00 LT and starts subsiding at night (around 19:00 LT). To investigate the association of the diurnal profile of DTT activity with the emission sources at the site, we collected time-segregated composite PM filter samples in four different time periods of the day (morning, 07:00–10:00 LT; afternoon, 10:00–15:00 LT; evening, 15:00–19:00 LT; and night, 19:00–07:00 LT) and determined the diurnal variations in the redox active components (i.e., water-soluble Cu, Fe, Mn, organic carbon, elemental carbon, and water-soluble organic carbon). Based on this comparison, we attributed the daytime OP of ambient PM2.5 to the vehicular (both exhaust and non-exhaust) emissions and resuspended dust, whereas secondary photochemical transformation of primary emissions appear to enhance the OP of PM during the afternoon and evening period.

Sign in / Sign up

Export Citation Format

Share Document