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Title: Source-dependent variation in hydroxyl radical production by airborne particulate matter

Abstract

Epidemiological studies suggest exposure to airborne particles is responsible for a wide range of adverse health effects, potentially arising from particle-induced oxidative stress. A highly sensitive fluorescence method was employed to measure the production of hydroxyl radical by a broad range of particle types including urban dust, diesel particulate matter, coal fly ash, kaolinite, and silica. Little or no production of OH was observed in the absence of an added electron donor or H{sub 2}O{sub 2}. In the presence of a biological electron donor (NADPH, 3 mM), the rate of OH production (R{sub OH}) for 3 mg/mL of these particles varied from 23 nM s{sup -1} for diesel particulate matter (SRM 2975) to 0.20 nM s{sup -1} for coal fly ash (SRM 2689). No detectable OH was produced by kaolinite or silica. Hydroxyl radical formation was eliminated under anaerobic conditions and in the presence of catalase, indicating that O{sub 2} and H{sub 2}O{sub 2} are required for its generation. Partial inhibition of OH formation by superoxide dismutase (SOD) was also observed in some cases, suggesting that superoxide is also involved. The metal chelator deferoxamine mesylate (DFX) in most cases suppressed OH formation, but diethylenetriaminepentaacetic acid (DTPA) generally enhanced it, implicatingmore » metal ion reactions in OH generation as well. The dependence of R{sub OH} on NADPH concentration further implicates particle surface reactions in OH formation. To the authors' knowledge, these measurements provide the first quantitative estimate of ROH for a broad range of particle types. 49 refs., 6 figs., 1 tab.« less

Authors:
;  [1]
  1. University of Maryland, College Park, MD (United States). Department of Chemistry and Biochemistry
Publication Date:
OSTI Identifier:
20885849
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Science and Technology; Journal Volume: 41; Journal Issue: 7; Other Information: neilb@umd.edu
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; 54 ENVIRONMENTAL SCIENCES; 02 PETROLEUM; COAL; FLY ASH; PARTICULATES; FLUORESCENCE; KAOLINITE; SILICA; DIESEL FUELS; POLLUTION SOURCES; AIR POLLUTION; EPIDEMIOLOGY; HYDROXYL RADICALS; HEALTH HAZARDS; CHEMICAL REACTION KINETICS; AEROBIC CONDITIONS; LEWIS BASES; HYDROGEN PEROXIDE; QUANTITATIVE CHEMICAL ANALYSIS

Citation Formats

Marjan Alaghmand, and Neil V. Blough. Source-dependent variation in hydroxyl radical production by airborne particulate matter. United States: N. p., 2007. Web. doi:10.1021/es061902o.
Marjan Alaghmand, & Neil V. Blough. Source-dependent variation in hydroxyl radical production by airborne particulate matter. United States. doi:10.1021/es061902o.
Marjan Alaghmand, and Neil V. Blough. Sun . "Source-dependent variation in hydroxyl radical production by airborne particulate matter". United States. doi:10.1021/es061902o.
@article{osti_20885849,
title = {Source-dependent variation in hydroxyl radical production by airborne particulate matter},
author = {Marjan Alaghmand and Neil V. Blough},
abstractNote = {Epidemiological studies suggest exposure to airborne particles is responsible for a wide range of adverse health effects, potentially arising from particle-induced oxidative stress. A highly sensitive fluorescence method was employed to measure the production of hydroxyl radical by a broad range of particle types including urban dust, diesel particulate matter, coal fly ash, kaolinite, and silica. Little or no production of OH was observed in the absence of an added electron donor or H{sub 2}O{sub 2}. In the presence of a biological electron donor (NADPH, 3 mM), the rate of OH production (R{sub OH}) for 3 mg/mL of these particles varied from 23 nM s{sup -1} for diesel particulate matter (SRM 2975) to 0.20 nM s{sup -1} for coal fly ash (SRM 2689). No detectable OH was produced by kaolinite or silica. Hydroxyl radical formation was eliminated under anaerobic conditions and in the presence of catalase, indicating that O{sub 2} and H{sub 2}O{sub 2} are required for its generation. Partial inhibition of OH formation by superoxide dismutase (SOD) was also observed in some cases, suggesting that superoxide is also involved. The metal chelator deferoxamine mesylate (DFX) in most cases suppressed OH formation, but diethylenetriaminepentaacetic acid (DTPA) generally enhanced it, implicating metal ion reactions in OH generation as well. The dependence of R{sub OH} on NADPH concentration further implicates particle surface reactions in OH formation. To the authors' knowledge, these measurements provide the first quantitative estimate of ROH for a broad range of particle types. 49 refs., 6 figs., 1 tab.},
doi = {10.1021/es061902o},
journal = {Environmental Science and Technology},
number = 7,
volume = 41,
place = {United States},
year = {Sun Apr 01 00:00:00 EDT 2007},
month = {Sun Apr 01 00:00:00 EDT 2007}
}
  • Exposure to ambient particulate matter (PM) has been reported to be associated with increased respiratory, cardiovascular, and malignant lung disease. Previously we have shown that PM can induce oxidative DNA damage in A549 human lung epithelial cells. The aims of the present study were to investigate the variability of the DNA-damaging properties of PM sampled at different locations and times and to relate the observed effects to the hydroxyl-radical ({center_dot}OH)-generating activities of these samples. Weekly samples of coarse (10-2.5 {mu}m) and fine (<2.5 {mu}m) PM from four sites (Nordrheim Westfalen, Germany) were analyzed for hydrogen-peroxide-dependent {center_dot}OH formation using electron paramagneticmore » resonance and formation of 8-hydroxydeoxyguanosine (8-OHdG) in calf thymus DNA using an immuno-dot-blot assay. DNA strand breakage by fine PM in A549 human lung epithelial cells was quantified using the alkaline comet assay. Both PM size distribution fractions elicited {center_dot}OH generation and 8-OHdG formations in calf thymus DNA. Significantly higher {center_dot}OH generation was observed for PM sampled at urban/industrial locations and for coarse PM. Samples of fine PM also caused DNA strand breakage in A549 cells and this damage could be prevented using the hydroxyl-radical scavengers 5,5-dimethyl-1-pyrroline-N-oxide and dimethyl sulfoxide. The observed DNA strand breakage appeared to correlate with the hydroxyl-radical-generating capacities of the PM samples but with different profiles for rural versus urban/industrial samples. In conclusion, when considered at equal mass, {center_dot}OH formation of PM shows considerable variability with regard to the sampling location and time and is correlated with its ability to cause DNA damage.« less
  • This paper reports that to test the recent advances in receptor modeling for the identification of long-range transport of regional source signatures of airborne particulate matter, an epithermal irradiation facility to determine indium has been specifically constructed. Analysis of filter samples collected weekly over a 5-yr period has indicated that indium in the arctic atmosphere is strongly dependent on season. Typical detection limits were 0.1 ng per one-eighth of a 20.3 {times} 25.4-cm Whatman filter. The airborne concentrations of indium are extremely elevated in the winter and spring months, and they almost disappear in the summer months. The application ofmore » the potential source contribution function has indicated that the indium originates from several areas in Eurasia as well as from known hot spots in North America.« less
  • Aerosol composition data from the Speciation Trends Network (STN) site (East 14th Street) in Cleveland, OH, were analyzed by advanced receptor model methods for source apportionment as well as by the standard positive matrix factorization (PMF) using PMF2. These different models are used in combination to test model limitations. These data were 24-hr average mass concentrations and compositions obtained for samples taken every third day from 2001 to 2003. The Multilinear Engine (ME) was used to solve an expanded model to estimate the source profiles and source contributions and also to investigate the wind speed, wind direction, time-of-day, weekend/weekday, andmore » seasonal effects. PMF2 was applied to the same dataset. Potential source contribution function (PSCF) and conditional probability function (CPF) analyses were used to locate the regional and local sources using the resolved source contributions and appropriate meteorological data. Very little difference was observed between the results of the expanded model and the PMF2 values for the profiles and source contribution time series. The identified sources were as ferrous smelter, secondary sulfate, secondary nitrate, soil/combustion mixture, steel mill, traffic, wood smoke, and coal burning. The CPF analysis was useful in helping to identify local sources, whereas the PSCF results were only useful for regional source areas. Both of these analyses were more useful than the wind directional factor derived from the expanded factor analysis. However, the expanded analysis provided direct information on seasonality and day-of-week behavior of the sources. 28 refs., 8 figs., 4 tabs.« less
  • A one-dimensional aerosol model is used to investigate the sensitivity of the stratospheric distributions of gaseous sulfur compounds and sulfate aerosol particles to changes in OH and CS/sub 2/ concentrations, in eddy diffusion coefficients, and in key chemical rate constants. By comparing model predictions with recent observational data for So/sub 2/, OCS, and particulates, the following conclusions are reached. With regard to atmospheric sulfur, it appears that CS/sub 2/ is only a secondary source of sulfur for the stratosphere relative to OCS and that background tropospheric CS/sub 2/ concentrations are likely to be <70 pptv. It is also found thatmore » under stratospheric conditions, the rate coefficients for the reactions of OH with OCS and CS/sub 2/ may be substantially smaller than the room temperature laboratory values of Kurylo (1978). The most important conclusion of the present study, however, is that OH concentrations below 30 km may be over-estimated by a factor of 3 or more in current photochemical models. Plausibility arguments for lower atmospheric OH concentrations are supported by recent laboratory studies of the pressure, the temperature, and the humidity dependences of OH an HO/sub 2/ chemical kinetic systems. New reaction rate data bearing on this problem are reviewed. A reduced level of stratospheric OH has strong implications for ozone perturbations attributable to aircraft NO/sub x/ emissions, to nitrogen fertilizer usage, and to halocarbon releases. Such ozone perturbations are simulated using a one-dimensional atmospheric photochemistry model in which the OH concentrations are reduced in accordance with the sulfur sensitivity tests highlighted above. Owing to the reduction in OH, SST NO/sub x/ injections at 20 km act to decrease ozone, not increase it as had been thought previously. Nitrous oxide produced by fertilizer decomposition is also found to be more destructive of ozone. On the other hand, fluorocarbon-induced ozone depletions are somewhat smaller.« less
  • Remediation of hydrophobic pollutants is complicated by sorption of these compounds to hydrophobic sites of dissolved natural organic matter (NOM), suspended particulates, soil, and sediment. This sorption causes the pollutants to be less easily degraded by remediation techniques. Reaction of aromatic compounds with hydroxyl radical is inhibited by dissolved natural organic matter (NOM). The degree of inhibition is significantly greater than that expected based on a simple model in which aromatic compound molecules bound to NOM are considered to be unreactive. In this study, hydroxyl radical was produced at steady-state concentrations using Fenton chemistry (H{sub 2}O{sub 2} + Fe{sup 2+}more » {yields} Fe{sup 3+} + HO{sup {minus}} + HO{sm_bullet}). Suwannee River fulvic acid and humic acid were used as NOM. The most likely mechanism for the observed inhibition is that hydroxyl radical formation occurs in microenvironmental sites remote from the aromatic compounds. In addition to changes in kinetics, pyrene hydroxyl radical reaction also exhibited a mechanistic change in the presence of fulvic acid. The mechanism changed from a reaction that was apparently first-order in pyrene to one that was apparently second-order in pyrene, indicating that pyrene self-reaction may have become the dominant mechanism in the presence of fulvic acid. Dissolved NOM causes significant changes in the rate and mechanism of hydroxyl radical degradation of aromatic compounds. Consequently, literature rate constants measured in pure water will not be useful for predicting the degradation of pollutants in environmental systems. The kinetic and mechanistic information in this study will be useful for developing improved degradation methods involving Fenton chemistry.« less