Development and Application of a Sensitive Method to Determine Concentrations of Acrolein and Other Carbonyls in Ambient AirEPA Grant Number: R834677C149
Subproject: this is subproject number 149 , established and managed by the Center Director under grant R834677
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Health Effects Institute (2010 — 2015)
Center Director: Greenbaum, Daniel S.
Title: Development and Application of a Sensitive Method to Determine Concentrations of Acrolein and Other Carbonyls in Ambient Air
Investigators: Cahill, Thomas M
Institution: Arizona State University , Health Effects Institute (HEI)
EPA Project Officer: Chung, Serena
Project Period: April 1, 2010 through March 31, 2015
RFA: Health Effects Institute (2010) RFA Text | Recipients Lists
Research Category: Health Effects , Air Quality and Air Toxics , Air
Acrolein is a reactive aldehyde that injures the airways in humans and other species, and the U.S. Environmental Protection Agency lists it among the mobile-source air toxics that pose the greatest health risk. Information on the acrolein concentrations to which people are exposed is an important prerequisite for assessing the risk to human health. Despite some technological improvements, it remains difficult to accurately measure acrolein at low levels because, upon collection, it rapidly forms unstable intermediates that are difficult to differentiate and quantify.
Dr. Judith Charles of the University of California–Davis proposed the develop a new method for measuring low levels of acrolein, crotonaldehyde, and other unstable aldehydes and apply the new method to assess exposure of tollbooth attendants in the San Francisco Bay area. During the middle of the second year, Dr. Charles became ill, and Dr. Thomas Cahill replaced her as the principal investigator and completed the study.
The investigators proposed to evaluate a sampling method that relies on the collection of acrolein in an aqueous medium containing sodium bisulfite, with which it forms a stable chemical reaction product. The overall aim of the study was to develop and optimize a method for the collection and analysis of acrolein and to evaluate the performance of the method by three different measures. One measure was collection efficiency, calculated as the concentration of acrolein in the first of two mist chambers in series relative to that in the second chamber, expressed as a percentage. The second measure was “spike recovery” (also defined as the mass balance), a measure of the overall carbonyl recovery, from collection to analysis. It was determined by adding a known carbonyl mass to a “spiking tube” placed upstream of the mist chamber and delivering it to the chamber by blowing pure nitrogen through the tube to simulate ambient collection conditions. Recovery was calculated as the percentage of the carbonyl mass in both chambers and remaining in the spiking tube relative to the mass added initially. The third measure was retention of deuterated acrolein-d4 that had been added directly to the bisulfite solution as an internal standard before sampling, expressed as a percentage of the initial amount. The investigators also measured acrolein levels in two field studies and compared the results with those obtained by other sampling methods.
The sampler developed by Charles and Cahill, with Dr. Vincent Seaman, consists of a custom-built glass mist chamber in which air enters at a high flow rate and carbonyls are trapped in a solution of sodium bisulfite as carbonyl-bisulfite adducts. This reaction is rapid (on the order of seconds) for all the carbonyls tested, and its rate is dependent on the concentration of bisulfite. The optimal sampling time for acrolein and the other carbonyls is 10 to 30 minutes at a flow rate of approximately 20 L/min at 21C, and the optimal setup is two mist chambers in series. Longer sampling times, lower flow rates, and different temperatures were not evaluated. After collection, hydrogen peroxide is added to free the carbonyl from the adduct, and a derivatizing agent is added to form a carbonyl derivative suitable for gas chromatography with mass spectrometry. The calculated minimum detection limit for acrolein varied between experiments and ranged from 0.012 μg/m3 (0.005 ppb) to 0.035 μg/m3 (0.015 ppb), values well below the detection limits of other existing methods .
The collection efficiency of the mist chamber methodology was determined to be 80% in the laboratory and 71% in the field. Assuming that the collection efficiency is the same in the two chambers, it would be approximately 91% for the whole system in the field. This is only a relative measure of collection because it does not consider the initial amount of acrolein. Using the spike-recovery approach, the investigators found that 97% of the acrolein mass was recovered. For this test acrolein was dissolved in solvent and volatilized into a nitrogen stream. Although this approach was designed to simulate sampling in the field, it may not reflect entirely the actual conditions to which acrolein is exposed when sampled in ambient air. The test using the deuterated internal standard showed that, once the acrolein was trapped, 93% was retained throughout theanalytic process. Because the deuterated species was dissolved in the bisulfite solution in the mist chamber, rather than bubbled into the solution in an air stream (as it would be under ambient sampling conditions), the measure of internal standard retention does not evaluate the efficiency with which the carbonyl in the ambient air stream is trapped in the mist chamber solution. Overall, the Review Committee—in its independent evaluation of the study—thought that these analyses were useful and showed a high level of acrolein recovery under laboratory conditions. However, the dynamic processes that lead to absorption of acrolein in the field may vary.
Supplemental Keywords:Health Effects, Air Toxics, VOCs, acrolein, epidemiology, carcinogens, exposure models, aldehyde, mobile source air toxics, mist chamber methodology, carbonyls, ambient air sampling
Main Center Abstract and Reports:R834677 Health Effects Institute (2010 — 2015)
Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R834677C149 Development and Application of a Sensitive Method to Determine Concentrations of Acrolein and Other Carbonyls in Ambient Air
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R834677C151 Biologic Effects of Inhaled Diesel Exhaust in Young and Old Mice: A Pilot Project
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R834677C153 Improved Source Apportionment and Speciation of Low-Volume Particulate Matter Samples
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R834677C156 Concentrations of Air Toxics in Motor Vehicle-Dominated Environments
R834677C158 Air Toxics Exposure from Vehicle Emissions at a U.S. Border Crossing: Buffalo Peace Bridge Study
R834677C159 Role of Neprilysin in Airway Inflammation Induced by Diesel Exhaust Emissions
R834677C160 Personal and Ambient Exposures to Air Toxics in Camden, New Jersey
R834677C162 Assessing the Impact of a Wood Stove Replacement Program on Air Quality and Children’s Health
R834677C163 The London Low Emission Zone Baseline Study
R834677C165 Effects of Controlled Exposure to Diesel Exhaust in Allergic Asthmatic Individuals
R834677C168 Evaluating the Effects of Title IV of the 1990 Clean Air Act Amendments on Air Quality
R834677C172 Potential Air Toxics Hot Spots in Truck Terminals and Cabs
R834677C173 Detection and Characterization of Nanoparticles from Motor Vehicles
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