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Yelverton TLB, Hays MD, Rice J. Ethylene Oxide: An Air Contaminant of Concern. ACS ES&T AIR 2024; 1:747-754. [PMID: 39144753 PMCID: PMC11320571 DOI: 10.1021/acsestair.4c00053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 08/16/2024]
Abstract
Ethylene oxide (EtO) is a colorless, flammable, reactive gas commonly used for sterilization and chemical manufacturing. It has become a contaminant of concern for the United States Environmental Protection Agency (USEPA) due to an assessment of its toxicity, which found that EtO is more potent than had been previously understood and which also revised the weight-of-evidence classification of EtO from "probably carcinogenic" to "carcinogenic to humans". With the revised toxicity assessment came findings of increased cancer risk to communities near some facilities that emit EtO to ambient air, including communities with environmental justice (EJ) concerns. To address EtO, the USEPA has conducted intensive research in recent years, centering its attention on measurement and sampling technology development, as well as monitoring of EtO in source emissions, near-source air, and atmospheric environments to further support science-based policy and regulations that reduce harmful impacts to human health. Research efforts by government, academic, and commercial institutions have resulted in the development of novel measurement and monitoring techniques, which has led to more robust characterization of EtO emissions and atmospheric levels across a wide range of concentrations, including trace levels (ppt). This Perspective covers the importance of capturing high quality, analytical measurements of EtO, what is known so far about these measurement technologies, EPA's response to the increasing concerns of EtO contamination, what still needs to be accomplished on the air quality front, and a focus on USEPA research and development moving forward.
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Affiliation(s)
- Tiffany L. B. Yelverton
- U.S.
Environmental Protection Agency Office of Research and Development
Center for Environmental Measurement and Modeling, Research Triangle Park, North Carolina 27711, United States
| | - Michael D. Hays
- U.S.
Environmental Protection Agency Office of Research and Development
Center for Environmental Measurement and Modeling, Research Triangle Park, North Carolina 27711, United States
| | - Joann Rice
- U.
S. Environmental Protection Agency Office of Air and Radiation Office
of Air Quality Planning and Standards Research Triangle Park, North Carolina 27711, United States
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Robinson E, Tehrani MW, Yassine A, Agarwal S, Nault BA, Gigot C, Chiger AA, Lupolt SN, Daube C, Avery AM, Claflin MS, Stark H, Lunny EM, Roscioli JR, Herndon SC, Skog K, Bent J, Koehler K, Rule AM, Burke T, Yacovitch TI, Nachman K, DeCarlo PF. Ethylene Oxide in Southeastern Louisiana's Petrochemical Corridor: High Spatial Resolution Mobile Monitoring during HAP-MAP. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:11084-11095. [PMID: 38860676 PMCID: PMC11210204 DOI: 10.1021/acs.est.3c10579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 05/03/2024] [Accepted: 05/03/2024] [Indexed: 06/12/2024]
Abstract
Ethylene oxide ("EtO") is an industrially made volatile organic compound and a known human carcinogen. There are few reliable reports of ambient EtO concentrations around production and end-use facilities, however, despite major exposure concerns. We present in situ, fast (1 Hz), sensitive EtO measurements made during February 2023 across the southeastern Louisiana industrial corridor. We aggregated mobile data at 500 m spatial resolution and reported average mixing ratios for 75 km of the corridor. Mean and median aggregated values were 31.4 and 23.3 ppt, respectively, and a majority (75%) of 500 m grid cells were above 10.9 ppt, the lifetime exposure concentration corresponding to 100-in-one million excess cancer risk (1 × 10-4). A small subset (3.3%) were above 109 ppt (1000-in-one million cancer risk, 1 × 10-3); these tended to be near EtO-emitting facilities, though we observed plumes over 10 km from the nearest facilities. Many plumes were highly correlated with other measured gases, indicating potential emission sources, and a subset was measured simultaneously with a second commercial analyzer, showing good agreement. We estimated EtO for 13 census tracts, all of which were higher than EPA estimates (median difference of 21.3 ppt). Our findings provide important information about EtO concentrations and potential exposure risks in a key industrial region and advance the application of EtO analytical methods for ambient sampling and mobile monitoring for air toxics.
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Affiliation(s)
- Ellis
S. Robinson
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Mina W. Tehrani
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Amira Yassine
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Shivang Agarwal
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Benjamin A. Nault
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
- Center
for Aerosol and Cloud Chemistry, Aerodyne
Research, Inc., Billerica, Massachusetts 01821, United States
| | - Carolyn Gigot
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Andrea A. Chiger
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
- The
Risk Sciences and Public Policy Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, United States
| | - Sara N. Lupolt
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
- The
Risk Sciences and Public Policy Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, United States
| | - Conner Daube
- Center
for Atmospheric and Environmental Chemistry, Aerodyne Research, Inc., Billerica, Massachusetts 01821, United States
| | - Anita M. Avery
- Center
for Aerosol and Cloud Chemistry, Aerodyne
Research, Inc., Billerica, Massachusetts 01821, United States
| | - Megan S. Claflin
- Center
for Aerosol and Cloud Chemistry, Aerodyne
Research, Inc., Billerica, Massachusetts 01821, United States
| | - Harald Stark
- Center
for Aerosol and Cloud Chemistry, Aerodyne
Research, Inc., Billerica, Massachusetts 01821, United States
- Department
of Chemistry and Cooperative Institute for Research in Environmental
Sciences, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Elizabeth M. Lunny
- Center
for Atmospheric and Environmental Chemistry, Aerodyne Research, Inc., Billerica, Massachusetts 01821, United States
| | - Joseph R. Roscioli
- Center
for Atmospheric and Environmental Chemistry, Aerodyne Research, Inc., Billerica, Massachusetts 01821, United States
| | - Scott C. Herndon
- Center
for Atmospheric and Environmental Chemistry, Aerodyne Research, Inc., Billerica, Massachusetts 01821, United States
| | - Kai Skog
- Picarro,
Inc., Santa Clara, California 95054, United States
| | - Jonathan Bent
- Picarro,
Inc., Santa Clara, California 95054, United States
| | - Kirsten Koehler
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Ana M. Rule
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Thomas Burke
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
- The
Risk Sciences and Public Policy Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, United States
| | - Tara I. Yacovitch
- Center
for Atmospheric and Environmental Chemistry, Aerodyne Research, Inc., Billerica, Massachusetts 01821, United States
| | - Keeve Nachman
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
- The
Risk Sciences and Public Policy Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, United States
| | - Peter F. DeCarlo
- Department
of Environmental Health and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States
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Mei EJ, Moore AC, Kaiser J. Suitability of new and existing ambient ethylene oxide measurement techniques for cancer inhalation risk assessment. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 336:122481. [PMID: 37660772 DOI: 10.1016/j.envpol.2023.122481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/05/2023]
Abstract
Ethylene oxide (EtO) is an industrial gas that was recently reassessed to pose significant additional cancer risk at low ambient concentrations. The objective of this study is to evaluate the capabilities of existing and novel techniques to measure ambient EtO at concentrations relevant for assessing cancer risk. We present the first comparison of background ambient EtO measurements between the standard offline TO-15 techniques and two new cavity ringdown spectroscopy (CRDS) instruments, the Picarro G2920 Ethylene Oxide Gas Analyzer and the Entanglement Technologies AROMA-ETO, at a site in Atlanta, GA. Then, we analyzed background EtO measured at EPA NATTS sites across the US. Finally, we used TO-15 measurement data to assess EtO cancer risk at three near-source sites. We find that the TO-15 method has low precision for collocated samples (NME ranges from 24% to 63%), and measurements made with TO-15 pressurized samplers are biased 27% low compared to those from TO-15 passive samplers. Both CRDS methods are biased low compared to TO-15 methods (88% and 31% low bias for Picarro and AROMA, respectively), and TO-15 methods observe a seasonal peak during summer (June to September) whereas Picarro observes no seasonal trend. From our near-source assessment, we find only one site with notable elevation in cancer risk prior to EtO controls installation. Our results suggest that measurement techniques need further development to accurately assess near-source EtO cancer risk. Because different techniques measure distinct EtO trends, EtO cancer risk studies that rely on current measurement capabilities should subtract simultaneous background observations from near-source observations measured by the same method to account for these real or artificial background trends.
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Affiliation(s)
- Eric John Mei
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Aryiana Cemari Moore
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Jennifer Kaiser
- School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA; School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, 30332, USA.
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Soleimanian E, Wang Y, Estes M. Long-term trend in surface ozone in Houston-Galveston-Brazoria: Sectoral contributions based on changes in volatile organic compounds. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 308:119647. [PMID: 35718047 DOI: 10.1016/j.envpol.2022.119647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 05/23/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
This study investigated the long-term variations in ambient levels of surface ozone, volatile organic compounds (VOCs), and nitrogen oxides (NOx) within the Houston-Galveston-Brazoria (HGB) region. Analysis of ozone levels revealed an overall reduction in the maximum daily 8-h average ozone (MDA8 O3) from 2000 to 2019 (April-October) with an average rate of ∼ -0.48 ppb/yr across HGB. With a few exceptions, the MDA8 O3 reduction rates were more pronounced for the monitoring sites closer to the Houston Ship Channel (HSC). Meanwhile, ambient levels of NOx and most VOC species (across the three representative sites as Houston Bayland Park, Haden Road, and Lynchburg Ferry) decreased significantly within the same investigation period, reflecting the impact of emission reductions. The positive matrix factorization (PMF) model applied to the mentioned sites identified regional background ozone, petrochemical emissions, engine combustion, natural gas/fuel evaporation, and solvent/painting/rubber industries as the major sources of MDA8 O3. The regional background ozone was the predominant source, accounting for 59-70% of MDA8 O3 across the three sites. Regarding the local anthropogenic emissions, natural gas/fuel evaporation was the largest contributor (19.5 ± 6.1%) to MDA8 O3 at Houston Bayland Park, whereas petrochemical facilities (10.9 ± 4.9%) and solvent/painting/rubber industries (18.1 ± 9.5%) were the largest factor at Haden Road and Lynchburg Ferry, respectively. Notable reductions were found in the contributions of petrochemical emissions, engine combustion, and natural gas/fuel evaporation to MDA8 O3 within 2000-2019, but an increasing trend was revealed in the role of solvent/painting/rubber industries on MDA8 O3 most probably due to the enhanced demand for their products. Results of this study corroborated the success of emission control policies in limiting ozone precursors and provided useful details for prioritizing emission reduction policies to further reduce ozone pollution in the HGB.
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Affiliation(s)
- Ehsan Soleimanian
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USA.
| | - Yuxuan Wang
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX, USA.
| | - Mark Estes
- Institute for Interdisciplinary Science, St. Edward's University, Austin, TX, USA.
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n-Octyltrichlorosilane Modified SAPO-34/PDMS Mixed Matrix Membranes for Propane/Nitrogen Mixture Separation. SEPARATIONS 2022. [DOI: 10.3390/separations9030064] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In this study, zeolite molecular sieve SAPO-34/polydimethylsiloxane (PDMS) mixed matrix membranes (MMMs) were prepared to recover propane. n-Octyltrichlorosilane (OTCS) was introduced to improve compatibility between SAPO-34 and PDMS, and enhance the separation performance of the MMMs. Physicochemical properties of the MMMs were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and water contact angle (WCA). Results showed that, after modification, alkyl chains were successfully grafted onto SAPO-34 without changing its crystal structure, particles in the MMMs were evenly distributed in the base film, and the hydrophobicity of the MMMs was enhanced. Moreover, the effects of SAPO-34 filling content, operating pressure, and feed gas concentration on the separation performance was explored. This indicated that the modification with OTCS effectively enhanced the separation performance of SAPO-34/PDMS MMMs. When the filling content of modified SAPO-34 was 15%, the maximal separation factor of 22.1 was achieved, and the corresponding propane permeation rate was 101 GPU.
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