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<bill bill-stage="Introduced-in-Senate" dms-id="A1" public-private="public" slc-id="S1-MAZ26343-SRW-2J-47M"><metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
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<dc:title>119 S4571 IS: Tropospheric Ozone Research Act of 2026</dc:title>
<dc:publisher>U.S. Senate</dc:publisher>
<dc:date>2026-05-19</dc:date>
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<dc:language>EN</dc:language>
<dc:rights>Pursuant to Title 17 Section 105 of the United States Code, this file is not subject to copyright protection and is in the public domain.</dc:rights>
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<distribution-code display="yes">II</distribution-code><congress>119th CONGRESS</congress><session>2d Session</session><legis-num>S. 4571</legis-num><current-chamber>IN THE SENATE OF THE UNITED STATES</current-chamber><action><action-date date="20260519">May 19, 2026</action-date><action-desc><sponsor name-id="S316">Mr. Whitehouse</sponsor> (for himself and <cosponsor name-id="S353">Mr. Schatz</cosponsor>) introduced the following bill; which was read twice and referred to the <committee-name committee-id="SSEV00">Committee on Environment and Public Works</committee-name></action-desc></action><legis-type>A BILL</legis-type><official-title>To require the Environmental Protection Agency to establish a tropospheric ozone research program, and for other purposes.</official-title></form><legis-body><section id="S1" section-type="section-one"><enum>1.</enum><header>Short title</header><text display-inline="no-display-inline">This Act may be cited as the <quote><short-title>Tropospheric Ozone Research Act of 2026</short-title></quote>.</text></section><section commented="no" display-inline="no-display-inline" id="idf9f99a17fcf24919abeb88ff554b4a86"><enum>2.</enum><header>Tropospheric ozone research program</header><subsection id="id4d107a3eeeeb46228844b18bda6ea9ce"><enum>(a)</enum><header>Definitions</header><text>In this section:</text><paragraph commented="no" display-inline="no-display-inline" id="id4c32e432234e4a5da617b609c3398fe1"><enum>(1)</enum><header>Administrator</header><text>The term <term>Administrator</term> means the Administrator of the Environmental Protection Agency.</text></paragraph><paragraph commented="no" display-inline="no-display-inline" id="idd0e136cf16504c3186ddf67354a66655"><enum>(2)</enum><header>Program</header><text>The term <term>program</term> means the grant program established under subsection (b).</text></paragraph><paragraph commented="no" display-inline="no-display-inline" id="idba3d01874f77462b9cf0e732ff8d28de"><enum>(3)</enum><header>Tropospheric ozone</header><text>The term <term>tropospheric ozone</term> means ozone found within the Earth's troposphere.</text></paragraph><paragraph commented="no" display-inline="no-display-inline" id="id08053030fe274fba8e09687a47dfae51"><enum>(4)</enum><header>Tropospheric ozone precursor</header><text>The term <term>tropospheric ozone precursor</term> means any of methane, nitrogen oxides, carbon monoxide, nonmethane volatile organic compounds, and other compounds that react to form tropospheric ozone.</text></paragraph></subsection><subsection commented="no" display-inline="no-display-inline" id="id47422b3abbd64ffcb466e8d07b93b96f"><enum>(b)</enum><header>Establishment</header><text>Not later than 90 days after the date on which amounts are appropriated to carry out this Act, the Administrator shall establish a competitive grant program to award grants to eligible entities to carry out research with respect to the climate impacts of tropospheric ozone.</text></subsection><subsection commented="no" display-inline="no-display-inline" id="id65acf1effc62421b913fe9fff21dd9ef"><enum>(c)</enum><header>Research topics</header><paragraph commented="no" display-inline="no-display-inline" id="id3c759df8ebfb42f592f3485093d173fc"><enum>(1)</enum><header>In general</header><text display-inline="yes-display-inline">The research carried out using grants under the program shall include research with respect to—</text><subparagraph commented="no" display-inline="no-display-inline" id="id5e2d3b0ac01741ea9bdf8959b0d0e38f"><enum>(A)</enum><text>improving understanding of the impact of tropospheric ozone concentrations and mitigation on global temperatures, including—</text><clause commented="no" display-inline="no-display-inline" id="id873f0d16eefb482984367ea806ebb2f3"><enum>(i)</enum><text display-inline="yes-display-inline">the role of regional or localized tropospheric ozone concentrations;</text></clause><clause commented="no" display-inline="no-display-inline" id="idf3747aa87b7845d4b7b630412bb9ebea"><enum>(ii)</enum><text display-inline="yes-display-inline">the role of emission or mitigation of specific tropospheric ozone precursors; and</text></clause><clause commented="no" display-inline="no-display-inline" id="idee8b906fc9ca47f7b1389b4ad9f2fdf4"><enum>(iii)</enum><text display-inline="yes-display-inline">interactions with other atmospheric pollutants (such as particulate matter);</text></clause></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="idc8a1c2943b614714ba15baac3d89912d"><enum>(B)</enum><text>improving understanding of the impact of tropospheric ozone concentrations and mitigation on regional, localized, and seasonal temperatures and heat stress, including—</text><clause commented="no" display-inline="no-display-inline" id="idf29a8b02c7d2486aa551647b1231b355"><enum>(i)</enum><text display-inline="yes-display-inline">the role of regional or localized tropospheric ozone concentrations;</text></clause><clause commented="no" display-inline="no-display-inline" id="id67863c6e71cc4a8da0aaeb2e3edf84e1"><enum>(ii)</enum><text display-inline="yes-display-inline">the role of emission or mitigation of specific tropospheric ozone precursors; and</text></clause><clause id="id5aeb42054e8d4bc39f67697730b730f7" commented="no" display-inline="no-display-inline"><enum>(iii)</enum><text display-inline="yes-display-inline">interactions with other atmospheric pollutants (such as particulate matter);</text></clause></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="idb738bf9bc1c74cc2962e0087676cf2be"><enum>(C)</enum><text>improving understanding of natural interactions affecting tropospheric ozone concentrations and mitigation, such as nonanthropogenic tropospheric ozone precursor emissions, stratospheric ozone, and lightning;</text></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="idc45a71d2301b4f9b84b1bd1d15765d7b"><enum>(D)</enum><text>improving understanding of crop loss impacts from elevated levels of tropospheric ozone, including regional and local impacts and potential measures to reduce crop loss impacts;</text></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="id080412453eae4ead80d65a1bc3ff56a4"><enum>(E)</enum><text>improving understanding of forest and ecosystem productivity impacts from elevated levels of tropospheric ozone, including regional and local impacts;</text></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="id49617d6170f64816ae81d229b217d34c"><enum>(F)</enum><text>developing or updating existing regional and global climate models or other relevant models to better incorporate the radiative forcing and temperature impacts of tropospheric ozone and the interactions between tropospheric ozone and other greenhouse gases and air pollutants; and</text></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="idff461eda73604dce86dc5efc8d25da89"><enum>(G)</enum><text>subject to paragraph (3), strengthening and expanding tropospheric ozone and tropospheric ozone precursor monitoring and observational infrastructure, including—</text><clause commented="no" display-inline="no-display-inline" id="id0d9913a69ba44fbc8e31e88f0bf21977"><enum>(i)</enum><text display-inline="yes-display-inline">enhancement of ground-based monitoring networks (with increased coverage in rural, agricultural, and other understudied regions);</text></clause><clause commented="no" display-inline="no-display-inline" id="ideec75d4e6b144c6eb4f93677b51c7135"><enum>(ii)</enum><text display-inline="yes-display-inline">integration of surface observations with satellite remote sensing and chemical transport model outputs;</text></clause><clause commented="no" display-inline="no-display-inline" id="id19d738e6592748b5af41a1f7b55178d8"><enum>(iii)</enum><text display-inline="yes-display-inline">expanded vertical profiling through ozonesondes and aircraft measurements, particularly in understudied regions; and</text></clause><clause commented="no" display-inline="no-display-inline" id="id1fde1e7afb1847e59b21b44505492fb5"><enum>(iv)</enum><text display-inline="yes-display-inline">development of standardized data assimilation frameworks to support climate and air quality monitoring.</text></clause></subparagraph></paragraph><paragraph commented="no" display-inline="no-display-inline" id="id4706fee13f294cbda1aabbf972d07cf3"><enum>(2)</enum><header>Current and future modeling</header><subparagraph commented="no" display-inline="no-display-inline" id="id21536a4031ee4bbc8fb1ce349e08349c"><enum>(A)</enum><header>In general</header><text display-inline="yes-display-inline">In seeking to carry out the research described in subparagraphs (A) through (F) of paragraph (1), the Administrator shall seek to include research that—</text><clause commented="no" display-inline="no-display-inline" id="idbe7029ec6417446cba548b5d6fee2f5e"><enum>(i)</enum><text display-inline="yes-display-inline">assesses tropospheric ozone impacts and interactions at concentrations present on the date the program is established; and</text></clause><clause commented="no" display-inline="no-display-inline" id="id569737e66d9b45b8a92349efd6ea3530"><enum>(ii)</enum><text display-inline="yes-display-inline">models future tropospheric ozone concentrations, impacts, and interactions.</text></clause></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="idaa0b32c74f2e44a4a9caaf82d055e8bf"><enum>(B)</enum><header>Future tropospheric ozone</header><text>In seeking to carry out research with respect to the future tropospheric ozone concentrations, impacts, and interactions described in subparagraph (A)(ii), the Administrator shall seek to carry out research that—</text><clause commented="no" display-inline="no-display-inline" id="id3149c8d0a9634498aa50e741a8dbd2fd"><enum>(i)</enum><text display-inline="yes-display-inline">models a range of scenarios, including scenarios that assume that trends in emissions of tropospheric ozone precursors, other atmospheric pollutants, and greenhouse gases in effect on the date on which the program is established continue and scenarios that assume reductions in such emissions; and</text></clause><clause commented="no" display-inline="no-display-inline" id="id1a75ab38702d4761976a04ebf9ce4e5e"><enum>(ii)</enum><text>includes an assessment of how climate impacts (such as increased wildfires, increased temperatures, altered atmospheric circulation patterns, and changes in humidity, stagnation frequency, and lightning frequency) or changes in other atmospheric pollutants across the modeled range of scenarios affect tropospheric ozone concentrations, and related impacts.</text></clause></subparagraph></paragraph><paragraph commented="no" display-inline="no-display-inline" id="idfd4dad2f28c64e03b93acb6596918b5f"><enum>(3)</enum><header>Public availability of data</header><text>The Administrator shall ensure that any data collected pursuant to paragraph (1)(G) is made publicly available.</text></paragraph></subsection><subsection id="ida42c2f204cb74f1582dd38d17e4458c0"><enum>(d)</enum><header>Eligible entities</header><text>An entity eligible to receive a grant under the program is—</text><paragraph commented="no" display-inline="no-display-inline" id="id15a17c3d5502407bb85d9247f39765a1"><enum>(1)</enum><text>an institution of higher education;</text></paragraph><paragraph commented="no" display-inline="no-display-inline" id="idc1771dd86543457a990d7fc3de465500"><enum>(2)</enum><text>a National Laboratory (as defined in section 2 of the Energy Policy Act of 2005 (<external-xref legal-doc="usc" parsable-cite="usc/42/15801">42 U.S.C. 15801</external-xref>)); or</text></paragraph><paragraph commented="no" display-inline="no-display-inline" id="idb7c11cfc6e94403aa97f5619f2d437c7"><enum>(3)</enum><text>any other nonprofit research entity with demonstrated expertise in atmospheric chemistry, weather modeling, climate modeling, or air quality monitoring.</text></paragraph></subsection><subsection id="id5f5663455c16487d97fcf872c62e0652" commented="no"><enum>(e)</enum><header>Applications</header><text>An eligible entity seeking a grant under the program shall submit to the Administrator an application at such time, in such manner, and containing such information as the Administrator may require.</text></subsection><subsection commented="no" display-inline="no-display-inline" id="id9abc5ebf82094abf8495fd707ad66795"><enum>(f)</enum><header>Timing</header><text display-inline="yes-display-inline">The Administrator shall select recipients of grants under the program not later than 180 days after the date on which the program is established.</text></subsection><subsection commented="no" display-inline="no-display-inline" id="id91801020e4bd4cc0bbbcff82976077bb"><enum>(g)</enum><header>Collaboration</header><text>In carrying out the program, the Administrator shall collaborate with the international scientific community on science, research, and data-sharing with respect to the research topics described in subsection (c)(1), including through multilateral forums.</text></subsection><subsection commented="no" display-inline="no-display-inline" id="ide85e904397e44f3ea8e35d7d9615c2c7"><enum>(h)</enum><header>Reports</header><paragraph commented="no" display-inline="no-display-inline" id="id41d1eeb272024271989401f6e4cd1723"><enum>(1)</enum><header display-inline="yes-display-inline">Reports to Administrator</header><subparagraph commented="no" display-inline="no-display-inline" id="id21758b79fd794ba8b1e4407a07a5e313"><enum>(A)</enum><header>In general</header><text display-inline="yes-display-inline">The recipient of a grant under the program shall annually submit to the Administrator a report describing the findings of the recipient with respect to the research for which the grant was provided.</text></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="id73f18d63cecc4703887adb99d4c0de53"><enum>(B)</enum><header>Public availability</header><text display-inline="yes-display-inline">A report submitted under subparagraph (A) shall be made publicly available.</text></subparagraph></paragraph><paragraph commented="no" display-inline="no-display-inline" id="id18794d02fcbe43b1a5107513d8133ffe"><enum>(2)</enum><header>EPA report</header><text display-inline="yes-display-inline">Not later than 4 years after the date on which the program is established, the Administrator shall submit to the Committee on Environment and Public Works of the Senate and the Committee on Energy and Commerce of the House of Representatives and make publicly available a report that describes the findings and recommendations of the Administrator with respect to the program and tropospheric ozone, which shall include—</text><subparagraph commented="no" display-inline="no-display-inline" id="id072d8dbaeb5041308f18efb2729cc362"><enum>(A)</enum><text>a description of the contributions of tropospheric ozone at concentrations in effect on the date the report is submitted to—</text><clause commented="no" display-inline="no-display-inline" id="id58192062911e452394d5e3dd5206c408"><enum>(i)</enum><text>global temperature rise;</text></clause><clause commented="no" display-inline="no-display-inline" id="id0e09fb78a3ca422c8007a31cf212716b"><enum>(ii)</enum><text>regional, localized, and seasonal warming and heat stress;</text></clause><clause commented="no" display-inline="no-display-inline" id="id522802ef74fe440d9769afedc34e1084"><enum>(iii)</enum><text>crop losses and forest and ecosystem productivity impacts; and</text></clause><clause commented="no" display-inline="no-display-inline" id="ide6bc7bfeeac64782b7ca4c815234c620"><enum>(iv)</enum><text>health effects;</text></clause></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="ided595c377b064f2c831136e152ab75f3"><enum>(B)</enum><text>the forecasted future contributions, under a range of scenarios, including scenarios that assume trends in emissions of tropospheric ozone precursors, other atmospheric pollutants, and greenhouses gases in effect on the date the report is submitted continue and scenarios that assume reductions in such emissions, of tropospheric ozone to—</text><clause commented="no" display-inline="no-display-inline" id="id70e798bf7f8744c694af3c709af99fec"><enum>(i)</enum><text>global temperature rise;</text></clause><clause commented="no" display-inline="no-display-inline" id="id4d61cc475c934a4fb7903c206347cd6e"><enum>(ii)</enum><text>regional, localized, and seasonal warming and heat stress;</text></clause><clause commented="no" display-inline="no-display-inline" id="idf5f90c2a66704292b19dff315737a264"><enum>(iii)</enum><text>crop losses and forest and ecosystem productivity impacts; and</text></clause><clause id="idde626bd234db4f65a6ee3e8502ec7490" commented="no" display-inline="no-display-inline"><enum>(iv)</enum><text>health effects;</text></clause></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="id8b0c96ff50014a04b2881c2e706dde4c"><enum>(C)</enum><text display-inline="yes-display-inline">a description of the national or, as appropriate, regional, local, or seasonal options to mitigate specific tropospheric ozone precursors—</text><clause commented="no" display-inline="no-display-inline" id="id2a2d67ddcc804c04b30159b953431f2c"><enum>(i)</enum><text display-inline="yes-display-inline">to maximize global and localized warming reductions;</text></clause><clause commented="no" display-inline="no-display-inline" id="idaa946da360684503a685ca3b711a05f1"><enum>(ii)</enum><text>to minimize adverse impacts to health, forests, or ecosystems; and</text></clause><clause commented="no" display-inline="no-display-inline" id="ida1a5821f92784615a137d4d8c9d41195"><enum>(iii)</enum><text>to minimize crop loss impacts;</text></clause></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="idb6cb178059ce4d6e848cd2e6d6602df1"><enum>(D)</enum><text>a high-level assessment of the costs and benefits of tropospheric ozone precursor mitigation options identified under subparagraph (C); and</text></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="id582ac4b361b8403dbd2cf780c7f54e38"><enum>(E)</enum><text>policy recommendations for—</text><clause id="id512a161947a24a72af3d8e40433de519"><enum>(i)</enum><text>mitigation strategies for specific tropospheric precursors to minimize the negative impacts of tropospheric ozone, based on the findings described subparagraphs (C) and (D);</text></clause><clause commented="no" display-inline="no-display-inline" id="id49550febdf9a4f65a1dde9cd21245b7b"><enum>(ii)</enum><text>improvements in data collection and reporting for tropospheric ozone and tropospheric ozone precursors; and</text></clause><clause commented="no" display-inline="no-display-inline" id="id523fb048768041e1b942fa43babfa16f"><enum>(iii)</enum><text>further research needs.</text></clause></subparagraph></paragraph></subsection><subsection commented="no" display-inline="no-display-inline" id="id0b542f5780a240d4863950018b7f1a98"><enum>(i)</enum><header>Authorization of appropriations</header><paragraph commented="no" display-inline="no-display-inline" id="id8d4ad8003dec4221b6e5b156c536ad71"><enum>(1)</enum><header>In general</header><text>There are authorized to be appropriated to the Administrator to carry out the program—</text><subparagraph commented="no" display-inline="no-display-inline" id="idd68f2faf54c146e9839886e462095065"><enum>(A)</enum><text>$10,500,000 for each of fiscal years 2027 through 2029; and</text></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="id972761c3edb04710a3d7ef3163822f02"><enum>(B)</enum><text>$1,000,000 for fiscal year 2030.</text></subparagraph></paragraph><paragraph commented="no" display-inline="no-display-inline" id="idcf248ca4753246dca625f6698e5892d9"><enum>(2)</enum><header>Requirements</header><text>Of the amounts made available under paragraph (1)—</text><subparagraph id="ida4ad461418ac4bd39372836b43d8521b"><enum>(A)</enum><text>with respect to the amounts made available under subparagraph (A) of that paragraph—</text><clause commented="no" display-inline="no-display-inline" id="id5932118a958c46b38bd750f3654dbcc3"><enum>(i)</enum><text display-inline="yes-display-inline">$10,000,000 shall be used to make grants under the program; and</text></clause><clause id="id0aac505c3df04a40b62a7a13305475b5" commented="no" display-inline="no-display-inline"><enum>(ii)</enum><text>$500,000 shall be used to implement and oversee the program; and</text></clause></subparagraph><subparagraph commented="no" display-inline="no-display-inline" id="id4241d0b18d1d43d7a96287d6b65b0d97"><enum>(B)</enum><text>the amounts made available under subparagraph (B) of that paragraph shall be used to prepare the report required under subsection (h)(2).</text></subparagraph></paragraph></subsection></section></legis-body></bill>

