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  • Where can I download hourly emissions data from continuous monitoring?

    Hourly emissions data files are available from the Clean Air Markets Division of EPA, collected as part of 40 CFR Part 75. The download location has changed in February, 2023. The new location is https://campd.epa.gov/data/bulk-data-files . Once on this new site, use the menu (at the left) and the Keyword…

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  • Where can I find older NEI data (prior to 2008)?

    The raw data and summaries that are still available (dating back to 1990) can be obtained from the web page https://www.epa.gov/air-emissions-inventories/pollutant-emissions-summary-files-earlier-neis . Starting with 2001 data, a more limited selection of summary files are available.

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  • CFAT Impacts on EPCRA and RMP

    The Department of Homeland Security’s Chemical Facility Anti-Terrorism Standards (CFATS) impose comprehensive federal security regulations for high-risk chemical facilities. Do the CFATS alter the requirements that apply to a facility covered under both CFATS and either the Emergency Planning and Community Right-to-Know Act (EPCRA) or the Clean Air Act section…

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  • EPCRA Reporting Mechanisms for Protecting Sensitive Business Information

    Does EPCRA provide any mechanisms for facilities that must submit Tier II inventory information to protect sensitive business information? Trade secret and confidential location information (CLI) are two separate confidentiality provisions under EPCRA. Trade secret claims made under EPCRA Sections 303, 311, 312, or 313 allow facilities to claim the…

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  • How do the different parts of particulate matter (PM) fit together?

    The various parts of PM in the NEI are related as follows. PM10-FIL > PM25-FIL because PM10-FIL includes PM25-FIL PM25-PRI = PM25-FIL + PM-CON This equation only applies at the process level. Because some sources only can report PM2.5 (due to test method differences), this equation does not apply to…

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  • How does PM2.5 relate to PM species such as EC, OC, SO4, NO3, PMFINE, and DIESEL-PM25?

    Primary PM2.5 estimates are speciated into the five PM species in the NEI: elemental (black) carbon (EC), organic carbon (OC), nitrate (NO3), sulfate (SO4), and the remainder of PM25-PRI (PMFINE). Diesel engine PM25-PRI and PM10 emissions are also labeled as DIESEL-PM25 and DIESEL-PM10 for mobile source diesel engines. For all…

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  • How complete are the data in the National Emissions Inventory?

    While the goal of the National Emissions Inventory (NEI) program is to include all emissions data, there are always challenges meeting this goal. The answer about completeness of coverage of sources depends on the emissions sector and pollutant. In general, the criteria air pollutants and precursors (CAPs) are expected to…

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  • Where is more information available about emissions estimation methods used by the EPA?

    For criteria air pollutants and precursors as well as for hazardous air pollutants, the methods are described in the technical support document (TSD) for the latest National Emissions Inventory (NEI) available from the main NEI page . For greenhouse gas emissions, you can find greenhouse gas inventory methods from the…

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  • Tier2 Submit software and confidential chemical location information

    When using EPA’s Tier2 Submit software to comply with the annual Hazardous Chemical Inventory reporting requirement under the Emergency Planning and Community Right-to-Know Act (EPCRA) §312, how can a person withhold confidential chemical location information from disclosure to the public? In order to fulfill the proper reporting under EPCRA, a…

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  • Do states require extra Tier II information?

    Do states require additional information on the Tier II report? How can I find out about the state data requirements? Some states do want additional Tier II information; contact your state Tier II administrator to learn specific details. Tier2 Submit includes fields for the additional information requested or required by…

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  • No Street Address Availability Tier II Reporting

    Pursuant to 40 CFR 370.42(d) , Tier II chemical inventory information must include the complete name and address of the location of the facility (including the full street address or state road, city, county, State and zip code), latitude and longitude. If a facility does not have a street address…

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  • Are landfills covered under Title III of SARA since they are covered by RCRA?

    Yes, landfills are subject to certain Title III requirements. Subtitle A of Title III is intended to identify facilities which present a potential hazard for a chemical emergency and to provide a process for local emergency planning committees to engage with such facilities in determining the significance of the release…

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  • What sources make up the Tier 1 categories used in the emissions trends?

    Tier 1 categories are assigned by source classification codes (SCCs) that are the most specific processes available in the NEI. The latest SCC list with the Tier 1 assignments can be downloaded from the EPA SCC website in Comma Separate Values (CSV) format.

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  • What is the cause of the large decrease in electric utility emissions, particularly sulfur dioxide, starting in 1995?

    SO2 emissions reductions from utilities during this time are primarily attributed to the impacts of the acid rain program. As described on EPA’s Acid Rain Program web page, Phase 1 of this program began in 1995 and affected 263 units at 110 most coal-burning electric utility plants in 21 eastern…

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  • Are mobile boosters eligible for the transportation exemption?

    An oil company owns many wells on an oil field. Each well is on its own plot of land. These plots are not adjacent or contiguous and, therefore, each well is its own facility. When operating these wells, it is sometimes necessary to inject air or gas into the well…

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