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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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  • 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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  • Obtaining an RMP ID Number

    How can a facility subject to the Risk Management Plan (RMP) requirements obtain its RMP ID number? The owner or operator of a regulated RMP facility that has already submitted an RMP, may obtain the facility's identification number (RMP ID Number) by contacting the RMP Reporting Center (703-227-7650). An RMP-covered…

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  • Does EPA have enforcement authority for the risk management program regulations?

    Yes. Under §113 of the CAA, the Agency has the authority to bring administrative and judicial actions against violators. Judicial actions can be civil and criminal in nature. Section 113(a)(3) authorizes the Agency to order violators to comply with the risk management program regulations. Under section 113(b), the Agency may…

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  • Criteria for selecting stationary sources to audit

    What criteria will be used to select stationary sources for periodic compliance audits of risk management plans (RMPs) submitted under 40 CFR Part 68, Subpart G? The implementing agency will, according to the regulations at 40 CFR §68.220(b), select stationary sources for audits based on any of the following criteria…

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  • Is there a citizen suit provision applicable to RMP?

    Is there a citizen suit provision applicable to CAA §112 and the risk management program rule? Yes, section 304 of the CAA includes a citizen suit provision for violations of emission standards or limitations promulgated under the Act.

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  • Accessing RMP Data

    Is Risk Management Plan (RMP) data available to the public and, if so, where can it be found? Risk Management Plans (RMPs) prepared and submitted pursuant to CAA section 112(r) are, by statute, available to the public. Members of the general public may obtain RMP data by visiting a designated…

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  • How may state and local rules be more stringent?

    In what ways may state and local rules be more stringent? Does this document ( General Risk Management Program Guidance ) provide guidance on state and local differences? States and localities may impose more detailed requirements, such as requiring more documentation or more frequent reporting, specifying hours of training or…

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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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  • 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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  • Statutory authority and regulatory source for the risk management program

    What is the statutory authority and the regulatory source for the risk management program regulations that are codified in 40 CFR Part 68? The risk management program regulations were promulgated pursuant to the §112(r) accidental release prevention provisions of the Clean Air Act, as amended in 1990. The regulatory sources…

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