core_epamats__hourly_emissions
Return to SearchHourly time series of hourly emissions of mercury (Hg) and hydrogen chloride (HCl) from coal- and oil-fired power plants.
- Most-recent data:
2026
- Processing:
Data has been cleaned and organized into well-modeled tables that serve as building blocks for downstream wide tables and analyses.
- Source:
EPA MATS -- Mercury and Air Toxics Standards
- Primary key:
plant_id_epa, emissions_unit_id_epa, operating_datetime_utc
Usage Warnings
Not all IDs are present.
Contains information from multiple raw inputs.
Additional Details
The EPA Mercury and Air Toxics Standards (MATS) dataset provides detailed information on emissions of hazardous air pollutants, specifically mercury (Hg), hydrogen chloride (HCl), and hydrogen fluoride (HF), from coal- and oil-fired power plants in the United States. Established under the Clean Air Act, MATS requires affected units to install and operate continuous emissions monitoring systems (CEMS) to track pollutant output rates and mass emissions.
Only coal- and oil-fired units above a certain capacity threshold are required to comply with MATS, so not all plants that report to EIA have corresponding MATS monitoring data. The data covers roughly 2015 onward and is reported hourly.
MATS does not require reporting of hourly hydrogen fluoride (HF) emissions, and the four HF columns are entirely null throughout the raw data, so they are dropped from this table. Only the mercury (Hg) and hydrogen chloride (HCl) columns contain data.
Units in the MATS data are identified by their EPA emissions unit IDs, which may differ from EIA generator IDs. Use the core_epa__assn_eia_epacamd crosswalk to connect MATS emissions units to EIA plant IDs and generators.
Columns
The unique six-digit facility identification number, also called an ORISPL, assigned by the Energy Information Administration.
The ORISPL ID used by EPA to refer to the plant. Usually but not always the same as plant_id_eia.
Emissions (smokestack) unit monitored by EPA CEMS.
Date and time measurement began (UTC).
Year the data was reported in, used for partitioning EPA CEMS.
Two letter US state abbreviation.
Plant name as reported to the EPA.
Length of time interval measured.
Average power in megawatts delivered during time interval measured.
The energy contained in fuel burned, measured in million BTU.
Total steam pressure produced by a unit during the reported hour.
Mercury (Hg) output emissions rate.
Mercury (Hg) emissions per unit of heat content.
Mercury (Hg) emissions in pounds.
Identifies whether the reported value of mercury (Hg) emissions was measured, calculated, startup or shutdown, or unavailable.
Hydrogen chloride (HCl) output emissions rate.
Hydrogen chloride (HCl) emissions per unit of heat content.
Hydrogen chloride (HCl) emissions in pounds.
Identifies whether the reported value of hydrogen chloride (HCl) emissions was measured, calculated, startup or shutdown, or unavailable.
EPA-associated stack IDs for the emissions unit.
Primary fuel type burned by the unit.
Secondary fuel type burned by the unit.
Type of emissions unit (e.g. boiler, combustion turbine).
Type of sulfur dioxide (SO2) control technology installed.
Type of nitrogen oxide (NOx) control technology installed.
Type of particulate matter (PM) control technology installed.
Type of mercury (Hg) control technology installed.