Last reviewed on June 22, 2018

Short-Lived Climate Pollutant Inventory


Short-lived climate pollutants (SLCP) are warming compounds that stay in the atmosphere for a shorter period of time than carbon dioxide, including black carbon particles, methane, and some hydrofluorocarbon gases (HFC).

This page contains data and documentation for the short lived climate pollutant inventories and projections for methane, short-lived HFCs, and black carbon used in the SLCP Strategy. These inventories represent a snapshot of the best available data used at the time of SLCP Strategy development in 2015.

Methane Inventory

The methane inventory and projection is based on the 2015 edition of the ARB greenhouse emission inventory. A summary of inventory data and documentation are available below.

2013 CH4 Sources

Methane Data

Hydrofluorocarbon Inventory

Hydrofluorocarbons (HFC) constitute a class of fluorinated compounds with a wide range of lifetimes and global warming potentials (GWP). Many HFCs have short lifetimes thus are considered SLCPs. The HFC SLCP inventory includes nine short-lived HFCs from the 2015 Edition of California's official greenhouse gas emission inventory. These are: HFC-125, HFC-134a, HFC-143a, HFC-152a, HFC-227ea, HFC-245fa, HFC-32, HFC-365mfc, and HFC-43-10mee. The GWP and lifetime of each HFC is available on the GWP page.

A summary of inventory data and documentation of HFC emissions is available below.

2013 Short-Lived HFC Sources

Short-Lived HFC Data

Short-Lived HFC Inventory Documentation

Black Carbon Inventory

The California Air Resources Board has developed a statewide emission inventory for black carbon in support of the Short-Lived Climate Pollutant Strategy. The black carbon inventory uses elemental carbon (EC) speciation profiles developed by ARB as a proxy for black carbon. Speciation profiles are applied to PM2.5 mass emissions to estimate black carbon emissions.

A summary of inventory data and documentation of black carbon emissions is available below.

Non-Forestry Black Carbon Data (included in SLCP black carbon targets)

2013 Black Carbon Sources

Forestry Black Carbon Data

The forestry category includes non-agricultural prescribed burning and wildfire emissions. Emissions from these activities exhibit high year-to-year variability and large uncertainty in current and future emissions, and are not included in the SLCP black carbon reduction target. To provide a more representative view of emissions without large year-to-year variability driven by natural forces, forestry emissions are calculated as a ten year average.

Ten Year Average California Forestry Black Carbon Emissions

Source MMTCO2e (20-yr) MMTCO2e (100-yr)
Prescribed Burning 3.6 1.0
Wildfire 86.7 24.4

Black Carbon Inventory Documentation

Sulfuryl Fluoride

Sulfuryl fluoride (SO2F2) is a fluorinated gas with a lifetime of 36 years. It is used as a pesticide for building fumigation and post-harvest storage of commodities, but is not licensed for use in agricultural fields. Sulfuryl fluoride was believed to have a negligible GWP until 2009, when new research assigned a 100-year GWP of 4090 and a 20-year GWP of 6840. Because sulfuryl fluoride was not identified as a high-GWP gas at the time, it was not included as an AB 32 gas, and is not annually inventoried as a part of ARB's statewide GHG inventory.

The Department of Pesticide Regulation (DPR) tracks usage of sulfuryl fluoride. A summary of 2013 emissions based on DPR data is shown below. Usage for other years can be obtained from the DPR website.

2013 California Sulfuryl Fluoride Emissions

Source MMTCO2e (20-yr) MMTCO2e (100-yr)
Structural Fumigation 7.6 4.6
Post-Harvest Storage 1.4 0.8
Other Fumigation 0.3 0.2
Total Emissions* 9.4 5.6

* Totals may not add due to rounding

For general questions regarding California's Greenhouse Gas or Short Lived Climate Pollutant Emission Inventories, please contact: Anny Huang, Manager, Emission Inventory Analysis Section, Phone: (916) 323-8475