13.6 Emissions Summaries

13.6.1 Wildland Fires

This section shows several graphics and tables that describe emissions of wild and prescribed fires in the 2023 NEI based on the methods discussed above. Table 13.14 provides national totals of acres burned and CAPs emissions for wildfires, prescribed burns and pile burns. Pile burns are part of the prescribed burn category but are show separately here since it is a new method for the 2023 NEI. Activity and emissions of prescribed fires identified only from HMS satellite data are shown as a percentage of the total prescribed fire values.

Table 13.14: National wildland fire acres burned and emissions for the 2023 NEI

Pollutant	2023NEI Wildfires	2023NEI Prescribed burns (no pile burns)	% Prescribed from HMS-Only	2023NEI Pile burns	Total Wildland
ACRES BURNED	2,911,888	13,181,343	42.0%	–	16,093,231
PM2.5 (tons)	884,537	1,126,551	41.0%	29,123	2,040,211
VOC (tons)	2,371,088	1,810,376	41.0%	3,433	4,184,897
NOX (tons)	68,017	121,462	38.0%	7,690	197,169
CO (tons)	6,789,077	7,804,179	41.0%	224,516	14,817,773
SO2 (tons)	49,961	78,207	42.0%	381	128,549
NH3 (tons)	65,260	68,369	44.0%	1,532	135,161

Table 13.15 provides national totals for burned acres and CAPs for each forest/ecoregion and fire type. The newly added SCCs allow for further analyses like this table. As mentioned earlier in the year 2023 was a very quiet wildfire season. It is unusual for the prescribed burns PM_2.5 emissions to be higher than wildfire emissions but this case can occur during very quiet wildfire seasons. Most of the Boreal Forest emissions occurred in Alaska. Note grassland acres burned make up a good portion of the acres burned for the US but grasses have a lower PM_2.5 emissions factor. Figure 13.5 provides an illustration of just the PM_2.5 emissions nationally and by forest/ecoregion for year 2023.

Table 13.15: Wildland fire acres burned and emissions for the 2023 NEI by forest/ecoregion.

SCC Ecoregion	Acres	PM2.5	VOC	CO	NOx	SO2	NH3
Eastem Forest Prescribed Burning	5,492,380	600,639	764,156	4,024,217	74,348	36,862	25,461
Western Forest Wildfires	960,708	366,068	862,274	2,713,692	25,629	26,709	27,555
Boreal Forest Wildfires	295,253	335,318	1,202,892	2,812,756	22,159	10,736	26,215
Grassland Prescribed Burning	4,785,192	290,207	536,545	2,114,821	23,004	26,356	26,468
Western Forest Prescribed Burning	1,518,351	162,316	316,485	1,152,784	13,733	10,910	10,549
Eastern Forest Wildfires	530,066	114,006	151,673	766,339	14,253	7,181	4,922
Grassland Wildfires	757,901	45,053	82,867	321,715	3,544	3,850	3,943
Boreal Forest Prescribed Burning	105,746	39,394	128,338	318,077	2,703	1,210	3,037
Shrubland Wildfires	367,960	24,093	71,382	174,576	2,432	1,485	2,624
Flint Hills Prescribed Burning	1,114,770	22,828	38,932	115,655	6,355	2,268	1,638
Shrubland Prescribed Burning	164,903	11,168	25,920	78,625	1,319	601	1,216

Figure 13.5: 2023 NEI PM_2.5 emissions by forest/ecoregion and fire type category

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Figures 13.6 and 13.7 show acres burned and PM_2.5 emissions for all fires by month in 2023. The total emissions that result from month-to-month result from a combination of different fuels that burn in different fires. It is seen that wildfires (WF) are more prevalent in the hotter months, and prescribed fires (RX) occur more often in the cooler months of 2023. Flint Hills prescribed burns are show separately to mark when those occurred over eastern Kansas and Oklahoma. Pile burns (PB) emissions are also shown but are very minor in most months.

Figure 13.6: Monthly acres burned by fire type for 2023 NEI CONUS Wildland Fires

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Figure 13.7: Monthly PM_2.5 by fire type for 2023 NEI CONUS Wildland Fires

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Next, Table 13.16 shows a summary of acres burned and PM_2.5 by state, fire type and combustion phase. In terms of total WLF acres burned, several states are shown to have more than one million acres burned in 2023, with FL, GA, KS and TX being the highest acres burned states. However, due to the nature of fuels burned and the type of fire that occurs in the various States, AK and OR are highest for estimated PM_2.5 emissions.

Table 13.16: Summary of acres burned and PM_2.5 emissions by state and fire type

State	Prescribed burns acres burned	% Prescribed fire acres from HMS-Only	Prescribed burns PM2.5 (tons)	% Prescribed fire PM2.5 from HMS-Only	Wildfires acres burned	Wildfires PM2.5 (tons)	Total Wildland fire acres burned	Total Wildland fire PM2.5 (tons)
AL	806,372	0.0%	64,127	0.0%	4,980	871	811,352	64,998
AK	17,223	0.0%	14,615	4.2%	296,751	336,654	313,974	351,269
AZ	237,971	6.2%	17,056	7.2%	214,436	14,455	452,407	31,511
AR	520,289	44.6%	74,454	35.2%	15,748	3,607	536,037	78,061
CA	150,734	0.0%	25,702	0.0%	376,952	116,250	527,686	141,953
CO	53,893	45.8%	4,955	38.2%	47,194	8,429	101,086	13,384
CT	1,118	83.7%	158	91.9%	321	80	1,438	238
DE	1,909	65.4%	218	78.5%	–	–	1,909	218
DC	–	0.0%	–	0.0%	8	3	8	3
FL	1,565,478	0.0%	137,813	0.0%	102,035	10,052	1,667,513	147,865
GA	1,241,104	0.0%	96,029	0.0%	17,236	2,382	1,258,339	98,411
HI	580	74.0%	54	72.3%	13,297	1,322	13,877	1,376
ID	72,627	41.9%	12,009	39.4%	104,523	25,278	177,150	37,287
IL	185,894	86.0%	13,585	76.2%	108	12	186,002	13,597
IN	65,815	82.3%	6,899	82.1%	597	102	66,411	7,001
IA	213,009	87.3%	12,656	75.1%	23,161	1,654	236,170	14,311
KS	1,481,127	27.5%	43,261	49.0%	6,035	260	1,487,162	43,521
KY	151,625	89.5%	18,780	82.3%	43,915	14,199	195,540	32,979
LA	698,543	77.4%	73,607	75.9%	172,194	18,922	870,737	92,530
ME	2,090	94.2%	345	92.2%	307	62	2,397	407
MD	24,920	51.4%	2,367	52.2%	1,460	207	26,380	2,574
MA	3,375	49.7%	434	50.4%	1,038	268	4,414	702
MI	24,926	81.0%	2,454	75.7%	4,071	924	28,997	3,378
MN	150,995	61.7%	14,687	63.1%	7,214	2,395	158,209	17,082
MS	413,569	0.0%	32,426	0.0%	27,694	2,888	441,263	35,313
MO	658,573	88.8%	79,396	83.0%	20,846	5,020	679,420	84,416
MT	86,362	49.2%	9,919	35.9%	112,404	29,025	198,765	38,944
NE	187,934	95.2%	10,079	94.1%	59,876	5,290	247,810	15,369
NV	12,625	35.7%	256	42.5%	4,844	72	17,469	328
NH	950	76.4%	128	78.8%	43	11	994	139
NJ	26,758	15.4%	6,377	23.3%	17,657	11,739	44,414	18,116
NM	172,902	15.4%	9,808	7.9%	200,081	20,181	372,984	29,988
NY	21,304	96.0%	2,942	94.9%	1,166	318	22,470	3,260
NC	189,832	0.0%	17,901	0.0%	90,035	17,994	279,867	35,895
ND	62,047	80.2%	2,113	77.9%	7,956	261	70,003	2,374
OH	49,263	89.5%	5,029	87.9%	770	185	50,034	5,214
OK	731,471	87.0%	53,451	88.4%	133,808	17,355	865,279	70,806
OR	53,051	0.0%	24,004	0.0%	224,305	129,372	277,356	153,376
PA	60,280	76.9%	7,187	74.2%	9,914	2,675	70,194	9,862
RI	663	100.0%	101	100.0%	465	99	1,128	200
SC	411,521	0.0%	32,656	0.0%	6,339	854	417,860	33,511
SD	65,773	73.2%	3,073	66.9%	1,662	33	67,435	3,106
TN	251,609	85.1%	33,795	81.5%	18,346	5,563	269,955	39,358
TX	1,647,666	88.3%	109,636	80.4%	223,948	14,414	1,871,614	124,050
UT	41,367	37.2%	4,437	27.4%	27,601	3,985	68,968	8,422
VT	1,950	78.0%	246	72.2%	12	4	1,963	250
VA	153,265	81.7%	17,141	79.1%	31,558	8,989	184,823	26,130
WA	10,964	0.0%	680	0.0%	167,917	32,574	178,881	33,254
WV	59,695	97.7%	10,621	97.8%	49,188	16,011	108,884	26,632
WI	87,971	84.0%	11,919	71.3%	4,352	769	92,324	12,689
WY	50,358	65.1%	4,965	60.3%	15,518	465	65,876	5,431
National Total	13,181,343	42.3%	1,126,551	41.1%	2,911,888	884,537	16,093,231	2,011,088

Figures 13.8 and 13.9 show 2023 county total area (acres) burned and PM_2.5 emissions for wildfires, respectively. Even though 2023 was a quiet wildfire season the western portion of the country had the higher emitting counties. Figures 13.10 and 13.11 show 2023 county total area (acres) burned and PM_2.5 emissions for prescribed burns, respectively. The Southeast states are seen to be dominated by prescribed fires. This is a typical pattern we see from NEI-to-NEI.

Figure 13.8: 2023 NEI wildland fires county area burned density map

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Figure 13.9: PM_2.5 county emissions for wildfires for 2023 NEI

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Figure 13.10: 2023 NEI prescribed burns acres burned density map

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Figure 13.11: PM_2.5 county emissions for prescribed burns for 2023 NEI

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The amount of fire activity acquired by EPA for the NEI effort continues to increase with each NEI. When Smartfire2 doesn’t have any national or S/L/T activity to reconcile with it, it is then labeled as a satellite-only detected fire or HMS-only detected fire. Due to the location and months of these HMS-only detected fires they are assigned the prescribed burn fire type. If the HMS-only detect occurs on agricultural lands it is assigned an agricultural burn SCC. Table 13.17 provides a summary of the total acres and emissions from these HMS-only detected fires by fire type. Note that about 40% of the acres burned and emissions for prescribed burns (RX) are from HMS-only detected fires. In previous NEIs, this percentage approached or exceeded 50%. In future NEIs, if even more prescribed fire activity data is provided this percentage should continue to be reduced. The wildfire activity is much more complete thanks to national attention and detailed datasets. The HMS-only detects in summer months in western states are assumed to be wildfires and this only adds up to about 7% of the total wildfire acres burned and about 3% of the total emissions.

Table 13.17: Summary of acres burned and emissions by fire type for satellite-detected (HMS) only fires versus all fires totals

Fire Type Description	Acres Burned	PM2.5	VOC	CO	NOx	SO2	NH3
Total RX	13,181,343	1,126,551	1,810,376	7,804,179	121,462	78,207	68,369
HMS only RX	5,582,767	463,476	742,355	3,204,575	46,615	33,167	29,847
HMS % of Total RX	42.4%	41.1%	41.0%	41.1%	38.4%	42.4%	43.7%
Total WF	2,911,888	884,537	2,371,088	6,789,077	68,017	49,961	65,260
HMS only WF	219,343	22,591	53,190	155,985	1,981	1,478	1,753
HMS % of Total WF	7.5%	2.6%	2.2%	2.3%	2.9%	3.0%	2.7%

Figure 13.12 provides a county map of the total HMS-only acres burned for prescribed burns in the 2023 NEI. The map shows that most of the HMS-only acres burned are in the southern central parts of the US. These are areas where there is a lack of prescribed burn activity available for use in the NEI. Table 13.18 provides state totals of HMS-only acres burned versus total acres burned for prescribed burns. There are numerous states in the southern central part of the country that have HMS-only acres burned about 80+% of their total acres burned by prescribed burns.

Figure 13.12: Satellite-only (HMS) detected county acres burned for prescribed burns

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Table 13.18: Summary of acres burned by state for satellite-detected (HMS) only fires

State	HMS detect only acres	Total prescribed acres	% not reconciled with activity
Alabama	0.00	806372.20	0.0000000
Alaska	0.00	17223.08	0.0000000
Arizona	14739.73	237971.03	0.0619392
Arkansas	231971.26	520288.81	0.4458510
California	0.00	150734.48	0.0000000
Colorado	24707.12	53892.57	0.4584515
Connecticut	936.00	1117.63	0.8374865
Delaware	1248.00	1909.03	0.6537351
Florida	0.00	1565478.43	0.0000000
Georgia	0.00	1241103.86	0.0000000
Hawaii	429.00	579.89	0.7397955
Idaho	30442.00	72627.49	0.4191526
Illinois	159783.00	185893.57	0.8595402
Indiana	54171.00	65814.61	0.8230847
Iowa	185902.00	213009.31	0.8727412
Kansas	406804.00	1481126.88	0.2746584
Kentucky	135720.00	151624.90	0.8951037
Louisiana	540963.25	698543.43	0.7744161
Maine	1968.00	2090.00	0.9416268
Maryland	12809.25	24919.97	0.5140155
Massachusetts	1677.00	3375.16	0.4968653
Michigan	20188.45	24926.04	0.8099341
Minnesota	93185.00	150994.93	0.6171399
Mississippi	0.00	413569.02	0.0000000
Missouri	584610.00	658573.15	0.8876918
Montana	42451.00	86361.85	0.4915481
Nebraska	178973.00	187934.42	0.9523162
Nevada	4512.00	12624.95	0.3573876
New Hampshire	726.00	950.46	0.7638407
New Jersey	4125.00	26757.87	0.1541603
New Mexico	26608.60	172902.32	0.1538938
New York	20457.10	21303.65	0.9602627
North Carolina	0.00	189832.02	0.0000000
North Dakota	49758.00	62047.13	0.8019388
Ohio	44070.00	49263.43	0.8945784
Oklahoma	636133.75	731471.46	0.8696631
Oregon	0.00	53051.47	0.0000000
Pennsylvania	46325.50	60279.80	0.7685079
Rhode Island	663.00	663.00	1.0000000
South Carolina	0.00	411521.12	0.0000000
South Dakota	48133.00	65773.10	0.7318037
Tennessee	214176.00	251608.51	0.8512272
Texas	1454898.60	1647665.82	0.8830059
Utah	15384.00	41366.99	0.3718907
Vermont	1521.00	1950.18	0.7799280
Virginia	125175.25	153265.27	0.8167229
Washington	0.00	10964.12	0.0000000
West Virginia	58344.00	59695.35	0.9773625
Wisconsin	73860.00	87971.32	0.8395918
Wyoming	32775.00	50357.69	0.6508440
Total United States	5581323.87	13181342.76	0.4234260

13.6.2 Agricultural field burning

The NEI uses numerous SCC to classify agricultural burns. Table 13.19 provides a national summary by SCC for the EPA default 2023 NEI emissions. A total of about 54,500 tons of PM_2.5 are estimated to be emitted by this sector. Figure 13.13 provides a county map of agricultural burn PM_2.5 emissions for year 2023 using the EPA methodology. Note higher emissions are estimated for portions of southern Florida and parts of California and Washington. Figure 13.14 provides monthly PM_2.5 emissions for agricultural field burning in tons. Note emissions are smaller during the summer months with peaks in April, August and October. Table 13.20 lists the top ten states for PM_2.5 emissions with Florida being the state with highest emissions. Shown in Table 13.21: are comparisons of PM_2.5 emissions for those states that submitted PM_2.5 vs EPA estimates. Only a few S/L/Ts submitted emissions.

Table 13.19: National Agricultural burning PM_2.5 emissions by SCC for 2023 EPA default emissions

SCC	SCC Description	2023 EPA-default PM2.5 emissions (tons)
2801500000	Agricultural Field Burning; Unspecified crop type	14,738
2801500141	Agricultural Field Burning; Field Crop is Bean (red)	6,392
2801500150	Agricultural Field Burning; Field Crop is Corn	8,803
2801500151	Agricultural Field Burning; Double Crop Winter Wheat and Corn	46
2801500160	Agricultural Field Burning; Field Crop is Cotton	1,236
2801500171	Agricultural Field Burning; Fallow	2,891
2801500220	Agricultural Field Burning; Field Crop is Rice	2,250
2801500250	Agricultural Field Burning; Field Crop is Sugar Cane	1,882
2801500262	Agricultural Field Burning; Field Crop is Wheat	5,533
2801500263	Agricultural Field Burning; Double Crop Winter Wheat and Cotton	10
2801500264	Agricultural Field Burning; Double Crop Winter Wheat and Soybeans	1,345
2801540000	Agricultural Field Burning - Ditch Burning	1,508
2811020002	Rangeland Burning	7,928
TOTAL		54,562

Figure 13.13: 2023 NEI annual, county PM_2.5 emissions for crop residue burns

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Figure 13.14: 2023 NEI monthly PM_2.5 emissions (tons) for crop residue burns

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Table 13.20: Top ten states: 2023 EPA-default agricultural burning PM_2.5 emissions

State Name	PM2.5 (tons)
Florida	7,139
California	4,929
Washington	4,094
Arkansas	4,080
Louisiana	4,051
North Dakota	2,920
Nebraska	2,588
Texas	2,523
Georgia	2,251
Kansas	2,170

Table 13.21: Comparison of State vs EPA 2023 PM_2.5 emissions (tons) for agencies that submitted.

State/Tribe	S/L/T-submitted	EPA-default
Maricopa County, AZ	0	44
Idaho	1,038	907
New Jersey	50	20
Washington	3,056	4,094
Nez Perce	524	Not available