EPA Air · by state

Air-emissions sources in Maryland

• 9,831Facilities

By emissions classification in Maryland

• Major source
• Minor source
• Synthetic minor source

High-priority violations in Maryland

20 sources in Maryland carry a current high-priority Clean Air Act violation.

Counties in Maryland

• Allegany County 126
• Anne Arundel County 672
• Baltimore County 1,116
• Baltimore (city) County 1,788
• Calvert County 70
• Caroline County 44
• Carroll County 224
• Cecil County 142
• Charles County 134
• Dorchester County 85
• Frederick County 383
• Garrett County 79
• Harford County 317
• Howard County 234
• Kent County 47
• Montgomery County 1,332
• Prince George's County 1,450
• Queen Anne's County 45
• Somerset County 58
• St. Mary's County 43
• Talbot County 61
• Undetermined County 891
• Washington County 271
• Wicomico County 150
• Worcester County 69

Industries in Maryland

Sources are grouped by the first industry code on the facility record.

• Gasoline stations (NAICS 4471) 1,672
• Educational services (NAICS 6111) 1,375
• Real estate (NAICS 5311) 1,093
• Repair and maintenance (NAICS 8111) 850
• Religious, grantmaking and similar organizations (NAICS 8131) 385
• Personal and laundry services (NAICS 8123) 382
• Printing and related support (NAICS 3231) 262
• Nonmetallic mineral product manufacturing (NAICS 3273) 148
• Justice, public order and safety (NAICS 9221) 141
• Motor vehicle and parts dealers (NAICS 4411) 126
• Food services and drinking places (NAICS 7222) 114
• Waste management and remediation (NAICS 5622) 97
• Amusement, gambling and recreation (NAICS 7139) 97
• Food manufacturing (NAICS 3111) 89
• Petroleum and coal products manufacturing (NAICS 3241) 78
• National security and international affairs (NAICS 9281) 74
• Mining and quarrying (NAICS 2123) 74
• Hospitals (NAICS 6221) 71
• Furniture and related product manufacturing (NAICS 3371) 67
• Personal and laundry services (NAICS 8122) 62
• Educational services (NAICS 6113) 59
• Utilities (NAICS 2213) 57
• Accommodation (NAICS 7211) 53
• Nursing and residential care facilities (NAICS 6233) 53
• Warehousing and storage (NAICS 4931) 52
• Merchant wholesalers, nondurable goods (NAICS 4247) 52
• Utilities (NAICS 2211) 46
• Nursing and residential care facilities (NAICS 6231) 46
• Executive and legislative government (NAICS 9211) 46
• NAICS 4911 42
• Fabricated metal product manufacturing (NAICS 3323) 40
• Food manufacturing (NAICS 3119) 39
• Telecommunications (NAICS 5171) 38
• Food manufacturing (NAICS 3117) 35
• Rental and leasing services (NAICS 5321) 35
• Fabricated metal product manufacturing (NAICS 3328) 34
• Chemical manufacturing (NAICS 3254) 34
• Plastics and rubber products manufacturing (NAICS 3261) 34
• NAICS 4529 34
• Administration of economic programs (NAICS 9261) 34
• Professional, scientific and technical services (NAICS 5417) 34
• Food manufacturing (NAICS 3114) 33
• Administration of human resource programs (NAICS 9231) 33
• Repair and maintenance (NAICS 8114) 32
• Miscellaneous manufacturing (NAICS 3399) 31
• Other information services (NAICS 5191) 30
• Specialty trade contractors (NAICS 2389) 30
• Computer and electronic product manufacturing (NAICS 3344) 29
• Paper manufacturing (NAICS 3222) 29
• Waste management and remediation (NAICS 5629) 29
• Credit intermediation (NAICS 5221) 26
• Chemical manufacturing (NAICS 3255) 26
• Heavy and civil engineering construction (NAICS 2373) 26
• Machinery manufacturing (NAICS 3339) 25
• Beverage and tobacco manufacturing (NAICS 3121) 25
• Administration of environmental programs (NAICS 9241) 23
• NAICS 4531 22
• Food manufacturing (NAICS 3116) 20
• Food and beverage retailers (NAICS 4451) 20
• Religious, grantmaking and similar organizations (NAICS 8134) 20
• Publishing industries (NAICS 5111) 19
• Wood product manufacturing (NAICS 3211) 19
• Nonmetallic mineral product manufacturing (NAICS 3279) 19
• Plastics and rubber products manufacturing (NAICS 3262) 17
• Chemical manufacturing (NAICS 3251) 17
• Computer and electronic product manufacturing (NAICS 3345) 16
• Furniture and related product manufacturing (NAICS 3372) 16
• Merchant wholesalers, durable goods (NAICS 4239) 16
• Motion picture and sound recording (NAICS 5121) 15
• Fabricated metal product manufacturing (NAICS 3324) 15
• Building construction (NAICS 2362) 15
• Electrical equipment and appliance manufacturing (NAICS 3353) 15
• Apparel manufacturing (NAICS 3152) 15
• Wood product manufacturing (NAICS 3219) 15
• Chemical manufacturing (NAICS 3256) 15
• Food manufacturing (NAICS 3115) 15
• Religious, grantmaking and similar organizations (NAICS 8139) 14
• Repair and maintenance (NAICS 8113) 14
• Professional, scientific and technical services (NAICS 5413) 14
• Transportation equipment manufacturing (NAICS 3363) 14
• Educational services (NAICS 6116) 14
• Social assistance (NAICS 6241) 13
• Pipeline transportation (NAICS 4862) 13
• Transit and ground passenger transportation (NAICS 4851) 13
• Educational services (NAICS 6115) 13
• Specialty trade contractors (NAICS 2382) 13
• NAICS 4521 13
• Social assistance (NAICS 6242) 13
• Textile mills (NAICS 3132) 12
• Couriers and messengers (NAICS 4921) 12
• Hospitals (NAICS 6222) 12
• Support activities for transportation (NAICS 4881) 12
• Administrative and support services (NAICS 5614) 12
• Building material and garden supply stores (NAICS 4441) 12
• Chemical manufacturing (NAICS 3259) 12
• Chemical manufacturing (NAICS 3252) 11
• Utilities (NAICS 2212) 11
• Telecommunications (NAICS 5172) 11
• Chemical manufacturing (NAICS 3253) 11
• Mining and quarrying (NAICS 2121) 11
• Computer and electronic product manufacturing (NAICS 3342) 11
• Food manufacturing (NAICS 3118) 10
• Professional, scientific and technical services (NAICS 5419) 10
• Data processing and hosting (NAICS 5182) 10
• Crop production (NAICS 1114) 10
• Waste management and remediation (NAICS 5621) 10
• Machinery manufacturing (NAICS 3332) 10
• NAICS 4543 10
• Animal production (NAICS 1123) 10
• Fabricated metal product manufacturing (NAICS 3329) 10
• Miscellaneous manufacturing (NAICS 3391) 10
• Primary metal manufacturing (NAICS 3313) 9
• Telecommunications (NAICS 5174) 9
• Specialty trade contractors (NAICS 2381) 9
• Food services and drinking places (NAICS 7223) 9
• Nonmetallic mineral product manufacturing (NAICS 3271) 9
• Food services and drinking places (NAICS 7221) 9
• Merchant wholesalers, nondurable goods (NAICS 4244) 9
• Personal and laundry services (NAICS 8129) 8
• Transit and ground passenger transportation (NAICS 4853) 8
• Merchant wholesalers, durable goods (NAICS 4231) 8
• Educational services (NAICS 6112) 8
• Transit and ground passenger transportation (NAICS 4854) 8
• Support activities for transportation (NAICS 4884) 8
• Machinery manufacturing (NAICS 3335) 8
• Pipeline transportation (NAICS 4869) 7
• Transportation equipment manufacturing (NAICS 3366) 7
• Ambulatory health care services (NAICS 6211) 7
• Rental and leasing services (NAICS 5324) 7
• Primary metal manufacturing (NAICS 3312) 7
• Machinery manufacturing (NAICS 3333) 7
• Merchant wholesalers, durable goods (NAICS 4233) 6
• Merchant wholesalers, nondurable goods (NAICS 4248) 6
• Performing arts and spectator sports (NAICS 7112) 6
• Merchant wholesalers, durable goods (NAICS 4238) 6
• Primary metal manufacturing (NAICS 3315) 6
• Food services and drinking places (NAICS 7224) 6
• Truck transportation (NAICS 4842) 6
• Nonmetallic mineral product manufacturing (NAICS 3272) 6
• Rail transportation (NAICS 4821) 6
• Fabricated metal product manufacturing (NAICS 3326) 6
• Administrative and support services (NAICS 5617) 6
• Machinery manufacturing (NAICS 3334) 6
• Hospitals (NAICS 6223) 6
• Ambulatory health care services (NAICS 6215) 5
• Electrical equipment and appliance manufacturing (NAICS 3359) 5
• Primary metal manufacturing (NAICS 3314) 5
• Insurance carriers and related activities (NAICS 5242) 5
• Computer and electronic product manufacturing (NAICS 3341) 5
• NAICS 4421 5
• Support activities for transportation (NAICS 4883) 5
• Nonmetallic mineral product manufacturing (NAICS 3274) 5
• Support activities for transportation (NAICS 4889) 5
• Professional, scientific and technical services (NAICS 5418) 5
• Transit and ground passenger transportation (NAICS 4855) 5
• Insurance carriers and related activities (NAICS 5241) 5
• Museums and historical sites (NAICS 7121) 5
• Leather and allied product manufacturing (NAICS 3162) 5
• Ambulatory health care services (NAICS 6214) 5
• Textile mills (NAICS 3133) 4
• Repair and maintenance (NAICS 8112) 4
• Merchant wholesalers, nondurable goods (NAICS 4246) 4
• Motor vehicle and parts dealers (NAICS 4412) 4
• Merchant wholesalers, durable goods (NAICS 4237) 4
• Performing arts and spectator sports (NAICS 7111) 4
• Transportation equipment manufacturing (NAICS 3364) 4
• Specialty trade contractors (NAICS 2383) 4
• Broadcasting (NAICS 5151) 4
• Rental and leasing services (NAICS 5322) 4
• Machinery manufacturing (NAICS 3331) 4
• Agriculture and forestry support (NAICS 1151) 4
• Merchant wholesalers, durable goods (NAICS 4235) 3
• NAICS 4511 3
• Real estate (NAICS 5312) 3
• Ambulatory health care services (NAICS 6213) 3
• Amusement, gambling and recreation (NAICS 7131) 3
• Transit and ground passenger transportation (NAICS 4852) 3
• NAICS 5133 3
• Real estate (NAICS 5313) 3
• Mining support (NAICS 2131) 3
• Food manufacturing (NAICS 3113) 3
• Merchant wholesalers, durable goods (NAICS 4232) 3
• Religious, grantmaking and similar organizations (NAICS 8133) 3
• NAICS 4431 3
• Clothing and accessories stores (NAICS 4481) 3
• Transportation equipment manufacturing (NAICS 3362) 3

Air-emissions inspections in Maryland, by year

A compliance evaluation is the on-site or file review a state, local or federal air agency records against a permitted source.

• 2026 97
• 2025 207
• 2024 583
• 2023 594
• 2022 565
• 2021 496
• 2020 426
• 2019 465
• 2018 667
• 2017 785

High-priority air violations in Maryland, by year

A high-priority violation is the most serious class of Clean Air Act non-compliance an agency records against a source; a federally reportable violation is the next step down in severity.

• 2026 12
• 2025 10
• 2024 15
• 2023 14
• 2022 5
• 2021 13
• 2020 15
• 2019 10
• 2018 14
• 2017 11

Air-emissions stack tests in Maryland, by year

A stack test measures what a source actually emits, at the stack, against the limit in its permit.

• 2026 28
• 2025 51
• 2024 58
• 2023 49
• 2022 52
• 2021 56
• 2020 46
• 2019 54
• 2018 58
• 2017 69

Facilities

Figures from EPA’s ICIS-AIR download.