| Rank | Air Quality Index ▼ | City / Population |
| 1. | 49.9 | Fairfield, CT |
| 1. | 49.9 | Greens Farms, CT |
| 1. | 49.9 | Southport, CT / 1,711 |
| 1. | 49.9 | New Canaan, CT |
| 1. | 49.9 | Westport, CT / 27,055 |
| 1. | 49.9 | Norwalk, CT / 87,214 |
| 7. | 49.8 | Trumbull, CT / 36,444 |
| 7. | 49.8 | Bridgeport, CT / 146,680 |
| 7. | 49.8 | Darien, CT / 21,190 |
| 7. | 49.8 | Stamford, CT / 125,401 |
| 7. | 49.8 | Stratford, CT / 52,092 |
| 12. | 49.6 | Centerbrook, CT |
| 13. | 49.3 | Old Saybrook, CT |
| 13. | 49.3 | Old Saybrook Center, CT / 2,182 |
| 13. | 49.3 | Essex Village, CT / 2,174 |
| 13. | 49.3 | Old Lyme, CT |
| 13. | 49.3 | Saybrook Manor, CT / 1,045 |
| 13. | 49.3 | Westbrook Center, CT / 2,182 |
| 13. | 49.3 | Essex, CT |
| 20. | 49.2 | Madison, CT |
| 20. | 49.2 | Ivoryton, CT |
| 20. | 49.2 | Hadlyme, CT |
| 20. | 49.2 | Deep River Center, CT / 2,408 |
| 20. | 49.2 | Westbrook, CT |
| 20. | 49.2 | Chester, CT |
| 20. | 49.2 | Killingworth, CT |
| 20. | 49.2 | Chester Center, CT / 1,761 |
| 20. | 49.2 | Deep River, CT |
| 29. | 49.0 | Fenwick, CT / 65 |
| 30. | 48.1 | Easton, CT |
| 31. | 47.9 | Georgetown, CT / 1,819 |
| 31. | 47.9 | Wilton, CT |
| 31. | 47.9 | Wilton Center, CT / 676 |
| 31. | 47.9 | Cannondale, CT / 173 |
| 31. | 47.9 | Clinton, CT / 3,372 |
| 31. | 47.9 | Weston, CT |
| 31. | 47.9 | Woodmont, CT / 1,530 |
| 38. | 47.7 | South Lyme, CT |
| 38. | 47.7 | Guilford, CT |
| 38. | 47.7 | Madison Center, CT / 2,415 |
| 38. | 47.7 | Guilford Center, CT / 2,394 |
| 42. | 47.3 | Moodus, CT / 1,403 |
| 42. | 47.3 | North Branford, CT |
| 42. | 47.3 | Higganum, CT / 1,673 |
| 42. | 47.3 | Branford Center, CT / 6,255 |
| 42. | 47.3 | East Haven, CT / 29,139 |
| 42. | 47.3 | East Haddam, CT |
| 42. | 47.3 | Branford, CT |
| 42. | 47.3 | Haddam, CT |
| 50. | 46.9 | Bethlehem Village, CT / 1,783 |
| 50. | 46.9 | New Preston Marble Dale, CT |
| 50. | 46.9 | New Preston, CT / 932 |
| 50. | 46.9 | Washington Depot, CT |
| 50. | 46.9 | Morris, CT |
| 50. | 46.9 | Washington, CT |
| 50. | 46.9 | Litchfield, CT / 1,430 |
| 50. | 46.9 | Bantam, CT / 751 |
| 50. | 46.9 | Lakeside, CT |
| 50. | 46.9 | Bethlehem, CT |
| 50. | 46.9 | Plymouth, CT |
| 61. | 46.8 | Monroe, CT |
| 61. | 46.8 | Newtown, CT / 2,027 |
| 61. | 46.8 | Botsford, CT |
| 64. | 46.7 | Redding Center, CT |
| 64. | 46.7 | Redding Ridge, CT |
| 64. | 46.7 | Redding, CT |
| 64. | 46.7 | Ridgefield, CT / 7,599 |
| 68. | 46.6 | Watertown, CT / 3,549 |
| 69. | 46.5 | Durham, CT / 2,924 |
| 69. | 46.5 | Sandy Hook, CT |
| 71. | 46.5 | Quaker Hill, CT |
| 71. | 46.5 | Waterford, CT / 2,994 |
| 71. | 46.5 | Groton, CT / 9,348 |
| 71. | 46.5 | Niantic, CT / 3,032 |
| 71. | 46.5 | Roxbury, CT |
| 71. | 46.5 | East Lyme, CT |
| 71. | 46.5 | New London, CT / 27,536 |
| 71. | 46.5 | Oakdale, CT |
| 71. | 46.5 | Woodbury, CT |
| 80. | 46.4 | Woodbury Center, CT / 1,421 |
| 80. | 46.4 | New Milford, CT / 6,568 |
| 82. | 45.9 | Milford, CT / 51,509 |
| 82. | 45.9 | Staffordville, CT |
| 82. | 45.9 | Shelton, CT / 40,472 |
| 82. | 45.9 | Stafford, CT |
| 86. | 45.8 | New Haven, CT / 130,553 |
| 86. | 45.8 | West Haven, CT / 55,290 |
| 86. | 45.8 | Orange, CT / 13,947 |
| 89. | 45.7 | Salem, CT |
| 89. | 45.7 | Gilman, CT |
| 89. | 45.7 | Bozrah, CT |
| 92. | 45.5 | Stafford Springs, CT / 4,734 |
| 92. | 45.5 | Somersville, CT |
| 92. | 45.5 | Harwinton, CT |
| 92. | 45.5 | Thomaston, CT / 1,727 |
| 92. | 45.5 | Hazardville, CT / 4,863 |
| 92. | 45.5 | Pequabuck, CT |
| 92. | 45.5 | Oakville, CT / 9,118 |
| 92. | 45.5 | Torrington, CT / 35,774 |
| 92. | 45.5 | Terryville, CT / 5,121 |
| 92. | 45.5 | Northwest Harwinton, CT / 3,186 |
| 92. | 45.5 | Northfield, CT |
| 92. | 45.5 | Somers, CT / 1,733 |
| 104. | 45.4 | Greenwich, CT / 13,221 |
| 104. | 45.4 | Glenville, CT / 2,383 |
| 104. | 45.4 | Cos Cob, CT / 6,265 |
| 104. | 45.4 | Pemberwick, CT / 4,058 |
| 104. | 45.4 | Riverside, CT / 8,682 |
| 104. | 45.4 | Old Greenwich, CT / 6,520 |
| 104. | 45.4 | Eastford, CT |
| 104. | 45.4 | Byram, CT / 4,885 |
| 112. | 45.3 | Wolcott, CT |
| 112. | 45.3 | Marion, CT |
| 114. | 45.2 | Pine Meadow, CT |
| 114. | 45.2 | Pomfret, CT |
| 114. | 45.2 | New Hartford Center, CT / 1,509 |
| 114. | 45.2 | Rockfall, CT |
| 114. | 45.2 | New Hartford, CT |
| 119. | 45.1 | Hamden, CT |
| 119. | 45.1 | Woodbridge, CT |
| 119. | 45.1 | Colebrook, CT |
| 119. | 45.1 | Woodstock Valley, CT |
| 119. | 45.1 | Derby, CT / 12,837 |
| 119. | 45.1 | Winchester Center, CT |
| 119. | 45.1 | Colchester, CT / 4,414 |
| 119. | 45.1 | Lebanon, CT |
| 119. | 45.1 | Seymour, CT |
| 119. | 45.1 | Northford, CT |
| 119. | 45.1 | Ansonia, CT / 19,128 |
| 130. | 45.0 | Wallingford, CT |
| 130. | 45.0 | North Haven, CT / 23,997 |
| 130. | 45.0 | Milldale, CT |
| 130. | 45.0 | Willington, CT |
| 130. | 45.0 | Crystal Lake, CT / 2,378 |
| 130. | 45.0 | South Windham, CT / 1,603 |
| 130. | 45.0 | Meriden, CT / 60,616 |
| 130. | 45.0 | Wallingford Center, CT / 17,824 |
| 130. | 45.0 | Plantsville, CT |
| 139. | 44.9 | North Franklin, CT |
| 139. | 44.9 | Chaplin, CT |
| 139. | 44.9 | New Fairfield, CT |
| 139. | 44.9 | North Windham, CT |
| 139. | 44.9 | Woodstock, CT |
| 139. | 44.9 | Preston, CT |
| 139. | 44.9 | Southbury, CT |
| 139. | 44.9 | North Stonington, CT |
| 139. | 44.9 | Pomfret Center, CT |
| 139. | 44.9 | Southington, CT |
| 139. | 44.9 | Ledyard, CT |
| 139. | 44.9 | West Mystic, CT |
| 139. | 44.9 | Montville, CT |
| 139. | 44.9 | Stevenson, CT |
| 139. | 44.9 | Taftville, CT |
| 139. | 44.9 | Hawleyville, CT |
| 139. | 44.9 | South Britain, CT |
| 139. | 44.9 | Hanover, CT |
| 139. | 44.9 | Uncasville, CT |
| 139. | 44.9 | Middlefield, CT |
| 139. | 44.9 | Versailles, CT |
| 139. | 44.9 | Voluntown, CT |
| 139. | 44.9 | Plainfield, CT |
| 139. | 44.9 | Canterbury, CT |
| 139. | 44.9 | Baltic, CT / 1,142 |
| 139. | 44.9 | Norwich, CT / 40,378 |
| 139. | 44.9 | Stonington, CT / 1,066 |
| 139. | 44.9 | Noank, CT / 2,100 |
| 139. | 44.9 | Mystic, CT / 3,905 |
| 139. | 44.9 | Mashantucket, CT / 299 |
| 139. | 44.9 | Abington, CT |
| 139. | 44.9 | Long Hill, CT / 4,148 |
| 139. | 44.9 | Berlin, CT |
| 139. | 44.9 | Gales Ferry, CT / 885 |
| 139. | 44.9 | Groton Long Point, CT / 445 |
| 139. | 44.9 | Heritage Village, CT / 4,126 |
| 139. | 44.9 | Jewett City, CT / 3,488 |
| 139. | 44.9 | Poquonock Bridge, CT / 1,649 |
| 139. | 44.9 | Old Mystic, CT / 3,559 |
| 139. | 44.9 | Conning Towers Nautilus Park, CT / 10,130 |
| 139. | 44.9 | Oxoboxo River, CT / 3,230 |
| 139. | 44.9 | South Woodstock, CT / 1,150 |
| 139. | 44.9 | Pawcatuck, CT / 5,428 |
| 139. | 44.9 | Yantic, CT |
| 139. | 44.9 | Plainfield Village, CT / 2,117 |
| 139. | 44.9 | Bridgewater, CT |
| 139. | 44.9 | Brookfield, CT |
| 186. | 44.8 | Scotland, CT |
| 186. | 44.8 | Windham, CT |
| 186. | 44.8 | Brooklyn, CT / 889 |
| 186. | 44.8 | Hampton, CT |
| 190. | 44.7 | Lakeville, CT / 761 |
| 190. | 44.7 | Sherwood Manor, CT / 5,449 |
| 190. | 44.7 | Thompsonville, CT / 9,021 |
| 190. | 44.7 | Sharon, CT / 662 |
| 190. | 44.7 | Goshen, CT |
| 190. | 44.7 | South Willington, CT |
| 190. | 44.7 | Tolland, CT |
| 190. | 44.7 | Falls Village, CT / 481 |
| 190. | 44.7 | Cornwall Bridge, CT |
| 190. | 44.7 | Cornwall, CT |
| 190. | 44.7 | West Cornwall, CT |
| 190. | 44.7 | Bethel, CT / 9,471 |
| 190. | 44.7 | Danbury, CT / 82,781 |
| 190. | 44.7 | Moosup, CT / 3,032 |
| 204. | 44.6 | Mansfield Depot, CT |
| 204. | 44.6 | East Brooklyn, CT / 1,784 |
| 204. | 44.6 | Coventry Lake, CT / 3,417 |
| 204. | 44.6 | Oxford, CT |
| 204. | 44.6 | Middlebury, CT |
| 204. | 44.6 | Coventry, CT |
| 204. | 44.6 | Storrs, CT / 15,374 |
| 204. | 44.6 | South Coventry, CT / 1,036 |
| 204. | 44.6 | Canaan, CT / 1,178 |
| 204. | 44.6 | Broad Brook, CT / 4,526 |
| 204. | 44.6 | Rockville, CT / 7,348 |
| 204. | 44.6 | East Canaan, CT |
| 204. | 44.6 | Naugatuck, CT / 31,790 |
| 204. | 44.6 | Rogers, CT |
| 204. | 44.6 | Beacon Falls, CT |
| 204. | 44.6 | Ellington, CT |
| 204. | 44.6 | Mansfield Center, CT / 1,055 |
| 204. | 44.6 | Sherman, CT |
| 204. | 44.6 | Willimantic, CT / 17,845 |
| 204. | 44.6 | Bethany, CT |
| 204. | 44.6 | Ashford, CT |
| 204. | 44.6 | Storrs Mansfield, CT |
| 226. | 44.5 | Kensington, CT / 9,492 |
| 226. | 44.5 | North Westchester, CT |
| 226. | 44.5 | Lake Pocotopaug, CT / 2,994 |
| 226. | 44.5 | Portland, CT / 5,634 |
| 226. | 44.5 | Cheshire Village, CT / 5,264 |
| 226. | 44.5 | East Hampton, CT / 2,402 |
| 226. | 44.5 | Rocky Hill, CT |
| 226. | 44.5 | Middletown, CT / 47,424 |
| 226. | 44.5 | Marlborough, CT |
| 226. | 44.5 | Prospect, CT |
| 226. | 44.5 | Norfolk, CT / 666 |
| 226. | 44.5 | South Glastonbury, CT |
| 226. | 44.5 | Amston, CT |
| 226. | 44.5 | Cobalt, CT |
| 226. | 44.5 | Cheshire, CT |
| 226. | 44.5 | Cromwell, CT |
| 226. | 44.5 | Waterbury, CT / 109,887 |
| 226. | 44.5 | Terramuggus, CT / 837 |
| 226. | 44.5 | Middle Haddam, CT |
| 226. | 44.5 | East Berlin, CT |
| 246. | 44.5 | Burlington, CT |
| 246. | 44.5 | Winsted, CT / 7,876 |
| 248. | 44.4 | Bristol, CT / 60,556 |
| 248. | 44.4 | Plainville, CT |
| 250. | 44.3 | Quinebaug, CT / 974 |
| 250. | 44.3 | Fabyan, CT |
| 250. | 44.3 | Kent, CT |
| 250. | 44.3 | Salisbury, CT |
| 250. | 44.3 | Grosvenor Dale, CT |
| 250. | 44.3 | Gaylordsville, CT |
| 250. | 44.3 | North Grosvenordale, CT |
| 250. | 44.3 | Taconic, CT |
| 250. | 44.3 | East Woodstock, CT |
| 250. | 44.3 | Oneco, CT |
| 250. | 44.3 | North Grosvenor Dale, CT / 1,614 |
| 250. | 44.3 | South Kent, CT |
| 262. | 44.1 | East Windsor, CT |
| 262. | 44.1 | Andover, CT |
| 262. | 44.1 | South Windsor, CT |
| 262. | 44.1 | East Windsor Hill, CT |
| 262. | 44.1 | Vernon Rockville, CT |
| 262. | 44.1 | West Hartland, CT |
| 262. | 44.1 | Manchester, CT / 30,621 |
| 262. | 44.1 | Bolton, CT |
| 262. | 44.1 | Riverton, CT |
| 262. | 44.1 | Collinsville, CT / 3,851 |
| 272. | 44.0 | New Britain, CT / 73,095 |
| 272. | 44.0 | Newington, CT / 30,652 |
| 272. | 44.0 | Glastonbury Center, CT / 7,418 |
| 272. | 44.0 | Hartford, CT / 125,211 |
| 272. | 44.0 | East Hartford, CT / 51,211 |
| 272. | 44.0 | Unionville, CT |
| 272. | 44.0 | Putnam, CT / 7,249 |
| 272. | 44.0 | West Hartford, CT / 63,396 |
| 272. | 44.0 | East Glastonbury, CT |
| 272. | 44.0 | Wethersfield, CT / 26,579 |
| 272. | 44.0 | Columbia, CT |
| 272. | 44.0 | Avon, CT |
| 272. | 44.0 | Farmington, CT |
| 272. | 44.0 | Glastonbury, CT |
| 272. | 44.0 | Hebron, CT |
| 287. | 43.8 | Suffield, CT |
| 287. | 43.8 | Southwood Acres, CT / 8,060 |
| 287. | 43.8 | Suffield Depot, CT / 1,372 |
| 287. | 43.8 | Enfield, CT |
| 291. | 43.7 | North Granby, CT / 1,786 |
| 291. | 43.7 | Granby, CT |
| 291. | 43.7 | East Hartland, CT |
| 291. | 43.7 | Salmon Brook, CT / 2,766 |
| 291. | 43.7 | West Suffield, CT |
| 296. | 43.6 | Canton Center, CT |
| 296. | 43.6 | Canton, CT |
| 296. | 43.6 | Central Village, CT |
| 296. | 43.6 | Canton Valley, CT / 1,484 |
| 300. | 43.5 | Wauregan, CT / 1,210 |
| 300. | 43.5 | Barkhamsted, CT |
| 302. | 43.3 | Sterling, CT |
| 303. | 43.2 | Thompson, CT |
| 303. | 43.2 | North Canton, CT |
| 305. | 43.1 | West Simsbury, CT / 2,446 |
| 305. | 43.1 | Windsor, CT |
| 305. | 43.1 | Poquonock, CT |
| 305. | 43.1 | Simsbury Center, CT / 5,843 |
| 305. | 43.1 | Tariffville, CT / 1,371 |
| 305. | 43.1 | Danielson, CT / 4,023 |
| 305. | 43.1 | East Killingly, CT |
| 305. | 43.1 | Simsbury, CT |
| 305. | 43.1 | Ballouville, CT |
| 305. | 43.1 | Bloomfield, CT |
| 305. | 43.1 | Dayville, CT |
| 316. | 43.0 | Weatogue, CT / 3,012 |
| 316. | 43.0 | Blue Hills, CT / 2,735 |
| 318. | 42.9 | East Granby, CT |
| 318. | 42.9 | Windsor Locks, CT / 12,554 |
| 320. | 42.8 | West Granby, CT |
Please note that we only rank locations with 'Air Quality Index' data. The rank above might not be a complete list. Locations without 'Air Quality Index' data are not listed.
