Home › Air Quality › Is air quality getting better or worse?
Is U.S. Air Quality Getting Better or Worse?
EPA monitor data through 2025 · Updated August 13, 2026 · Methods
Better — substantially. But the official scorecard understates it, because
EPA changed what an Air Quality Index of 100 means. Twice. Take the 35 metropolitan areas EPA charted in
its own 2011 trends report: in 2010 they recorded 632 days above AQI 100
as EPA printed it. Score the identical air from the same monitors under today's rules and
you get about 1160 — 1.7 times as many.
Neither number is wrong. They are answers to different questions, and no published chart says so.
2010 unhealthy days, 2010 rules
684
35 metros, EPA's own selection
Same air, today's rules
1160
1.7× the count
As EPA printed it in 2011
632
Figure 6, Our Nation's Air
What changed
The AQI is a 0–500 scale, and 100 is the line between “moderate” and
“unhealthy for sensitive groups.” That line is pinned to the national health standard for each
pollutant, so when the standard moves, the line moves:
Fine particles (PM2.5), effective 2013. The concentration scoring 100 fell from
40.4 to 35.4 micrograms per cubic metre.Ozone, effective 2015. The concentration scoring 100 fell from 75 to 70 parts
per billion.
A day at 72 ppb of ozone was “moderate” in 2014 and is “unhealthy for sensitive
groups” now. The air did not change. The label did.
The 35 metros, scored both ways
Days above AQI 100 across 35 metros, scored by the 2010 rulebook
0
600
1,200
1,800
2,400
2000
2005
2010
2015
2020
2025
2000: 1,622 days 2001: 1,611 days 2002: 1,615 days 2003: 1,216 days 2004: 944 days 2005: 1,431 days 2006: 1,406 days 2007: 1,448 days 2008: 930 days 2009: 543 days 2010: 684 days 2011: 841 days 2012: 835 days 2013: 435 days 2014: 388 days 2015: 397 days 2016: 404 days 2017: 430 days 2018: 452 days 2019: 253 days 2020: 571 days 2021: 547 days 2022: 367 days 2023: 506 days 2024: 475 days 2025: 321 days
Days above AQI 100 across all 35 metros, scored by the rulebook in force when
EPA published its 2011 report.
Days above AQI 100 across 35 metros, scored by today's rulebook
0
600
1,200
1,800
2,400
2000
2005
2010
2015
2020
2025
2000: 2,292 days 2001: 2,282 days 2002: 2,156 days 2003: 1,821 days 2004: 1,475 days 2005: 2,056 days 2006: 1,986 days 2007: 2,031 days 2008: 1,407 days 2009: 853 days 2010: 1,160 days 2011: 1,335 days 2012: 1,335 days 2013: 738 days 2014: 685 days 2015: 741 days 2016: 749 days 2017: 755 days 2018: 806 days 2019: 506 days 2020: 794 days 2021: 834 days 2022: 650 days 2023: 846 days 2024: 799 days 2025: 540 days
The same monitor data, same metros, scored by today's rulebook. Both panels use
one fixed definition for every year, so each is internally consistent.
What the redefinition does and does not distort
The level is badly distorted. Any single year scores roughly 1.4 to 2 times worse
under today's rules. Setting a figure published before 2013 beside one published after 2015,
which is what “extending the chart” would mean, compares two different measurements.The trend is only mildly distorted. Across these metros, unhealthy days fell
80% from 2000 to 2025 under the 2010 rules and
76% under today's. Both show a large improvement. The newer
definition understates it, but not dramatically.It is mostly the ozone change, not particles. Of the
53,195 area-days that flipped from satisfactory to unhealthy purely
because of the redefinition, 81% were ozone and only
19% were fine particles. The particle change is the one usually blamed;
it is the smaller one.
The 2013 particle change fixed an inconsistency rather than creating one. EPA
tightened the 24-hour PM2.5 health standard to 35 µg/m³ in December 2006 but left the
AQI's unhealthy line at 40.4 until March 2013. In between, 2,338
metro-days sat above the concentration defining EPA's own health standard while being reported
to the public as “moderate.” The 2013 revision closed a seven-year gap.
Every metro, both scorings
Sorted by unhealthy days in 2025 under current rules. Faded columns mark years with fewer than
300 monitored days, where the count is not comparable.
Los Angeles
Los Angeles-Long Beach-Anaheim, CA · 2025: 71 unhealthy days by the 2010
rules, 99 by today's. EPA printed 74 for 2010.
Los Angeles: unhealthy days by the 2010 rules
0
50
100
150
200
2000
2005
2010
2015
2020
2025
2000: 152 days 2001: 156 days 2002: 155 days 2003: 148 days 2004: 137 days 2005: 115 days 2006: 110 days 2007: 105 days 2008: 99 days 2009: 104 days 2010: 81 days 2011: 97 days 2012: 94 days 2013: 71 days 2014: 82 days 2015: 95 days 2016: 69 days 2017: 89 days 2018: 64 days 2019: 62 days 2020: 114 days 2021: 73 days 2022: 65 days 2023: 67 days 2024: 106 days 2025: 71 days
Los Angeles: unhealthy days by today's rules
0
50
100
150
200
2000
2005
2010
2015
2020
2025
2000: 178 days 2001: 187 days 2002: 182 days 2003: 173 days 2004: 161 days 2005: 139 days 2006: 131 days 2007: 128 days 2008: 129 days 2009: 123 days 2010: 115 days 2011: 121 days 2012: 132 days 2013: 103 days 2014: 108 days 2015: 134 days 2016: 108 days 2017: 121 days 2018: 110 days 2019: 91 days 2020: 142 days 2021: 98 days 2022: 94 days 2023: 87 days 2024: 134 days 2025: 99 days
Phoenix
Phoenix-Mesa-Scottsdale, AZ · 2025: 39 unhealthy days by the 2010
rules, 56 by today's. EPA printed 11 for 2010.
Phoenix: unhealthy days by the 2010 rules
0
70
140
210
280
2000
2005
2010
2015
2020
2025
2000: 137 days 2001: 54 days 2002: 52 days 2003: 52 days 2004: 27 days 2005: 66 days 2006: 255 days 2007: 205 days 2008: 191 days 2009: 67 days 2010: 44 days 2011: 121 days 2012: 92 days 2013: 87 days 2014: 106 days 2015: 45 days 2016: 53 days 2017: 72 days 2018: 59 days 2019: 33 days 2020: 209 days 2021: 204 days 2022: 81 days 2023: 62 days 2024: 84 days 2025: 39 days
Phoenix: unhealthy days by today's rules
0
70
140
210
280
2000
2005
2010
2015
2020
2025
2000: 167 days 2001: 88 days 2002: 90 days 2003: 84 days 2004: 55 days 2005: 90 days 2006: 267 days 2007: 222 days 2008: 201 days 2009: 77 days 2010: 59 days 2011: 133 days 2012: 111 days 2013: 105 days 2014: 119 days 2015: 70 days 2016: 75 days 2017: 95 days 2018: 85 days 2019: 54 days 2020: 230 days 2021: 238 days 2022: 108 days 2023: 85 days 2024: 114 days 2025: 56 days
Houston
Houston-The Woodlands-Sugar Land, TX · 2025: 33 unhealthy days by the 2010
rules, 46 by today's. EPA printed 33 for 2010.
Houston: unhealthy days by the 2010 rules
0
20
40
60
80
100
2000
2005
2010
2015
2020
2025
2000: 74 days 2001: 68 days 2002: 56 days 2003: 65 days 2004: 62 days 2005: 81 days 2006: 60 days 2007: 44 days 2008: 31 days 2009: 29 days 2010: 34 days 2011: 38 days 2012: 33 days 2013: 18 days 2014: 7 days 2015: 30 days 2016: 12 days 2017: 20 days 2018: 18 days 2019: 24 days 2020: 14 days 2021: 19 days 2022: 20 days 2023: 46 days 2024: 38 days 2025: 33 days
Houston: unhealthy days by today's rules
0
20
40
60
80
100
2000
2005
2010
2015
2020
2025
2000: 88 days 2001: 84 days 2002: 67 days 2003: 78 days 2004: 74 days 2005: 100 days 2006: 78 days 2007: 54 days 2008: 46 days 2009: 32 days 2010: 43 days 2011: 57 days 2012: 48 days 2013: 24 days 2014: 14 days 2015: 45 days 2016: 23 days 2017: 25 days 2018: 35 days 2019: 31 days 2020: 24 days 2021: 30 days 2022: 39 days 2023: 57 days 2024: 63 days 2025: 46 days
Dallas
Dallas-Fort Worth-Arlington, TX · 2025: 29 unhealthy days by the 2010
rules, 45 by today's. EPA printed 15 for 2010.
Dallas: unhealthy days by the 2010 rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 63 days 2001: 51 days 2002: 54 days 2003: 48 days 2004: 48 days 2005: 70 days 2006: 50 days 2007: 27 days 2008: 32 days 2009: 34 days 2010: 18 days 2011: 40 days 2012: 37 days 2013: 33 days 2014: 12 days 2015: 29 days 2016: 8 days 2017: 10 days 2018: 25 days 2019: 13 days 2020: 10 days 2021: 18 days 2022: 27 days 2023: 34 days 2024: 36 days 2025: 29 days
Dallas: unhealthy days by today's rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 75 days 2001: 77 days 2002: 65 days 2003: 68 days 2004: 61 days 2005: 85 days 2006: 67 days 2007: 45 days 2008: 48 days 2009: 51 days 2010: 28 days 2011: 66 days 2012: 62 days 2013: 46 days 2014: 27 days 2015: 44 days 2016: 18 days 2017: 24 days 2018: 36 days 2019: 29 days 2020: 24 days 2021: 31 days 2022: 52 days 2023: 53 days 2024: 54 days 2025: 45 days
Chicago
Chicago-Naperville-Elgin, IL-IN-WI · 2025: 24 unhealthy days by the 2010
rules, 32 by today's. EPA printed 28 for 2010.
Chicago: unhealthy days by the 2010 rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 37 days 2001: 68 days 2002: 47 days 2003: 38 days 2004: 27 days 2005: 46 days 2006: 18 days 2007: 40 days 2008: 31 days 2009: 12 days 2010: 22 days 2011: 16 days 2012: 31 days 2013: 9 days 2014: 10 days 2015: 8 days 2016: 16 days 2017: 12 days 2018: 18 days 2019: 3 days 2020: 15 days 2021: 13 days 2022: 7 days 2023: 26 days 2024: 8 days 2025: 24 days
Chicago: unhealthy days by today's rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 62 days 2001: 89 days 2002: 66 days 2003: 58 days 2004: 41 days 2005: 74 days 2006: 24 days 2007: 58 days 2008: 45 days 2009: 22 days 2010: 35 days 2011: 24 days 2012: 50 days 2013: 17 days 2014: 18 days 2015: 14 days 2016: 28 days 2017: 25 days 2018: 26 days 2019: 13 days 2020: 24 days 2021: 28 days 2022: 15 days 2023: 43 days 2024: 17 days 2025: 32 days
San Diego
San Diego-Carlsbad, CA · 2025: 14 unhealthy days by the 2010
rules, 32 by today's. EPA printed 14 for 2010.
San Diego: unhealthy days by the 2010 rules
0
20
40
60
80
100
2000
2005
2010
2015
2020
2025
2000: 68 days 2001: 60 days 2002: 43 days 2003: 58 days 2004: 33 days 2005: 31 days 2006: 42 days 2007: 37 days 2008: 45 days 2009: 28 days 2010: 18 days 2011: 13 days 2012: 19 days 2013: 17 days 2014: 15 days 2015: 16 days 2016: 16 days 2017: 29 days 2018: 12 days 2019: 8 days 2020: 32 days 2021: 7 days 2022: 11 days 2023: 17 days 2024: 21 days 2025: 14 days
San Diego: unhealthy days by today's rules
0
20
40
60
80
100
2000
2005
2010
2015
2020
2025
2000: 98 days 2001: 89 days 2002: 76 days 2003: 79 days 2004: 56 days 2005: 55 days 2006: 71 days 2007: 61 days 2008: 75 days 2009: 49 days 2010: 25 days 2011: 34 days 2012: 36 days 2013: 37 days 2014: 39 days 2015: 41 days 2016: 41 days 2017: 60 days 2018: 35 days 2019: 25 days 2020: 49 days 2021: 16 days 2022: 26 days 2023: 43 days 2024: 51 days 2025: 32 days
Las Vegas
Las Vegas-Henderson-Paradise, NV · 2025: 13 unhealthy days by the 2010
rules, 25 by today's. EPA printed 2 for 2010.
Las Vegas: unhealthy days by the 2010 rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 31 days 2001: 35 days 2002: 42 days 2003: 44 days 2004: 23 days 2005: 35 days 2006: 35 days 2007: 25 days 2008: 12 days 2009: 7 days 2010: 7 days 2011: 20 days 2012: 29 days 2013: 14 days 2014: 7 days 2015: 7 days 2016: 9 days 2017: 13 days 2018: 25 days 2019: 1 days 2020: 12 days 2021: 9 days 2022: 15 days 2023: 7 days 2024: 17 days 2025: 13 days
Las Vegas: unhealthy days by today's rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 55 days 2001: 76 days 2002: 68 days 2003: 68 days 2004: 47 days 2005: 63 days 2006: 63 days 2007: 48 days 2008: 32 days 2009: 22 days 2010: 31 days 2011: 44 days 2012: 53 days 2013: 38 days 2014: 16 days 2015: 23 days 2016: 25 days 2017: 29 days 2018: 49 days 2019: 5 days 2020: 25 days 2021: 34 days 2022: 26 days 2023: 25 days 2024: 38 days 2025: 25 days
New York
New York-Newark-Jersey City, NY-NJ-PA · 2025: 12 unhealthy days by the 2010
rules, 25 by today's. EPA printed 37 for 2010.
New York: unhealthy days by the 2010 rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 44 days 2001: 69 days 2002: 69 days 2003: 41 days 2004: 37 days 2005: 53 days 2006: 49 days 2007: 49 days 2008: 37 days 2009: 20 days 2010: 38 days 2011: 26 days 2012: 23 days 2013: 11 days 2014: 8 days 2015: 22 days 2016: 13 days 2017: 12 days 2018: 13 days 2019: 9 days 2020: 4 days 2021: 14 days 2022: 4 days 2023: 17 days 2024: 16 days 2025: 12 days
New York: unhealthy days by today's rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 65 days 2001: 89 days 2002: 86 days 2003: 61 days 2004: 51 days 2005: 71 days 2006: 65 days 2007: 66 days 2008: 52 days 2009: 35 days 2010: 61 days 2011: 33 days 2012: 39 days 2013: 21 days 2014: 16 days 2015: 38 days 2016: 29 days 2017: 19 days 2018: 27 days 2019: 16 days 2020: 11 days 2021: 21 days 2022: 11 days 2023: 24 days 2024: 24 days 2025: 25 days
Denver
Denver-Aurora-Lakewood, CO · 2025: 3 unhealthy days by the 2010
rules, 17 by today's. EPA printed 8 for 2010.
Denver: unhealthy days by the 2010 rules
0
20
40
60
80
100
2000
2005
2010
2015
2020
2025
2000: 27 days 2001: 26 days 2002: 30 days 2003: 44 days 2004: 11 days 2005: 18 days 2006: 33 days 2007: 59 days 2008: 32 days 2009: 8 days 2010: 18 days 2011: 18 days 2012: 32 days 2013: 24 days 2014: 12 days 2015: 15 days 2016: 16 days 2017: 10 days 2018: 34 days 2019: 7 days 2020: 24 days 2021: 45 days 2022: 17 days 2023: 14 days 2024: 22 days 2025: 3 days
Denver: unhealthy days by today's rules
0
20
40
60
80
100
2000
2005
2010
2015
2020
2025
2000: 51 days 2001: 40 days 2002: 45 days 2003: 62 days 2004: 26 days 2005: 41 days 2006: 60 days 2007: 90 days 2008: 53 days 2009: 15 days 2010: 38 days 2011: 54 days 2012: 68 days 2013: 44 days 2014: 34 days 2015: 26 days 2016: 28 days 2017: 39 days 2018: 56 days 2019: 24 days 2020: 35 days 2021: 69 days 2022: 36 days 2023: 29 days 2024: 41 days 2025: 17 days
Salt Lake City
Salt Lake City, UT · 2025: 5 unhealthy days by the 2010
rules, 17 by today's. EPA printed 17 for 2010.
Salt Lake City: unhealthy days by the 2010 rules
0
20
40
60
2000
2005
2010
2015
2020
2025
2000: 33 days 2001: 39 days 2002: 46 days 2003: 23 days 2004: 40 days 2005: 42 days 2006: 32 days 2007: 37 days 2008: 17 days 2009: 20 days 2010: 18 days 2011: 15 days 2012: 10 days 2013: 40 days 2014: 14 days 2015: 17 days 2016: 16 days 2017: 22 days 2018: 20 days 2019: 6 days 2020: 11 days 2021: 30 days 2022: 13 days 2023: 9 days 2024: 25 days 2025: 5 days
Salt Lake City: unhealthy days by today's rules
0
20
40
60
2000
2005
2010
2015
2020
2025
2000: 52 days 2001: 54 days 2002: 66 days 2003: 39 days 2004: 55 days 2005: 60 days 2006: 54 days 2007: 63 days 2008: 33 days 2009: 37 days 2010: 24 days 2011: 30 days 2012: 17 days 2013: 50 days 2014: 22 days 2015: 27 days 2016: 28 days 2017: 48 days 2018: 43 days 2019: 18 days 2020: 24 days 2021: 49 days 2022: 27 days 2023: 16 days 2024: 41 days 2025: 17 days
Detroit
Detroit-Warren-Dearborn, MI · 2025: 10 unhealthy days by the 2010
rules, 16 by today's. EPA printed 23 for 2010.
Detroit: unhealthy days by the 2010 rules
0
10
20
30
40
50
60
2000
2005
2010
2015
2020
2025
2000: 21 days 2001: 44 days 2002: 37 days 2003: 30 days 2004: 16 days 2005: 37 days 2006: 14 days 2007: 22 days 2008: 7 days 2009: 4 days 2010: 13 days 2011: 13 days 2012: 23 days 2013: 4 days 2014: 6 days 2015: 6 days 2016: 12 days 2017: 7 days 2018: 7 days 2019: 5 days 2020: 9 days 2021: 4 days 2022: 8 days 2023: 12 days 2024: 4 days 2025: 10 days
Detroit: unhealthy days by today's rules
0
10
20
30
40
50
60
2000
2005
2010
2015
2020
2025
2000: 32 days 2001: 58 days 2002: 48 days 2003: 39 days 2004: 27 days 2005: 48 days 2006: 25 days 2007: 33 days 2008: 15 days 2009: 13 days 2010: 22 days 2011: 21 days 2012: 35 days 2013: 10 days 2014: 13 days 2015: 16 days 2016: 18 days 2017: 12 days 2018: 14 days 2019: 12 days 2020: 19 days 2021: 9 days 2022: 16 days 2023: 25 days 2024: 11 days 2025: 16 days
Cincinnati
Cincinnati, OH-KY-IN · 2025: 8 unhealthy days by the 2010
rules, 15 by today's. EPA printed 18 for 2010.
Cincinnati: unhealthy days by the 2010 rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 31 days 2001: 39 days 2002: 49 days 2003: 28 days 2004: 19 days 2005: 49 days 2006: 25 days 2007: 49 days 2008: 17 days 2009: 8 days 2010: 25 days 2011: 25 days 2012: 30 days 2013: 3 days 2014: 2 days 2015: 4 days 2016: 8 days 2017: 4 days 2018: 7 days 2019: 3 days 2020: 4 days 2021: 4 days 2022: 2 days 2023: 13 days 2024: 5 days 2025: 8 days
Cincinnati: unhealthy days by today's rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 44 days 2001: 58 days 2002: 60 days 2003: 41 days 2004: 32 days 2005: 64 days 2006: 41 days 2007: 72 days 2008: 36 days 2009: 15 days 2010: 45 days 2011: 37 days 2012: 46 days 2013: 9 days 2014: 13 days 2015: 11 days 2016: 18 days 2017: 9 days 2018: 13 days 2019: 9 days 2020: 7 days 2021: 8 days 2022: 6 days 2023: 23 days 2024: 14 days 2025: 15 days
St. Louis
St. Louis, MO-IL · 2025: 11 unhealthy days by the 2010
rules, 15 by today's. EPA printed 21 for 2010.
St. Louis: unhealthy days by the 2010 rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 36 days 2001: 48 days 2002: 67 days 2003: 37 days 2004: 28 days 2005: 64 days 2006: 54 days 2007: 44 days 2008: 11 days 2009: 8 days 2010: 26 days 2011: 31 days 2012: 51 days 2013: 10 days 2014: 7 days 2015: 5 days 2016: 13 days 2017: 4 days 2018: 11 days 2019: 5 days 2020: 5 days 2021: 9 days 2022: 10 days 2023: 17 days 2024: 12 days 2025: 11 days
St. Louis: unhealthy days by today's rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 52 days 2001: 75 days 2002: 80 days 2003: 58 days 2004: 41 days 2005: 81 days 2006: 76 days 2007: 56 days 2008: 24 days 2009: 17 days 2010: 46 days 2011: 47 days 2012: 70 days 2013: 20 days 2014: 21 days 2015: 14 days 2016: 19 days 2017: 12 days 2018: 19 days 2019: 9 days 2020: 11 days 2021: 15 days 2022: 15 days 2023: 24 days 2024: 16 days 2025: 15 days
Philadelphia
Philadelphia-Camden-Wilmington, PA-NJ-DE-MD · 2025: 6 unhealthy days by the 2010
rules, 13 by today's. EPA printed 32 for 2010.
Philadelphia: unhealthy days by the 2010 rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 40 days 2001: 62 days 2002: 63 days 2003: 38 days 2004: 27 days 2005: 44 days 2006: 40 days 2007: 45 days 2008: 33 days 2009: 11 days 2010: 34 days 2011: 18 days 2012: 24 days 2013: 8 days 2014: 9 days 2015: 16 days 2016: 12 days 2017: 13 days 2018: 11 days 2019: 6 days 2020: 3 days 2021: 6 days 2022: 2 days 2023: 9 days 2024: 8 days 2025: 6 days
Philadelphia: unhealthy days by today's rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 62 days 2001: 80 days 2002: 83 days 2003: 62 days 2004: 50 days 2005: 62 days 2006: 59 days 2007: 58 days 2008: 49 days 2009: 24 days 2010: 48 days 2011: 31 days 2012: 43 days 2013: 19 days 2014: 20 days 2015: 30 days 2016: 18 days 2017: 21 days 2018: 19 days 2019: 15 days 2020: 8 days 2021: 15 days 2022: 6 days 2023: 25 days 2024: 15 days 2025: 13 days
Minneapolis
Minneapolis-St. Paul-Bloomington, MN-WI · 2025: 9 unhealthy days by the 2010
rules, 11 by today's. EPA printed 3 for 2010.
Minneapolis: unhealthy days by the 2010 rules
0
8
16
24
32
2000
2005
2010
2015
2020
2025
2000: 11 days 2001: 14 days 2002: 7 days 2003: 13 days 2004: 4 days 2005: 14 days 2006: 6 days 2007: 10 days 2008: 2 days 2009: 5 days 2010: 4 days 2011: 1 days 2012: 3 days 2013: 1 days 2014: 1 days 2015: 3 days 2016: 2 days 2017: 1 days 2018: 2 days 2019: 1 days 2020: 2 days 2021: 5 days 2022: 0 days 2023: 17 days 2024: 3 days 2025: 9 days
Minneapolis: unhealthy days by today's rules
0
8
16
24
32
2000
2005
2010
2015
2020
2025
2000: 24 days 2001: 28 days 2002: 17 days 2003: 23 days 2004: 9 days 2005: 23 days 2006: 10 days 2007: 13 days 2008: 4 days 2009: 9 days 2010: 12 days 2011: 3 days 2012: 8 days 2013: 3 days 2014: 2 days 2015: 6 days 2016: 4 days 2017: 1 days 2018: 5 days 2019: 1 days 2020: 3 days 2021: 8 days 2022: 0 days 2023: 30 days 2024: 6 days 2025: 11 days
Columbus
Columbus, OH · 2025: 3 unhealthy days by the 2010
rules, 8 by today's. EPA printed 6 for 2010.
Columbus: unhealthy days by the 2010 rules
0
20
40
60
2000
2005
2010
2015
2020
2025
2000: 21 days 2001: 31 days 2002: 47 days 2003: 23 days 2004: 12 days 2005: 32 days 2006: 11 days 2007: 30 days 2008: 10 days 2009: 1 days 2010: 6 days 2011: 11 days 2012: 14 days 2013: 2 days 2014: 0 days 2015: 0 days 2016: 3 days 2017: 0 days 2018: 1 days 2019: 0 days 2020: 0 days 2021: 0 days 2022: 1 days 2023: 8 days 2024: 2 days 2025: 3 days
Columbus: unhealthy days by today's rules
0
20
40
60
2000
2005
2010
2015
2020
2025
2000: 41 days 2001: 50 days 2002: 62 days 2003: 35 days 2004: 29 days 2005: 50 days 2006: 27 days 2007: 47 days 2008: 22 days 2009: 5 days 2010: 23 days 2011: 21 days 2012: 29 days 2013: 6 days 2014: 7 days 2015: 5 days 2016: 10 days 2017: 3 days 2018: 3 days 2019: 1 days 2020: 3 days 2021: 0 days 2022: 3 days 2023: 13 days 2024: 5 days 2025: 8 days
Indianapolis
Indianapolis-Carmel-Anderson, IN · 2025: 4 unhealthy days by the 2010
rules, 8 by today's. EPA printed 9 for 2010.
Indianapolis: unhealthy days by the 2010 rules
0
20
40
60
80
100
2000
2005
2010
2015
2020
2025
2000: 79 days 2001: 41 days 2002: 46 days 2003: 28 days 2004: 10 days 2005: 39 days 2006: 15 days 2007: 36 days 2008: 5 days 2009: 6 days 2010: 7 days 2011: 13 days 2012: 19 days 2013: 4 days 2014: 5 days 2015: 2 days 2016: 3 days 2017: 2 days 2018: 10 days 2019: 1 days 2020: 2 days 2021: 1 days 2022: 8 days 2023: 20 days 2024: 2 days 2025: 4 days
Indianapolis: unhealthy days by today's rules
0
20
40
60
80
100
2000
2005
2010
2015
2020
2025
2000: 98 days 2001: 62 days 2002: 56 days 2003: 48 days 2004: 29 days 2005: 58 days 2006: 27 days 2007: 55 days 2008: 13 days 2009: 13 days 2010: 23 days 2011: 29 days 2012: 29 days 2013: 7 days 2014: 8 days 2015: 4 days 2016: 12 days 2017: 7 days 2018: 13 days 2019: 5 days 2020: 7 days 2021: 7 days 2022: 15 days 2023: 24 days 2024: 4 days 2025: 8 days
Cleveland
Cleveland-Elyria, OH · 2025: 1 unhealthy days by the 2010
rules, 7 by today's. EPA printed 22 for 2010.
Cleveland: unhealthy days by the 2010 rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 28 days 2001: 49 days 2002: 42 days 2003: 25 days 2004: 23 days 2005: 47 days 2006: 19 days 2007: 14 days 2008: 12 days 2009: 4 days 2010: 23 days 2011: 15 days 2012: 32 days 2013: 2 days 2014: 5 days 2015: 2 days 2016: 6 days 2017: 2 days 2018: 5 days 2019: 1 days 2020: 4 days 2021: 1 days 2022: 6 days 2023: 11 days 2024: 3 days 2025: 1 days
Cleveland: unhealthy days by today's rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 54 days 2001: 74 days 2002: 56 days 2003: 49 days 2004: 38 days 2005: 66 days 2006: 27 days 2007: 29 days 2008: 25 days 2009: 13 days 2010: 41 days 2011: 29 days 2012: 48 days 2013: 6 days 2014: 10 days 2015: 11 days 2016: 14 days 2017: 6 days 2018: 13 days 2019: 7 days 2020: 11 days 2021: 8 days 2022: 8 days 2023: 16 days 2024: 9 days 2025: 7 days
Memphis
Memphis, TN-MS-AR · 2025: 4 unhealthy days by the 2010
rules, 7 by today's. EPA printed 13 for 2010.
Memphis: unhealthy days by the 2010 rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 53 days 2001: 34 days 2002: 34 days 2003: 29 days 2004: 14 days 2005: 49 days 2006: 33 days 2007: 39 days 2008: 10 days 2009: 4 days 2010: 14 days 2011: 22 days 2012: 20 days 2013: 1 days 2014: 2 days 2015: 1 days 2016: 2 days 2017: 1 days 2018: 3 days 2019: 2 days 2020: 1 days 2021: 4 days 2022: 6 days 2023: 5 days 2024: 5 days 2025: 4 days
Memphis: unhealthy days by today's rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 68 days 2001: 58 days 2002: 49 days 2003: 47 days 2004: 28 days 2005: 74 days 2006: 50 days 2007: 52 days 2008: 24 days 2009: 9 days 2010: 24 days 2011: 35 days 2012: 37 days 2013: 5 days 2014: 4 days 2015: 5 days 2016: 8 days 2017: 4 days 2018: 11 days 2019: 5 days 2020: 4 days 2021: 7 days 2022: 13 days 2023: 14 days 2024: 11 days 2025: 7 days
Washington
Washington-Arlington-Alexandria, DC-VA-MD-WV · 2025: 4 unhealthy days by the 2010
rules, 7 by today's. EPA printed 30 for 2010.
Washington: unhealthy days by the 2010 rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 43 days 2001: 50 days 2002: 59 days 2003: 28 days 2004: 27 days 2005: 46 days 2006: 37 days 2007: 45 days 2008: 23 days 2009: 6 days 2010: 35 days 2011: 21 days 2012: 22 days 2013: 4 days 2014: 4 days 2015: 5 days 2016: 9 days 2017: 3 days 2018: 5 days 2019: 4 days 2020: 1 days 2021: 4 days 2022: 3 days 2023: 9 days 2024: 4 days 2025: 4 days
Washington: unhealthy days by today's rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 64 days 2001: 78 days 2002: 81 days 2003: 48 days 2004: 41 days 2005: 60 days 2006: 55 days 2007: 66 days 2008: 39 days 2009: 13 days 2010: 50 days 2011: 39 days 2012: 36 days 2013: 12 days 2014: 10 days 2015: 14 days 2016: 16 days 2017: 8 days 2018: 10 days 2019: 11 days 2020: 3 days 2021: 10 days 2022: 4 days 2023: 20 days 2024: 8 days 2025: 7 days
Atlanta
Atlanta-Sandy Springs-Roswell, GA · 2025: 1 unhealthy days by the 2010
rules, 6 by today's. EPA printed 27 for 2010.
Atlanta: unhealthy days by the 2010 rules
0
30
60
90
120
2000
2005
2010
2015
2020
2025
2000: 88 days 2001: 62 days 2002: 60 days 2003: 38 days 2004: 34 days 2005: 51 days 2006: 64 days 2007: 57 days 2008: 32 days 2009: 15 days 2010: 27 days 2011: 44 days 2012: 18 days 2013: 3 days 2014: 8 days 2015: 7 days 2016: 15 days 2017: 7 days 2018: 2 days 2019: 10 days 2020: 1 days 2021: 2 days 2022: 4 days 2023: 13 days 2024: 8 days 2025: 1 days
Atlanta: unhealthy days by today's rules
0
30
60
90
120
2000
2005
2010
2015
2020
2025
2000: 115 days 2001: 82 days 2002: 71 days 2003: 57 days 2004: 52 days 2005: 68 days 2006: 86 days 2007: 83 days 2008: 53 days 2009: 24 days 2010: 47 days 2011: 67 days 2012: 28 days 2013: 13 days 2014: 18 days 2015: 16 days 2016: 32 days 2017: 11 days 2018: 10 days 2019: 19 days 2020: 3 days 2021: 8 days 2022: 9 days 2023: 21 days 2024: 14 days 2025: 6 days
Baltimore
Baltimore-Columbia-Towson, MD · 2025: 3 unhealthy days by the 2010
rules, 5 by today's. EPA printed 33 for 2010.
Baltimore: unhealthy days by the 2010 rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 40 days 2001: 52 days 2002: 62 days 2003: 32 days 2004: 31 days 2005: 38 days 2006: 34 days 2007: 45 days 2008: 23 days 2009: 11 days 2010: 33 days 2011: 24 days 2012: 20 days 2013: 4 days 2014: 4 days 2015: 6 days 2016: 13 days 2017: 8 days 2018: 4 days 2019: 10 days 2020: 1 days 2021: 6 days 2022: 1 days 2023: 7 days 2024: 2 days 2025: 3 days
Baltimore: unhealthy days by today's rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 59 days 2001: 75 days 2002: 82 days 2003: 51 days 2004: 49 days 2005: 58 days 2006: 53 days 2007: 63 days 2008: 42 days 2009: 21 days 2010: 53 days 2011: 37 days 2012: 35 days 2013: 10 days 2014: 5 days 2015: 15 days 2016: 24 days 2017: 15 days 2018: 16 days 2019: 13 days 2020: 3 days 2021: 15 days 2022: 2 days 2023: 17 days 2024: 12 days 2025: 5 days
Boston
Boston-Cambridge-Newton, MA-NH · 2025: 2 unhealthy days by the 2010
rules, 5 by today's. EPA printed 5 for 2010.
Boston: unhealthy days by the 2010 rules
0
10
20
30
40
50
60
2000
2005
2010
2015
2020
2025
2000: 6 days 2001: 26 days 2002: 43 days 2003: 16 days 2004: 8 days 2005: 27 days 2006: 16 days 2007: 25 days 2008: 9 days 2009: 5 days 2010: 5 days 2011: 3 days 2012: 6 days 2013: 5 days 2014: 0 days 2015: 1 days 2016: 2 days 2017: 3 days 2018: 1 days 2019: 1 days 2020: 0 days 2021: 3 days 2022: 1 days 2023: 4 days 2024: 5 days 2025: 2 days
Boston: unhealthy days by today's rules
0
10
20
30
40
50
60
2000
2005
2010
2015
2020
2025
2000: 18 days 2001: 36 days 2002: 58 days 2003: 28 days 2004: 15 days 2005: 34 days 2006: 32 days 2007: 35 days 2008: 17 days 2009: 7 days 2010: 10 days 2011: 7 days 2012: 13 days 2013: 9 days 2014: 5 days 2015: 4 days 2016: 7 days 2017: 5 days 2018: 5 days 2019: 1 days 2020: 0 days 2021: 5 days 2022: 6 days 2023: 7 days 2024: 5 days 2025: 5 days
Pittsburgh
Pittsburgh, PA · 2025: 2 unhealthy days by the 2010
rules, 5 by today's. EPA printed 58 for 2010.
Pittsburgh: unhealthy days by the 2010 rules
0
20
40
60
80
100
2000
2005
2010
2015
2020
2025
2000: 40 days 2001: 63 days 2002: 65 days 2003: 45 days 2004: 44 days 2005: 57 days 2006: 51 days 2007: 60 days 2008: 42 days 2009: 20 days 2010: 43 days 2011: 23 days 2012: 31 days 2013: 8 days 2014: 6 days 2015: 12 days 2016: 12 days 2017: 7 days 2018: 7 days 2019: 9 days 2020: 6 days 2021: 4 days 2022: 6 days 2023: 12 days 2024: 1 days 2025: 2 days
Pittsburgh: unhealthy days by today's rules
0
20
40
60
80
100
2000
2005
2010
2015
2020
2025
2000: 63 days 2001: 92 days 2002: 78 days 2003: 64 days 2004: 65 days 2005: 85 days 2006: 72 days 2007: 73 days 2008: 60 days 2009: 36 days 2010: 61 days 2011: 47 days 2012: 47 days 2013: 18 days 2014: 12 days 2015: 26 days 2016: 28 days 2017: 19 days 2018: 15 days 2019: 12 days 2020: 12 days 2021: 9 days 2022: 11 days 2023: 24 days 2024: 10 days 2025: 5 days
Sacramento
Sacramento--Roseville--Arden-Arcade, CA · 2025: 4 unhealthy days by the 2010
rules, 5 by today's. EPA printed 23 for 2010.
Sacramento: unhealthy days by the 2010 rules
0
40
80
120
160
2000
2005
2010
2015
2020
2025
2000: 77 days 2001: 92 days 2002: 116 days 2003: 87 days 2004: 79 days 2005: 73 days 2006: 93 days 2007: 67 days 2008: 66 days 2009: 52 days 2010: 25 days 2011: 56 days 2012: 50 days 2013: 27 days 2014: 34 days 2015: 18 days 2016: 33 days 2017: 22 days 2018: 40 days 2019: 11 days 2020: 38 days 2021: 43 days 2022: 18 days 2023: 7 days 2024: 16 days 2025: 4 days
Sacramento: unhealthy days by today's rules
0
40
80
120
160
2000
2005
2010
2015
2020
2025
2000: 104 days 2001: 112 days 2002: 145 days 2003: 111 days 2004: 112 days 2005: 92 days 2006: 120 days 2007: 96 days 2008: 89 days 2009: 69 days 2010: 42 days 2011: 78 days 2012: 79 days 2013: 49 days 2014: 57 days 2015: 40 days 2016: 58 days 2017: 56 days 2018: 56 days 2019: 20 days 2020: 50 days 2021: 58 days 2022: 41 days 2023: 14 days 2024: 35 days 2025: 5 days
Birmingham
Birmingham-Hoover, AL · 2025: 1 unhealthy days by the 2010
rules, 2 by today's. EPA printed 15 for 2010.
Birmingham: unhealthy days by the 2010 rules
0
30
60
90
120
2000
2005
2010
2015
2020
2025
2000: 84 days 2001: 87 days 2002: 41 days 2003: 27 days 2004: 21 days 2005: 45 days 2006: 47 days 2007: 49 days 2008: 16 days 2009: 5 days 2010: 15 days 2011: 21 days 2012: 10 days 2013: 1 days 2014: 1 days 2015: 3 days 2016: 5 days 2017: 2 days 2018: 2 days 2019: 3 days 2020: 2 days 2021: 3 days 2022: 0 days 2023: 9 days 2024: 2 days 2025: 1 days
Birmingham: unhealthy days by today's rules
0
30
60
90
120
2000
2005
2010
2015
2020
2025
2000: 108 days 2001: 104 days 2002: 67 days 2003: 50 days 2004: 42 days 2005: 67 days 2006: 75 days 2007: 74 days 2008: 30 days 2009: 7 days 2010: 30 days 2011: 38 days 2012: 20 days 2013: 3 days 2014: 5 days 2015: 6 days 2016: 11 days 2017: 3 days 2018: 4 days 2019: 15 days 2020: 3 days 2021: 5 days 2022: 3 days 2023: 20 days 2024: 6 days 2025: 2 days
New Orleans
New Orleans-Metairie, LA · 2025: 0 unhealthy days by the 2010
rules, 2 by today's. EPA printed 8 for 2010.
New Orleans: unhealthy days by the 2010 rules
0
20
40
60
2000
2005
2010
2015
2020
2025
2000: 34 days 2001: 20 days 2002: 7 days 2003: 16 days 2004: 13 days 2005: 18 days 2006: 15 days 2007: 17 days 2008: 5 days 2009: 7 days 2010: 8 days 2011: 15 days 2012: 9 days 2013: 3 days 2014: 6 days 2015: 0 days 2016: 2 days 2017: 2 days 2018: 0 days 2019: 0 days 2020: 0 days 2021: 0 days 2022: 0 days 2023: 2 days 2024: 1 days 2025: 0 days
New Orleans: unhealthy days by today's rules
0
20
40
60
2000
2005
2010
2015
2020
2025
2000: 66 days 2001: 30 days 2002: 16 days 2003: 25 days 2004: 21 days 2005: 34 days 2006: 31 days 2007: 25 days 2008: 14 days 2009: 13 days 2010: 16 days 2011: 29 days 2012: 17 days 2013: 5 days 2014: 13 days 2015: 3 days 2016: 4 days 2017: 2 days 2018: 5 days 2019: 1 days 2020: 0 days 2021: 3 days 2022: 3 days 2023: 10 days 2024: 6 days 2025: 2 days
Orlando
Orlando-Kissimmee-Sanford, FL · 2025: 0 unhealthy days by the 2010
rules, 2 by today's. EPA printed 2 for 2010.
Orlando: unhealthy days by the 2010 rules
0
8
16
24
32
2000
2005
2010
2015
2020
2025
2000: 16 days 2001: 15 days 2002: 7 days 2003: 8 days 2004: 6 days 2005: 10 days 2006: 9 days 2007: 12 days 2008: 2 days 2009: 1 days 2010: 2 days 2011: 8 days 2012: 1 days 2013: 0 days 2014: 1 days 2015: 0 days 2016: 0 days 2017: 2 days 2018: 2 days 2019: 1 days 2020: 0 days 2021: 0 days 2022: 0 days 2023: 1 days 2024: 1 days 2025: 0 days
Orlando: unhealthy days by today's rules
0
8
16
24
32
2000
2005
2010
2015
2020
2025
2000: 33 days 2001: 20 days 2002: 12 days 2003: 15 days 2004: 14 days 2005: 21 days 2006: 23 days 2007: 18 days 2008: 6 days 2009: 3 days 2010: 7 days 2011: 12 days 2012: 7 days 2013: 3 days 2014: 2 days 2015: 1 days 2016: 1 days 2017: 3 days 2018: 3 days 2019: 5 days 2020: 0 days 2021: 0 days 2022: 0 days 2023: 3 days 2024: 3 days 2025: 2 days
Portland
Portland-Vancouver-Hillsboro, OR-WA · 2025: 1 unhealthy days by the 2010
rules, 2 by today's. EPA printed 1 for 2010.
Portland: unhealthy days by the 2010 rules
0
6
12
18
24
2000
2005
2010
2015
2020
2025
2000: 7 days 2001: 7 days 2002: 7 days 2003: 2 days 2004: 6 days 2005: 10 days 2006: 7 days 2007: 11 days 2008: 7 days 2009: 6 days 2010: 1 days 2011: 11 days 2012: 1 days 2013: 12 days 2014: 3 days 2015: 4 days 2016: 0 days 2017: 13 days 2018: 6 days 2019: 1 days 2020: 12 days 2021: 1 days 2022: 5 days 2023: 4 days 2024: 5 days 2025: 1 days
Portland: unhealthy days by today's rules
0
6
12
18
24
2000
2005
2010
2015
2020
2025
2000: 12 days 2001: 9 days 2002: 10 days 2003: 9 days 2004: 14 days 2005: 15 days 2006: 14 days 2007: 22 days 2008: 9 days 2009: 17 days 2010: 3 days 2011: 17 days 2012: 3 days 2013: 16 days 2014: 8 days 2015: 7 days 2016: 2 days 2017: 16 days 2018: 11 days 2019: 3 days 2020: 14 days 2021: 1 days 2022: 7 days 2023: 6 days 2024: 6 days 2025: 2 days
Tampa
Tampa-St. Petersburg-Clearwater, FL · 2025: 2 unhealthy days by the 2010
rules, 2 by today's. EPA printed 11 for 2010.
Tampa: unhealthy days by the 2010 rules
0
10
20
30
40
50
2000
2005
2010
2015
2020
2025
2000: 33 days 2001: 20 days 2002: 6 days 2003: 14 days 2004: 14 days 2005: 24 days 2006: 23 days 2007: 14 days 2008: 7 days 2009: 4 days 2010: 2 days 2011: 7 days 2012: 3 days 2013: 1 days 2014: 0 days 2015: 1 days 2016: 1 days 2017: 3 days 2018: 2 days 2019: 1 days 2020: 0 days 2021: 1 days 2022: 1 days 2023: 1 days 2024: 2 days 2025: 2 days
Tampa: unhealthy days by today's rules
0
10
20
30
40
50
2000
2005
2010
2015
2020
2025
2000: 52 days 2001: 30 days 2002: 14 days 2003: 28 days 2004: 20 days 2005: 40 days 2006: 40 days 2007: 20 days 2008: 11 days 2009: 5 days 2010: 10 days 2011: 16 days 2012: 9 days 2013: 4 days 2014: 6 days 2015: 1 days 2016: 3 days 2017: 3 days 2018: 5 days 2019: 5 days 2020: 3 days 2021: 1 days 2022: 1 days 2023: 5 days 2024: 5 days 2025: 2 days
Miami
Miami-Fort Lauderdale-West Palm Beach, FL · 2025: 0 unhealthy days by the 2010
rules, 1 by today's. EPA printed 4 for 2010.
Miami: unhealthy days by the 2010 rules
0
5
10
15
20
2000
2005
2010
2015
2020
2025
2000: 15 days 2001: 6 days 2002: 3 days 2003: 3 days 2004: 6 days 2005: 2 days 2006: 8 days 2007: 10 days 2008: 5 days 2009: 1 days 2010: 3 days 2011: 5 days 2012: 2 days 2013: 2 days 2014: 2 days 2015: 0 days 2016: 5 days 2017: 3 days 2018: 2 days 2019: 1 days 2020: 2 days 2021: 2 days 2022: 1 days 2023: 4 days 2024: 3 days 2025: 0 days
Miami: unhealthy days by today's rules
0
5
10
15
20
2000
2005
2010
2015
2020
2025
2000: 19 days 2001: 12 days 2002: 5 days 2003: 5 days 2004: 9 days 2005: 9 days 2006: 12 days 2007: 13 days 2008: 8 days 2009: 3 days 2010: 5 days 2011: 9 days 2012: 4 days 2013: 5 days 2014: 5 days 2015: 1 days 2016: 6 days 2017: 8 days 2018: 4 days 2019: 2 days 2020: 2 days 2021: 3 days 2022: 2 days 2023: 4 days 2024: 4 days 2025: 1 days
Nashville
Nashville-Davidson--Murfreesboro--Franklin, TN · 2025: 1 unhealthy days by the 2010
rules, 1 by today's. EPA printed 10 for 2010.
Nashville: unhealthy days by the 2010 rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 53 days 2001: 26 days 2002: 38 days 2003: 23 days 2004: 7 days 2005: 30 days 2006: 18 days 2007: 38 days 2008: 11 days 2009: 1 days 2010: 10 days 2011: 13 days 2012: 22 days 2013: 0 days 2014: 1 days 2015: 0 days 2016: 4 days 2017: 1 days 2018: 2 days 2019: 0 days 2020: 1 days 2021: 3 days 2022: 3 days 2023: 4 days 2024: 5 days 2025: 1 days
Nashville: unhealthy days by today's rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 76 days 2001: 47 days 2002: 54 days 2003: 43 days 2004: 22 days 2005: 55 days 2006: 36 days 2007: 70 days 2008: 24 days 2009: 3 days 2010: 28 days 2011: 20 days 2012: 31 days 2013: 1 days 2014: 6 days 2015: 1 days 2016: 6 days 2017: 1 days 2018: 6 days 2019: 1 days 2020: 2 days 2021: 5 days 2022: 4 days 2023: 10 days 2024: 7 days 2025: 1 days
Seattle
Seattle-Tacoma-Bellevue, WA · 2025: 1 unhealthy days by the 2010
rules, 1 by today's. EPA printed 1 for 2010.
Seattle: unhealthy days by the 2010 rules
0
10
20
30
40
2000
2005
2010
2015
2020
2025
2000: 22 days 2001: 15 days 2002: 17 days 2003: 24 days 2004: 14 days 2005: 12 days 2006: 22 days 2007: 17 days 2008: 7 days 2009: 14 days 2010: 1 days 2011: 8 days 2012: 6 days 2013: 3 days 2014: 3 days 2015: 9 days 2016: 2 days 2017: 18 days 2018: 14 days 2019: 2 days 2020: 12 days 2021: 4 days 2022: 17 days 2023: 4 days 2024: 2 days 2025: 1 days
Seattle: unhealthy days by today's rules
0
10
20
30
40
2000
2005
2010
2015
2020
2025
2000: 28 days 2001: 27 days 2002: 23 days 2003: 40 days 2004: 22 days 2005: 25 days 2006: 29 days 2007: 26 days 2008: 10 days 2009: 24 days 2010: 3 days 2011: 13 days 2012: 12 days 2013: 8 days 2014: 7 days 2015: 17 days 2016: 3 days 2017: 24 days 2018: 16 days 2019: 2 days 2020: 14 days 2021: 7 days 2022: 33 days 2023: 7 days 2024: 4 days 2025: 1 days
Charlotte
Charlotte-Concord-Gastonia, NC-SC · 2025: 0 unhealthy days by the 2010
rules, 0 by today's. EPA printed 14 for 2010.
Charlotte: unhealthy days by the 2010 rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 60 days 2001: 58 days 2002: 64 days 2003: 26 days 2004: 21 days 2005: 46 days 2006: 37 days 2007: 56 days 2008: 29 days 2009: 6 days 2010: 17 days 2011: 24 days 2012: 14 days 2013: 0 days 2014: 0 days 2015: 2 days 2016: 4 days 2017: 0 days 2018: 1 days 2019: 5 days 2020: 0 days 2021: 1 days 2022: 2 days 2023: 4 days 2024: 1 days 2025: 0 days
Charlotte: unhealthy days by today's rules
0
20
40
60
80
2000
2005
2010
2015
2020
2025
2000: 80 days 2001: 80 days 2002: 76 days 2003: 49 days 2004: 42 days 2005: 68 days 2006: 57 days 2007: 82 days 2008: 49 days 2009: 10 days 2010: 38 days 2011: 45 days 2012: 26 days 2013: 3 days 2014: 5 days 2015: 11 days 2016: 9 days 2017: 5 days 2018: 10 days 2019: 17 days 2020: 2 days 2021: 3 days 2022: 3 days 2023: 8 days 2024: 5 days 2025: 0 days
San Francisco
San Francisco-Oakland-Hayward, CA · 2025: 0 unhealthy days by the 2010
rules, 0 by today's. EPA printed 4 for 2010.
San Francisco: unhealthy days by the 2010 rules
0
10
20
30
40
2000
2005
2010
2015
2020
2025
2000: 18 days 2001: 24 days 2002: 34 days 2003: 15 days 2004: 15 days 2005: 10 days 2006: 24 days 2007: 8 days 2008: 12 days 2009: 9 days 2010: 7 days 2011: 5 days 2012: 4 days 2013: 3 days 2014: 5 days 2015: 6 days 2016: 8 days 2017: 13 days 2018: 17 days 2019: 4 days 2020: 20 days 2021: 4 days 2022: 2 days 2023: 10 days 2024: 0 days 2025: 0 days (incomplete monitoring)
San Francisco: unhealthy days by today's rules
0
10
20
30
40
2000
2005
2010
2015
2020
2025
2000: 29 days 2001: 32 days 2002: 42 days 2003: 26 days 2004: 25 days 2005: 21 days 2006: 29 days 2007: 15 days 2008: 20 days 2009: 17 days 2010: 14 days 2011: 12 days 2012: 7 days 2013: 9 days 2014: 10 days 2015: 14 days 2016: 15 days 2017: 16 days 2018: 18 days 2019: 9 days 2020: 22 days 2021: 10 days 2022: 5 days 2023: 14 days 2024: 1 days 2025: 0 days (incomplete monitoring)
Combined totals
Year 2010 rules Today's rules Difference
2000 1622 2292
+670 2001 1611 2282
+671 2002 1615 2156
+541 2003 1216 1821
+605 2004 944 1475
+531 2005 1431 2056
+625 2006 1406 1986
+580 2007 1448 2031
+583 2008 930 1407
+477 2009 543 853
+310 2010 684 1160
+476 2011 841 1335
+494 2012 835 1335
+500 2013 435 738
+303 2014 388 685
+297 2015 397 741
+344 2016 404 749
+345 2017 430 755
+325 2018 452 806
+354 2019 253 506
+253 2020 571 794
+223 2021 547 834
+287 2022 367 650
+283 2023 506 846
+340 2024 475 799
+324 2025 321 540
+219
Sources
