Daily Air Quality Index summaries from EPA monitors in Harney, Oregon, 2000–2025.
72%
Good days in 2025
28
Median daily AQI, 2025
0
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Harney, Oregon on 365 days. 261 of those days (72%) were in the Good range, and the median daily AQI was 28. That median is about the same as the typical monitored county in Oregon (median 29 across 21 counties), and lower than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 365 days. Across the years with fuller monitoring, the share of Good days fell: an average of 64% in 2004–2006 versus 62% in 2023–2025.
Years with fewer than 120 monitored days (2000, 2001, 2002, 2003) are shown in the table but left out of comparisons and trend statements.
How the days broke down each year
Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.
Good
Moderate
Unhealthy for Sensitive Groups
Unhealthy
Very Unhealthy
Hazardous
Typical and high-end AQI over time
The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.
Median daily AQI
90th-percentile daily AQI
Main pollutant by day, 2025
On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.
Pollutant
Days as main pollutant
Share of monitored days
Fine particles (PM2.5)
365
100%
Year-by-year data
Annual AQI summary by year
Year
Days with AQI
Good
Moderate
Unhealthy for Sensitive Groups
Unhealthy
Very Unhealthy
Hazardous
Median AQI
90th pct.
Max AQI
Main pollutant
2025
365
261
104
0
0
0
0
28
60
93
PM2.5
2024
365
200
139
6
16
4
0
46
85
271
PM2.5
2023
365
214
150
1
0
0
0
43
67
117
PM2.5
2022
365
226
137
2
0
0
0
41
70
114
PM2.5
2021
365
191
165
5
4
0
0
48
71
185
PM2.5
2020
366
211
144
2
7
1
1
42
75
357
PM2.5
2019
364
204
155
5
0
0
0
44
70
131
PM2.5
2018
362
220
136
4
2
0
0
39
70
174
PM2.5
2017
365
203
154
6
2
0
0
43
74
175
PM2.5
2016
357
247
109
1
0
0
0
24
70
115
PM2.5
2015
365
240
122
3
0
0
0
35
67
126
PM2.5
2014
365
231
129
3
2
0
0
37
70
164
PM2.5
2013
363
215
140
8
0
0
0
44
76
142
PM2.5
2012
365
224
140
1
0
0
0
39
67
135
PM2.5
2011
363
218
140
5
0
0
0
37
79
134
PM2.5
2010
355
221
132
2
0
0
0
33
73
118
PM2.5
2009
360
214
146
0
0
0
0
39
72
96
PM2.5
2008
360
179
173
7
1
0
0
51
77
153
PM2.5
2007
344
209
128
6
1
0
0
36
75
169
PM2.5
2006
361
223
132
5
1
0
0
38
71
156
PM2.5
2005
359
235
121
3
0
0
0
32
75
112
PM2.5
2004
364
238
123
2
1
0
0
33
70
155
PM2.5
2003
60
49
11
0
0
0
0
29
59
87
PM2.5
2002
61
42
18
1
0
0
0
38
68
102
PM2.5
2001
60
41
18
1
0
0
0
32
77
109
PM2.5
2000
46
28
16
2
0
0
0
36
71
106
PM2.5
What this data can and can’t tell you
It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.
It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.
Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.
Counties in Oregon with a similar median AQI in 2025
