Barnwell County, South Carolina air quality history
Daily Air Quality Index summaries from EPA monitors in Barnwell, South Carolina, 1985–2007.
75%
Good days in 2007
40
Median daily AQI, 2007
9
Days above 100 in 2007
341
Days with an AQI in 2007 (of 365)
In 2007, EPA reported a daily Air Quality Index (AQI) for Barnwell, South Carolina on 341 days. 256 of those days (75%) were in the Good range, and the median daily AQI was 40. That median is lower than the typical monitored county in South Carolina (median 47 across 21 counties), and lower than the typical monitored U.S. county (46). The main pollutant was ozone on 250 days. Across the years with fuller monitoring, the share of Good days rose: an average of 69% in 1986–1988 versus 77% in 2005–2007.
The most recent year with data for this county is 2007; EPA's files for 2008–2025 contain no row for it, which usually means its monitors stopped reporting.
Years with fewer than 120 monitored days (1985) 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, 2007
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
Ozone
250
73%
Nitrogen dioxide (NO₂)
79
23%
Coarse particles (PM10)
12
4%
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
2007
341
256
76
9
0
0
0
40
74
119
Ozone
2006
364
271
86
7
0
0
0
39
77
126
Ozone
2005
365
300
58
7
0
0
0
35
71
115
Ozone
2004
364
291
65
8
0
0
0
35
67
129
Ozone
2003
365
310
50
5
0
0
0
32
61
126
Ozone
2002
364
282
62
14
6
0
0
36
80
164
Ozone
2001
349
271
70
6
2
0
0
39
77
182
Ozone
2000
343
228
84
25
6
0
0
41
97
185
Ozone
1999
357
262
62
28
5
0
0
38
93
174
Ozone
1998
353
228
75
38
12
0
0
43
115
190
Ozone
1997
335
244
67
22
2
0
0
36
90
174
Ozone
1996
348
278
58
12
0
0
0
31
77
140
Ozone
1995
323
290
31
2
0
0
0
19
51
119
Ozone
1994
343
294
37
10
2
0
0
34
64
177
Ozone
1993
340
242
77
21
0
0
0
38
87
147
Ozone
1992
324
263
48
11
2
0
0
33
71
154
Ozone
1991
313
246
56
8
3
0
0
35
77
166
Ozone
1990
327
201
89
27
10
0
0
44
108
197
Ozone
1989
300
238
49
13
0
0
0
33
80
150
Ozone
1988
337
230
63
34
9
1
0
40
108
202
Ozone
1987
338
246
62
23
7
0
0
37
100
174
Ozone
1986
290
188
74
24
4
0
0
45
100
166
Ozone
1985
29
29
0
0
0
0
0
30
39
40
Ozone
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 South Carolina with a similar median AQI in 2007
