Bad Air Days in Caldwell County, North Carolina: 0 a Year

0 bad air days a year

Rare: among the cleanest-air counties EPA monitors. Ranked 969 of 996 monitored counties, where 1 is worst.

What to buy, and what not to

Bad air days are rare here. A standard furnace filter is enough; no purifier needed for outdoor air.
On the odd bad day, check AirNow and keep windows shut.

The worst days on file

In 2000 to 2009 this county averaged 25 bad days a year; in 2016 to 2025, 0. The air has improved.

Date	AQI	Main pollutant
2023-04-20	97	Ozone
2023-06-06	97	Ozone
2018-06-09	93	Ozone
2023-06-16	93	Ozone
2016-04-20	90	Ozone

Most days, not the worst ones

Across 2,398 monitored days from 2016 to 2025, the air in Caldwell County rated Good on 91% of them, more often than the 72% typical of monitored counties, and Moderate on 9%. The median day sat at AQI 40; one day in ten went above 51.

The pollutant setting the AQI on an ordinary day here:

ozone100%2,398 days

Every recent year on file

Year	Days monitored	Good	Moderate	Over 100	Median AQI	Highest AQI
2025*	245	238	7	0	36	77
2024	237	221	16	0	40	87
2023	245	220	25	0	40	97
2022	245	224	21	0	40	74
2021	243	219	24	0	40	77
2020	243	243	0	0	34	50
2019	243	214	29	0	42	74
2018	244	209	35	0	39	93
2017	239	209	30	0	42	90
2016	214	180	34	0	43	90
2015	207	173	34	0	42	97
2014	211	194	17	0	38	100
2013	214	203	11	0	37	93
2012	214	182	31	1	42	129
2011	214	161	53	0	45	100
2010	212	149	59	4	44	122

*2025 may be a partial year in EPA's file.

North Carolina compared

How this is counted

A bad air day is a day the county's daily AQI from EPA AirData went above 100, the level where EPA tells children, older adults and people with asthma or heart disease to cut back outdoors. Monitors do not run every day, so yearly counts are scaled to 365 days. This is the record, not today's air: for that, check AirNow. More on the method in how the county numbers are made, on the AQI 100 line in what counts as a bad air day.