Bad Air Days in Noble County, Ohio: under 1 a Year

under 1 bad air day a year

Rare: among the cleanest-air counties EPA monitors. Ranked 808 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (40% particle days).

When the bad days come in Noble

Most bad days here fall in June and April and July and September. Averaged over 2016 to 2025.

Is a purifier worth it here?

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.

Better or worse than it was

In 2000 to 2009 this county averaged 14 bad days a year; in 2016 to 2025, under 1. The air has improved. The worst recent year was 2023, with 3 bad days on 352 monitored days.

Date	AQI	Main pollutant
2023-06-29	207	PM2.5
2023-07-17	120	PM2.5
2023-06-01	112	Ozone
2016-04-18	105	Ozone
2016-09-23	105	Ozone

The air on a normal day

Across 3,537 monitored days from 2016 to 2025, the air in Noble County rated Good on 88% of them, more often than the 72% typical of monitored counties, and Moderate on 12%. The median day sat at AQI 38; one day in ten went above 53.

The pollutant setting the AQI on an ordinary day here:

ozone91%3,201 days
fine particles (PM2.5)9%336 days

Noble County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	362	311	51	0	0	37	90
2024	357	290	67	0	0	40	90
2023	352	307	42	3	1	39	207
2022	353	319	34	0	0	37	93
2021	351	307	44	0	0	37	84
2020	356	331	25	0	0	36	87
2019	361	325	36	0	0	38	87
2018	343	309	34	0	0	36	97
2017	354	309	45	0	0	38	97
2016	348	297	49	2	0	39	105
2015	360	296	63	1	0	38	112
2014	355	285	69	1	0	39	112
2013	348	285	62	1	0	38	108
2012	323	238	80	5	0	41	115
2011	304	243	61	0	0	41	97
2010	340	232	96	12	0	43	136

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

Elsewhere in Ohio

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, and on why a purifier does not touch ozone in smoke vs ozone.