Bad Air Days in Trego County, Kansas: 2 a Year

2 bad air days a year

About the middle of monitored US counties. Ranked 491 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly particles: smoke and dust (71% particle days).

When the bad days come in Trego

Most bad days here fall in April and August and September and October. 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.

The record for Trego

In 2000 to 2009 this county averaged 7 bad days a year; in 2016 to 2025, 2. The air has improved. The worst recent year was 2021, with 6 bad days on 362 monitored days.

Date	AQI	Main pollutant
2021-12-15	318	PM10
2023-09-06	164	PM2.5
2022-10-23	154	PM10
2020-10-11	147	PM10
2021-08-01	143	PM2.5

Most days, not the worst ones

Across 3,640 monitored days from 2016 to 2025, the air in Trego County rated Good on 78% of them, more often than the 72% typical of monitored counties, and Moderate on 22%. The median day sat at AQI 41; one day in ten went above 59.

The pollutant setting the AQI on an ordinary day here:

ozone70%2,566 days
fine particles (PM2.5)27%996 days
coarse dust (PM10)2%65 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	364	275	88	1	0	41	116
2024	365	261	100	4	0	44	127
2023	365	211	149	5	1	47	164
2022	360	266	91	3	1	42	154
2021	362	248	108	6	1	43	318
2020	365	307	57	1	0	38	147
2019	364	310	54	0	0	37	99
2018	364	287	76	1	0	39	130
2017	365	334	31	0	0	36	84
2016	366	334	32	0	0	39	67
2015	358	297	60	1	0	41	128
2014	362	283	79	0	0	41	97
2013	363	295	68	0	0	40	93
2012	366	255	98	13	0	42	143
2011	365	252	102	11	0	43	133
2010	364	270	90	4	0	43	108

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

Elsewhere in Kansas

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.