Bad Air Days in Lancaster County, Nebraska: under 1 a Year

under 1 bad air days a year

Rare: among the cleanest-air counties EPA monitors. Ranked 860 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (33% particle days).

When the bad days come in Lancaster

Most bad days here fall in June 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.

The record for Lancaster

In 2000 to 2009 this county averaged under 1 bad days a year; in 2016 to 2025, under 1. Not much has changed. The worst recent year was 2023, with 3 bad days on 283 monitored days.

Date	AQI	Main pollutant
2023-09-06	160	PM2.5
2023-06-07	108	Ozone
2023-06-06	101	Ozone
2023-06-28	100	Ozone
2017-04-08	97	Ozone

The air on a normal day

Across 2,790 monitored days from 2016 to 2025, the air in Lancaster County rated Good on 86% of them, more often than the 72% typical of monitored counties, and Moderate on 14%. The median day sat at AQI 38; one day in ten went above 53.

The pollutant setting the AQI on an ordinary day here:

ozone73%2,033 days
fine particles (PM2.5)27%757 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	281	240	41	0	0	37	87
2024	283	237	46	0	0	41	82
2023	283	197	83	3	1	42	160
2022	277	258	19	0	0	37	64
2021	276	246	30	0	0	37	84
2020	282	261	21	0	0	35	77
2019	288	249	39	0	0	36	70
2018	289	239	50	0	0	36	80
2017	270	235	35	0	0	37	97
2016	261	231	30	0	0	37	74
2015	261	220	41	0	0	40	80
2014	265	220	44	1	0	39	109
2013	257	219	38	0	0	38	77
2012	286	225	61	0	0	41	82
2011	365	320	45	0	0	30	88
2010	359	317	41	1	0	30	108

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

Elsewhere in Nebraska

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.