Bad Air Days in Lyon County, Nevada: 3 a Year

3 bad air days a year

About the middle of monitored US counties. Ranked 372 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (24% particle days).

When the bad days come in Lyon

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

What actually helps 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

The worst recent year was 2021, with 7 bad days on 270 monitored days.

Date	AQI	Main pollutant
2020-09-17	328	PM10
2020-09-15	162	PM10
2020-11-06	160	PM10
2020-09-14	159	PM10
2020-09-08	149	PM10

The air on a normal day

Across 3,471 monitored days from 2016 to 2025, the air in Lyon County rated Good on 87% of them, more often than the 72% typical of monitored counties, and Moderate on 12%. The median day sat at AQI 40; one day in ten went above 55.

The pollutant setting the AQI on an ordinary day here:

ozone98%3,407 days
coarse dust (PM10)2%64 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	359	323	36	0	0	41	84
2024	349	310	39	0	0	42	90
2023	349	325	24	0	0	41	87
2022	355	329	25	1	0	39	105
2021	270	196	67	7	0	41	133
2020	356	308	39	9	4	38	328
2019	356	344	12	0	0	38	71
2018	362	304	50	8	0	40	133
2017	363	307	53	3	0	42	112
2016	352	282	69	1	0	41	101
2015	275	207	64	4	0	45	108
2014	212	147	63	2	0	47	112
2013	208	135	73	0	0	47	90
2012	212	130	77	5	0	47	119
2011	198	159	35	4	0	44	133
2010	192	167	24	1	0	37	101

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

Elsewhere in Nevada

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.