Bad Air Days in Sacramento County, California: 24 a Year

24 bad air days a year

Among the worst tenth of monitored US counties. Ranked 26 of 996 monitored counties, where 1 is worst.

What makes them bad: a mix of particles and ozone (43% particle days).

When the bad days come in Sacramento

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

What actually helps here

Particles (wildfire smoke, dust) cause enough bad days here to matter. A HEPA purifier sized to your bedroom removes them; run it with windows shut on bad days.
Upgrade the furnace or AC filter to MERV 13 so the whole house is filtered, not just one room.
Ozone drives many bad days here. Purifiers and filters do not remove ozone, so do not buy one for that. Ozone peaks on hot afternoons: exercise outside in the morning.
Sign up for EnviroFlash ozone alerts for this area during the worst months.

Better or worse than it was

In 2000 to 2009 this county averaged 78 bad days a year; in 2016 to 2025, 24. The air has improved. The worst recent year was 2016, with 39 bad days on 366 monitored days.

Date	AQI	Main pollutant
2021-08-28	381	PM2.5
2018-11-15	376	PM2.5
2018-11-11	350	PM2.5
2018-11-16	300	PM2.5
2018-11-14	278	PM2.5

Most days, not the worst ones

Across 3,653 monitored days from 2016 to 2025, the air in Sacramento County rated Good on 42% of them, less often than the 72% typical of monitored counties, and Moderate on 51%. The median day sat at AQI 54; one day in ten went above 92.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)50%1,827 days
ozone49%1,795 days
coarse dust (PM10)1%29 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	198	162	5	0	49	122
2024	366	182	169	15	0	51	140
2023	365	180	173	12	0	51	133
2022	365	162	184	19	2	53	164
2021	365	146	183	36	6	55	381
2020	366	145	185	36	19	55	226
2019	365	175	180	10	0	52	140
2018	365	104	226	35	13	58	376
2017	365	105	225	35	2	60	164
2016	366	136	191	39	6	55	172
2015	365	101	237	27	3	58	172
2014	365	133	192	40	0	55	147
2013	365	131	200	34	2	58	154
2012	366	152	157	57	11	56	201
2011	365	114	182	69	16	60	182
2010	365	161	176	28	8	53	207

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

Elsewhere in California

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.