Merced, California Air Quality

Merced County, California (CA)

↓ Improvingover 10 years

Air Quality Grade

57/100

Current Median AQI

Moderate

5-Year Avg AQI

-10

10-Year Change

Better

Unhealthy Days/yr

5-year average

Ozone

Primary Pollutant

Ground-Level Ozone

10-Year AQI Trend

The solid line shows the median AQI each year. The dashed line shows the 90th percentile (worst 10% of days). This area has seen measurable air quality improvement over the decade.

Air Quality Day Breakdown

Number of days per year in each EPA AQI category. Green = Good (AQI 0-50), Yellow = Moderate (51-100), Orange = Unhealthy for Sensitive Groups (101-150), Red = Unhealthy or worse (151+).

Year-by-Year Data

Year	Median AQI	90th Pct	Max AQI	Good Days	Moderate	Unhealthy+	Pollutant
2023	51	87	129	171	179	15	Ozone
2022	56	87	143	140	212	13	Ozone
2021	54	100	166	155	177	33	Ozone
2020	57	96	194	131	203	32	PM2.5
2019	51	80	119	176	182	7	Ozone
2018	56	101	178	110	214	41	PM2.5
2017	58	100	161	127	203	34	PM2.5
2016	58	100	151	115	216	35	PM2.5
2015	61	105	159	107	213	45	Ozone
2014	61	113	157	120	186	58	Ozone

What This Means for Merced County Residents

Merced, California has received an Air Quality Grade of C (57/100) based on a decade of EPA monitoring data. The current median AQI of 51 falls in the "Moderate" range.

Encouragingly, air quality here has been improving, with the median AQI dropping by 10 points over the monitoring period. This trend suggests continued investment in emission controls and cleaner energy.

The primary pollutant affecting this area is Ground-Level Ozone. Over the past 5 years, this area has averaged 20 unhealthy air quality days per year — days when sensitive groups (children, elderly, those with respiratory conditions) should limit outdoor activity.