Gaston County, North Carolina air quality history

Daily Air Quality Index summaries from EPA monitors in Gaston, North Carolina, 1992–2015.

64%

Good days in 2014

Median daily AQI, 2014

Days above 100 in 2014

351

Days with an AQI in 2014 (of 365)

In 2014, EPA reported a daily Air Quality Index (AQI) for Gaston, North Carolina on 351 days. 225 of those days (64%) were in the Good range, and the median daily AQI was 43. That median is about the same as the typical monitored county in North Carolina (median 44 across 44 counties), and about the same as the typical monitored U.S. county (42). The main pollutant was fine particles (PM2.5) on 351 days. Across the years with fuller monitoring, the share of Good days fell: an average of 99% in 1992–1994 versus 57% in 2012–2014.

The most recent year with data for this county is 2015; EPA's files for 2016–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1999, 2015) are shown in the table but left out of comparisons and trend statements.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Good
Moderate
Unhealthy for Sensitive Groups
Unhealthy
Very Unhealthy
Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median daily AQI
90th-percentile daily AQI

Main pollutant by day, 2014

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

Pollutant	Days as main pollutant	Share of monitored days
Fine particles (PM2.5)	351	100%

Year-by-year data

Annual AQI summary by year
Year	Days with AQI	Good	Moderate	Unhealthy for Sensitive Groups	Median AQI	90th pct.	Max AQI	Main pollutant
2015	36	29	7	0	38	55	65	PM2.5
2014	351	225	126	0	43	57	76	PM2.5
2013	328	210	118	0	42	57	70	PM2.5
2012	345	150	195	0	52	61	84	PM2.5
2011	345	139	206	0	53	66	90	PM2.5
2010	361	126	235	0	54	65	95	PM2.5
2009	360	158	202	0	52	64	89	PM2.5
2008	349	93	256	0	56	73	98	PM2.5
2007	330	89	240	1	57	78	123	PM2.5
2006	330	57	269	4	61	81	108	PM2.5
2005	120	27	92	1	59	81	121	PM2.5
2004	121	29	92	0	59	78	97	PM2.5
2003	120	32	87	1	59	77	115	PM2.5
2002	121	31	89	1	57	78	117	PM2.5
2001	121	31	89	1	58	74	111	PM2.5
2000	121	16	104	1	62	84	104	PM2.5
1999	117	28	88	1	59	88	109	PM2.5
1998	133	133	0	0	17	29	43	CO
1997	208	207	1	0	18	30	51	CO
1996	214	214	0	0	20	33	48	CO
1995	176	174	2	0	18	31	54	CO
1994	167	166	1	0	22	39	51	CO
1993	150	150	0	0	22	35	49	CO
1992	359	355	4	0	17	33	67	CO

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

Counties in North Carolina with a similar median AQI in 2014

All monitored counties in North Carolina

Source: U.S. EPA AirData, “Annual AQI by County” files for 1992–2015 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem