Counties in New York by share of days with good air quality (US EPA AQI)

Columbia County had the highest share of days with good air quality (US EPA AQI) of 35 counties in 2001, at 100%. Bronx County had the lowest, at 25.6%. The median was 69.4%. Source: EPA.

Highest100Columbia County

Lowest25.6Bronx County

Median69.435 counties

Map of counties, 2001

Under 55
55 to 68
68 to 69
69 to 74
74 to 85
85 and over
No data

%, 2001. Hatched areas have no value for this period. Source: Invokely calculation with data from EPA. Boundaries: U.S. Census Bureau cartographic boundary files.

All counties, 2001

%. Source: Invokely calculation with data from EPA. Retrieved 2026-10-12.

Full ranking

Rank	Counties	2001 (%)	Change on 2000
1	Columbia County	100	0 pts
1	Franklin County	100	0 pts
1	Rensselaer County	100	n/a
4	Herkimer County	90.1	-5.3 pts
5	Wayne County	87.6	-4 pts
6	Hamilton County	85.4	-6 pts
7	Saratoga County	84.3	-7.4 pts
8	Ulster County	81.9	-4.8 pts
9	Madison County	79.7	-9.9 pts
10	Chemung County	78.9	-9.8 pts
11	Tompkins County	75.8	-9.5 pts
12	Schenectady County	75.1	-7.4 pts
13	Albany County	71.2	-4.8 pts
14	Monroe County	71	-6.9 pts
15	Kings County	70.9	-1.7 pts
16	Oneida County	70.4	-9.3 pts
17	Niagara County	69.9	-3.6 pts
18	St. Lawrence County	69.4	-6.3 pts
19	Chautauqua County	69.3	-0.4 pts
20	Onondaga County	69	-6.1 pts
21	Putnam County	68.7	-13.5 pts
22	Dutchess County	68.3	-7.9 pts
22	Nassau County	68.3	-3.8 pts
24	Essex County	68.2	-2.8 pts
25	Jefferson County	67.6	-21.5 pts
26	Westchester County	66.7	-9.4 pts
27	Suffolk County	64.1	-3.1 pts
28	Orange County	57.3	-6.3 pts
29	Erie County	55.6	-4.2 pts
30	Broome County	55	+10.4 pts
31	Steuben County	51.8	-9.2 pts
32	Richmond County	49.6	-1.9 pts
33	Queens County	41.4	-11.1 pts
34	New York County	26.6	+7.7 pts
35	Bronx County	25.6	-0.1 pts

Other periods

About this ranking

Days with a daily Air Quality Index of 0 to 50 (good) as a percentage of the days of the year with an AQI in a US county. Calculated by Invokely from the day counts in the EPA AirData annual summaries; both counts are stored with each value.

United States counties with air quality monitors only, about 1,000 of some 3,100 in recent years; a county without monitors has no value. The number of days with an AQI differs between counties because some monitors run only in the ozone season.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. 4 counties with data in other periods have no value for 2001 and are left out rather than filled from another source. Equal values share a rank.

How to cite

U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Environmental Protection Agency. (2026). EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts (Counties in New York by share of days with good air quality (US EPA AQI), 2001) [Data set]. Retrieved October 12, 2026, from https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual

MLA 9

EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts, Counties in New York by share of days with good air quality (US EPA AQI), 2001. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/rankings/good-air-quality-days-share/new-york-counties?period=2001. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Counties in New York by share of days with good air quality (US EPA AQI), 2001. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/rankings/good-air-quality-days-share/new-york-counties?period=2001.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts, Counties in New York by share of days with good air quality (US EPA AQI), 2001 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/rankings/good-air-quality-days-share/new-york-counties?period=2001 (Accessed: 12 October 2026).

BibTeX

@misc{environmental_counties_in_new_york_2001,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts: Counties in New York by share of days with good air quality (US EPA AQI), 2001}},
  year = {2026},
  howpublished = {Data set},
  url = {https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/new-york-counties?period=2001. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download\_files.html\#Annual. Retrieved 2026-10-12.},
}

RIS

TY  - DATA
AU  - U.S. Environmental Protection Agency
TI  - EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts: Counties in New York by share of days with good air quality (US EPA AQI), 2001
PY  - 2026
DA  - 2026/07/13
PB  - U.S. Environmental Protection Agency
DB  - Invokely
UR  - https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual
L2  - https://invokely.ai/rankings/good-air-quality-days-share/new-york-counties?period=2001
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/good-air-quality-days-share/new-york-counties?period=2001.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  -

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Questions

Which county has the highest share of days with good air quality (US EPA AQI)?

Columbia County, with 100% in 2001, according to EPA.

Which county has the lowest share of days with good air quality (US EPA AQI)?

Bronx County, with 25.6% in 2001.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: good days as a share of days with an AQI, calculated with stored counts. Retrieved 2026-10-12. 4 counties have no value for 2001 and are not ranked.