Highest daily Air Quality Index (US EPA) in Calvert County

Highest daily Air Quality Index (US EPA) in Calvert County was 77 in 2025, according to the U.S. Environmental Protection Agency. That is down 31 from 2024. That is the 16th highest of 16 counties in 2025.

2025, index77
Change on 2024-31
Series high2062012
Series low672020

Next release: Tuesday, 13 July 2027, estimated by Invokely from past publication dates (low confidence), not announced by the publisher. Release calendar

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Highest daily Air Quality Index (US EPA) in Calvert County, 1996 to 2025

5010015020025019962000200720112015201920251996: 151 index1997: 177 index1998: 177 index1999: 192 index2000: 182 index2001: 164 index2005: 166 index2006: 161 index2007: 159 index2008: 154 index2009: 119 index2010: 182 index2011: 169 index2012: 206 index2013: 105 index2014: 105 index2015: 93 index2016: 115 index2017: 108 index2018: 147 index2019: 71 index2020: 67 index2021: 105 index2022: 74 index2023: 101 index2024: 108 index2025: 77 index5010015020025019962008201720251996: 151 index1997: 177 index1998: 177 index1999: 192 index2000: 182 index2001: 164 index2005: 166 index2006: 161 index2007: 159 index2008: 154 index2009: 119 index2010: 182 index2011: 169 index2012: 206 index2013: 105 index2014: 105 index2015: 93 index2016: 115 index2017: 108 index2018: 147 index2019: 71 index2020: 67 index2021: 105 index2022: 74 index2023: 101 index2024: 108 index2025: 77 index
index. Source: EPA, EPA AirData annual AQI by county: highest daily AQI. Retrieved 2026-10-12, published 2026-07-13.
All 27 values
Periodindex
202577
2024108
2023101
202274
2021105
202067
201971
2018147
2017108
2016115
201593
2014105
2013105
2012206
2011169
2010182
2009119
2008154
2007159
2006161
2005166
2001164
2000182
1999192
1998177
1997177
1996151

Calvert County compared with nearby places

Anne Arundel County: 119 indexBaltimore County: 129 indexCalvert County: 77 indexCarroll County: 90 indexCecil County: 129 indexCharles County: 97 indexDorchester County: 84 indexFrederick County: 93 indexGarrett County: 80 indexHarford County: 143 indexHoward County: 78 indexKent County: 129 indexMontgomery County: 90 indexPrince George's County: 126 indexWashington County: 90 indexBaltimore city: 136 index
  • Under 84
  • 84 to 90
  • 90 to 120
  • 120 to 130
  • 130 and over
  • No data
Highest daily Air Quality Index (US EPA), 2025, index. Calvert County is outlined. Same source and period for every area shown. Source: U.S. Environmental Protection Agency. Boundaries: U.S. Census Bureau cartographic boundary files.

Rankings

Definition

Highest daily Air Quality Index (AQI) value recorded in a US county during the year, from the EPA AirData annual summaries. Values above 500 are beyond the AQI scale and are published as EPA computes them.

A single day decides the value, so one wildfire or dust event can set it. Dust from the dry Owens Lake bed puts Inyo and Mono counties in California in the thousands. 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.

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How to cite

U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest daily AQI. 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: highest daily AQI (Highest daily Air Quality Index (US EPA), Calvert County, 1996 to 2025) [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: highest daily AQI, Highest daily Air Quality Index (US EPA), Calvert County, 1996 to 2025. U.S. Environmental Protection Agency, 13 July 2026, https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Invokely, https://invokely.ai/en/highest-daily-air-quality-index/calvert-county-maryland. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Environmental Protection Agency. 2026. EPA AirData annual AQI by county: highest daily AQI. Highest daily Air Quality Index (US EPA), Calvert County, 1996 to 2025. Dataset. Accessed October 12, 2026. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Also distributed by Invokely, https://invokely.ai/en/highest-daily-air-quality-index/calvert-county-maryland.

Harvard

U.S. Environmental Protection Agency (2026) EPA AirData annual AQI by county: highest daily AQI, Highest daily Air Quality Index (US EPA), Calvert County, 1996 to 2025 [Dataset]. Available at: https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual, via Invokely: https://invokely.ai/en/highest-daily-air-quality-index/calvert-county-maryland (Accessed: 12 October 2026).

BibTeX
@misc{environmental_highest_daily_air_quality_2025,
  author = {{U.S. Environmental Protection Agency}},
  title = {{EPA AirData annual AQI by county: highest daily AQI: Highest daily Air Quality Index (US EPA), Calvert County, 1996 to 2025}},
  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/en/highest-daily-air-quality-index/calvert-county-maryland. Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest daily AQI. 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: highest daily AQI: Highest daily Air Quality Index (US EPA), Calvert County, 1996 to 2025
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/en/highest-daily-air-quality-index/calvert-county-maryland
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/en/highest-daily-air-quality-index/calvert-county-maryland.
N1  - Publisher attribution: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: highest daily AQI. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
ER  - 
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Questions

What is the highest daily Air Quality Index (US EPA) in Calvert County?

Highest daily Air Quality Index (US EPA) in Calvert County was 77 in 2025, according to the U.S. Environmental Protection Agency. That is down 31 from 2024. That is the 16th highest of 16 counties in 2025.

Where does this figure come from?

U.S. Environmental Protection Agency. EPA AirData annual AQI by county: highest daily AQI. Retrieved by Invokely on 2026-10-12.

What was the highest highest daily Air Quality Index (US EPA) in Calvert County?

206 in 2012, the highest value since 1996 in this series.

Related statistics for Calvert County

All statistics for Calvert County | Calvert County in figures