EnviroNearby

St Croix, Virgin Islands air quality history

Daily Air Quality Index summaries from EPA monitors in St Croix, Virgin Islands, 1996–2022.

88%
Good days in 2009
16
Median daily AQI, 2009
0
Days above 100 in 2009
243
Days with an AQI in 2009 (of 365)

In 2009, EPA reported a daily Air Quality Index (AQI) for St Croix, Virgin Islands on 243 days. 213 of those days (88%) were in the Good range, and the median daily AQI was 16. That median is lower than the typical monitored U.S. county (41). The main pollutant was coarse particles (PM10) on 220 days.

EPA did not report an AQI for every day of 2009 here (243 of 365 days). Figures describe monitored days only; seasonal monitoring (for example, ozone measured only in warmer months) can make a county look cleaner or dirtier than a full-year record would.

The most recent year with data for this county is 2022; EPA's files for 2023–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (2017, 2018, 2019, 2020, 2021, 2022…) 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.

Share of monitored days in each AQI category, by year0%25%50%75%100%1996: Good 6 of 7 days1996: Unhealthy for Sensitive Groups 1 of 7 days19961997: Good 36 of 37 days1997: Moderate 1 of 37 days1998: Good 36 of 39 days1998: Moderate 3 of 39 days19981999: Good 31 of 43 days1999: Moderate 12 of 43 days2000: Good 43 of 51 days2000: Moderate 8 of 51 days20002001: Good 47 of 54 days2001: Moderate 7 of 54 days2002: Good 42 of 58 days2002: Moderate 16 of 58 days20022003: Good 54 of 69 days2003: Moderate 15 of 69 days2004: Good 67 of 82 days2004: Moderate 15 of 82 days20042005: Good 43 of 55 days2005: Moderate 12 of 55 days2006: Good 27 of 48 days2006: Moderate 19 of 48 days2006: Unhealthy for Sensitive Groups 2 of 48 days20062007: Good 39 of 57 days2007: Moderate 18 of 57 days2008: Good 111 of 132 days2008: Moderate 21 of 132 days20082009: Good 213 of 243 days2009: Moderate 30 of 243 days2010: Good 25 of 58 days2010: Moderate 33 of 58 days20102011: Good 30 of 33 days2011: Moderate 3 of 33 days2012: Good 27 of 36 days2012: Moderate 9 of 36 days20122013: Good 22 of 25 days2013: Moderate 3 of 25 days2014: Good 23 of 47 days2014: Moderate 24 of 47 days20142015: Good 16 of 38 days2015: Moderate 22 of 38 days2016: Good 7 of 13 days2016: Moderate 6 of 13 days20162017: Good 21 of 26 days2017: Moderate 5 of 26 days2018: Good 16 of 22 days2018: Moderate 6 of 22 days20182019: Good 47 of 57 days2019: Moderate 10 of 57 days2020: Good 50 of 59 days2020: Moderate 9 of 59 days20202021: Good 46 of 55 days2021: Moderate 9 of 55 days2022: Good 22 of 26 days2022: Moderate 4 of 26 days2022
  • 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 and 90th-percentile daily AQI, by year0501001501996: 90th percentile AQI 1061997: 90th percentile AQI 271998: 90th percentile AQI 491999: 90th percentile AQI 632000: 90th percentile AQI 532001: 90th percentile AQI 522002: 90th percentile AQI 562003: 90th percentile AQI 612004: 90th percentile AQI 562005: 90th percentile AQI 642006: 90th percentile AQI 722007: 90th percentile AQI 712008: 90th percentile AQI 562009: 90th percentile AQI 532010: 90th percentile AQI 672011: 90th percentile AQI 462012: 90th percentile AQI 562013: 90th percentile AQI 622014: 90th percentile AQI 682015: 90th percentile AQI 802016: 90th percentile AQI 622017: 90th percentile AQI 612018: 90th percentile AQI 602019: 90th percentile AQI 632020: 90th percentile AQI 582021: 90th percentile AQI 522022: 90th percentile AQI 611996: Median AQI 31997: Median AQI 111998: Median AQI 171999: Median AQI 312000: Median AQI 352001: Median AQI 272002: Median AQI 322003: Median AQI 302004: Median AQI 242005: Median AQI 262006: Median AQI 432007: Median AQI 372008: Median AQI 172009: Median AQI 162010: Median AQI 532011: Median AQI 292012: Median AQI 192013: Median AQI 232014: Median AQI 522015: Median AQI 542016: Median AQI 442017: Median AQI 262018: Median AQI 292019: Median AQI 272020: Median AQI 252021: Median AQI 282022: Median AQI 2919961998200020022004200620082010201220142016201820202022
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2009

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.

PollutantDays as main pollutantShare of monitored days
Coarse particles (PM10)22091%
Fine particles (PM2.5)239%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2022262240000296167PM2.5
2021554690000285276PM2.5
2020595090000255884PM2.5
20195747100000276374PM2.5
2018221660000296077PM2.5
2017262150000266170PM2.5
201613760000446267PM2.5
20153816220000548088PM2.5
20144723240000526893PM10
2013252230000236272PM10
2012362790000195659PM2.5
2011333030000294665PM2.5
20105825330000536784PM10
2009243213300000165397PM10
2008132111210000175697PM10
20075739180000377185PM10
200648271920004372116PM2.5
20055543120000266490PM2.5
20048267150000245670PM2.5
20036954150000306173PM2.5
20025842160000325667PM10
2001544770000275260PM10
2000514380000355374PM2.5
19994331120000316382PM2.5
1998393630000174980PM10
1997373610000112757PM10
199676010003106106PM10

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.

All monitored counties in Virgin Islands

Source: U.S. EPA AirData, “Annual AQI by County” files for 1996–2022 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem