EnviroNearby

Carolina, Puerto Rico air quality history

Daily Air Quality Index summaries from EPA monitors in Carolina, Puerto Rico, 1990–2005.

100%
Good days in 2005
19
Median daily AQI, 2005
0
Days above 100 in 2005
12
Days with an AQI in 2005 (of 365)

In 2005, EPA reported a daily Air Quality Index (AQI) for Carolina, Puerto Rico on 12 days. 12 of those days (100%) were in the Good range, and the median daily AQI was 19. That median is lower than the typical monitored county in Puerto Rico (median 31.5 across 4 counties), and lower than the typical monitored U.S. county (44). The main pollutant was coarse particles (PM10) on 12 days.

EPA did not report an AQI for every day of 2005 here (12 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 2005; EPA's files for 2006–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (2000, 2001, 2002, 2003, 2004, 2005…) 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%1990: Good 44 of 49 days1990: Moderate 5 of 49 days19901991: Good 55 of 57 days1991: Moderate 2 of 57 days1992: Good 53 of 57 days1992: Moderate 4 of 57 days19921993: Good 54 of 57 days1993: Moderate 3 of 57 days1994: Good 55 of 57 days1994: Moderate 2 of 57 days19941995: Good 44 of 44 days1996: Good 51 of 52 days1996: Moderate 1 of 52 days19961997: Good 47 of 50 days1997: Moderate 3 of 50 days1998: Good 49 of 51 days1998: Moderate 2 of 51 days19981999: Good 37 of 38 days1999: Moderate 1 of 38 days2000: Good 48 of 52 days2000: Moderate 4 of 52 days20002001: Good 57 of 58 days2001: Moderate 1 of 58 days2002: Good 53 of 55 days2002: Moderate 2 of 55 days20022003: Good 51 of 55 days2003: Moderate 4 of 55 days2004: Good 49 of 53 days2004: Moderate 4 of 53 days20042005: Good 12 of 12 days2005
  • 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 year0501001990: 90th percentile AQI 511991: 90th percentile AQI 361992: 90th percentile AQI 431993: 90th percentile AQI 441994: 90th percentile AQI 421995: 90th percentile AQI 291996: 90th percentile AQI 311997: 90th percentile AQI 411998: 90th percentile AQI 441999: 90th percentile AQI 402000: 90th percentile AQI 372001: 90th percentile AQI 402002: 90th percentile AQI 322003: 90th percentile AQI 412004: 90th percentile AQI 312005: 90th percentile AQI 421990: Median AQI 201991: Median AQI 191992: Median AQI 191993: Median AQI 201994: Median AQI 231995: Median AQI 191996: Median AQI 191997: Median AQI 211998: Median AQI 201999: Median AQI 212000: Median AQI 192001: Median AQI 192002: Median AQI 202003: Median AQI 192004: Median AQI 172005: Median AQI 19199019921994199619982000200220042005
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2005

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)12100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2005121200000194250PM10
2004534940000173161PM10
2003555140000194159PM10
2002555320000203255PM10
2001585710000194053PM10
2000524840000193770PM10
1999383710000214052PM10
1998514920000204478PM10
1997504730000214181PM10
1996525110000193194PM10
1995444400000192949PM10
1994575520000234262PM10
1993575430000204458PM10
1992575340000194367PM10
1991575520000193680PM10
1990494450000205157PM10

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 Puerto Rico

Source: U.S. EPA AirData, “Annual AQI by County” files for 1990–2005 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem