Puerto Rico · County air quality · 2025
Guaynabo County, Puerto Rico
Median AQI 33 (Good). 81.6% of monitored days rated Good, direct from EPA Air Quality System stations.
- 33
- Median AQI
- 81.6%
- Good-air days
- 0
- Unhealthy days
- 60%
- Cleaner than US counties
Guaynabo County's 2025 annual median AQI is 33 (Good), with 81.6% Good days
According to the U.S. EPA Air Quality System, Guaynabo County, Puerto Rico posted a 2025 median AQI of 33 (Good) across 114 monitored days, with 81.6% rated Good and 0 unhealthy or worse. This is an annual comparison, not today's advisory.
Data source EPA Air Quality System (AQS)
- Cleaner than US
- Guaynabo County's 81.6% Good-day share places it cleaner than 60% of US counties in 2025.
- Closest median-AQI peer
- Apache County (86.2% Good, median AQI 33) is the closest nationwide median-AQI peer to Guaynabo County.
- 2021–2025 trend
- Guaynabo County's floor-qualifying Good-day share is improving from 2021 to 2025 (72.3% → 81.6%).
- Median AQI
- Median AQI: 33
According to the 2025 EPA AQS county release on PlainAirData, Guaynabo County, Puerto Rico ranks #123 of 951 by median AQI (33) and #377 by good-day share (81.6%). Ponce County, Puerto Rico is #1 of 951 by median AQI (3, 91.4% Good days) at good-day-share #159 ≠ largest of 7 at 100.0% Good days #1 by good-day share (100.0%, median AQI 9) at median-AQI #7.
Annual release change
What changed in the 2025 EPA annual release
- Guaynabo County's Good-day share rose from 79.1% to 81.6% between the 2024 and 2025 EPA annual releases, a change of +2.4 percentage points.
- Guaynabo County's peak single-day AQI fell from 81 to 67 between the 2024 and 2025 EPA annual releases, a change of -14 points.
Data updated August 2026
- Good · 93 d · 81.6%
- Moderate · 21 d · 18.4%
How did Guaynabo County's air break down in 2025?
Across 114 monitored days, 93 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 67 (Moderate).
EPA AQS →Share of monitored days at AQI 0-50 (Good band).
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
Where Guaynabo County sits nationally
COUNT-derived placement among 951 US counties with at least 100 monitored days in 2025. Guaynabo County's Good-day share is 81.6% - cleaner than 60% of that comparison set.
Guaynabo County Good-day share vs. every US county
Share of monitored days in the Good band (AQI 0–50) - EPA AQS annual release
81.6% Cleaner than 60% higher than 60% of 951 US counties
Each bar is a band; taller bars hold more US counties. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source U.S. Environmental Protection Agency, Air Quality System (AQS) · 2025
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Guaynabo County.
- PM2.5 · 109 days · 95.6%
- PM10 · 5 days · 4.4%
2024 daily-monitor rhythm in Guaynabo County
Month-by-month median AQI from EPA day-level county monitors (115 reported days in 2024). Jul posted the highest typical readings (median AQI 51, peak 81); Nov was cleanest at median 27. Summer months (Jun–Aug) averaged median AQI 43 vs 33 in Dec–Feb.
Five-year seasonal record
EPA day-level county files · 2020–2024518 daily readings show a recurring local pattern: Jul has the highest matched-month median AQI (51), while Jan is lowest (27). Each cell is that month’s median daily AQI, not a current-air forecast.
Lower AQI is better. The colors summarize EPA AQI bands; gaps mean the county had no day-level record for that month.
Health Impact Assessment
Guaynabo County's air quality is rated Good based on 81.6% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 81.6% of monitored days in 2025, with a median AQI of 33. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is PM2.5, driving AQI on 109 of 114 monitored days.
5-Year Air Quality Trend
Air quality is improving in Guaynabo County. Highest Good-day share: 2025 (81.6%, 93 of 114 monitored days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 68 | 15 | 0 | 0 | 29 | 75 |
| 2021 | 86 | 33 | 0 | 0 | 33 | 77 |
| 2022 | 81 | 13 | 0 | 0 | 29 | 80 |
| 2023 | 82 | 25 | 0 | 0 | 32 | 74 |
| 2024 | 91 | 24 | 0 | 0 | 31 | 81 |
| 2025 | 93 | 21 | 0 | 0 | 33 | 67 |
How does Guaynabo County compare?
How Guaynabo County compares
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer. Spotted a figure that looks wrong? Report a correction.
Source: U.S. EPA Air Quality System (AQS) Annual AQI by county summary files for Guaynabo County, Puerto Rico · 2020–2025
Download this county's annual AQI row as CSV , with the same EPA fields and denominator shown on this page.
Every figure on PlainAirData is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.