Mayagnez, Puerto Rico Air Quality Today
AirHistory tracks long-run EPA monitoring rather than live readings, so for the live number check AirNow.gov below. As a baseline, Mayagnez, Puerto Rico's most recent EPA year (2023) posted a median AQI of 25 (Good) against a 5-year median of 31 and an overall Grade of C. The dominant pollutant is Fine Particulate Matter (PM2.5), which tells you which days are most likely to spike.
Check Today's Live AQI in Mayagnez, Puerto Rico
AirHistory is built on 10 years of EPA Air Quality System records, so it shows you what air quality in Mayagnez, Puerto Rico typically looks like — not the live reading for this exact hour. For today's real-time AQI, check AirNow.gov (the EPA's official live index) or the AirNow Fire and Smoke Map during wildfire season.
That said, the history is the best predictor of a normal day. In 2023, Mayagnez, Puerto Rico posted a median AQI of 25 (Good), with 254 "Good" days and 0 days that crossed into "Unhealthy for Sensitive Groups" or worse. The dominant pollutant, Fine Particulate Matter (PM2.5), is the one most likely to push today's number up — Fine particulate matter — particles less than 2.5 micrometers across — comes mostly from combustion: vehicle exhaust, wildfire smoke, residential wood burning, and industrial emissions. Because these particles are small enough to enter the bloodstream, PM2.5 is the pollutant most strongly linked to cardiovascular disease, respiratory illness, and premature death.
Mayagnez, Puerto Rico Air Quality Snapshot
| Air Quality Grade | C61/100 |
| 5-Year Median AQI | 31 (Good) |
| Most Recent Median AQI (2023) | 25 (Good) |
| Dominant Pollutant | Fine Particulate Matter (PM2.5) |
| 10-Year Trend | Worsening (+0.94 AQI/yr) |
| Unhealthy Days (last 5 yr) | 11 |
| National Rank (cleanest = #1) | #142 of 1,020 (14th cleanest percentile) |
| Puerto Rico Rank | #10 of 11 |
What Does the C Grade Mean?
Mayagnez, Puerto Rico earns a C — air quality is fair, but not great. With a 5-year median AQI of 31, the city sees a meaningful number of "Moderate" days each year, when the EPA flags air as a concern for unusually sensitive people.
Mayagnez, Puerto Rico's 5-year median AQI of 31 is 10 points below the national average of 41 — meaningfully cleaner than the typical U.S. metro tracked here. Within Puerto Rico, Mayagnez, Puerto Rico runs more polluted than the state average of 23 — local sources or geography are concentrating pollution above the state's typical reading.
For context within Puerto Rico: Caguas, Puerto Rico currently holds the state's cleanest grade (A, AQI 10), while Catano, Puerto Rico sits at the bottom (D, AQI 42).
What's in Mayagnez, Puerto Rico's Air?
The dominant pollutant in Mayagnez, Puerto Rico is Fine Particulate Matter (PM2.5). Fine particulate matter — particles less than 2.5 micrometers across — comes mostly from combustion: vehicle exhaust, wildfire smoke, residential wood burning, and industrial emissions. Because these particles are small enough to enter the bloodstream, PM2.5 is the pollutant most strongly linked to cardiovascular disease, respiratory illness, and premature death.
Days by Dominant Pollutant (2023)
| Pollutant | Days as Dominant | Share of Year |
|---|---|---|
| Fine Particulate Matter (PM2.5) | 208 | 73% |
| Ground-Level Ozone | 77 | 27% |
Is the Air Getting Better or Worse?
Air quality in Mayagnez, Puerto Rico has been getting worse over the past decade, with median AQI climbing by roughly 0.9 points per year. That bucks the national trend of broad improvement, and most often reflects either growing wildfire smoke exposure (particularly across the West) or rising local emissions from population and freight growth.
In 2014, Mayagnez, Puerto Rico posted a median AQI of 23. By 2023 that figure was 25 — a rise of 2 AQI points dirtier across 6 years of EPA records.
Year-by-Year AQI in Mayagnez, Puerto Rico
| Year | Median AQI | Good Days | Unhealthy Days | Dominant Pollutant |
|---|---|---|---|---|
| 2014 | 23 | 8 | 0 | PM2.5 |
| 2019 | 33 | 136 | 0 | PM2.5 |
| 2020 | 22 | 266 | 4 | PM2.5 |
| 2021 | 38 | 231 | 2 | PM2.5 |
| 2022 | 38 | 235 | 5 | PM2.5 |
| 2023 | 25 | 254 | 0 | PM2.5 |
Health Context for Mayagnez, Puerto Rico
Across the past five years, this area has logged just 11 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 2 days per year, or roughly one every other month. That is a low count by national standards.
Healthy adults can continue normal outdoor activity in most weather, but should pay attention to AQI alerts during the worst pollution windows. People with asthma, heart disease, or pregnancy should reduce prolonged or intense outdoor exertion on flagged days, and consider running an indoor HEPA air cleaner during peak season. Because PM2.5 penetrates deep into the lungs and bloodstream, an N95 or KN95 mask provides meaningful protection on smoky or high-particulate days — surgical masks do not.
How This Grade Is Calculated
The AirHistory Air Quality Grade combines four signals: the 5-year median AQI (40% of the score), the 10-year trend direction (30%), the count of unhealthy days per year (20%), and the dominant pollutant type (10%). All four come directly from the EPA Air Quality System (AQS), which aggregates readings from federally certified monitors. Read the full methodology.
More about Mayagnez, Puerto Rico
Mayagnez, Puerto Rico has an Air Quality Grade of C (fair) with a 5-year median AQI of 31. The dominant pollutant is Fine Particulate Matter (PM2.5), and air quality has been worsening over the past decade.
This answer pulls from the EPA Air Quality System (AQS), the authoritative federal source for U.S. air quality and pollution monitoring. The headline number above is the direct answer; what follows is the additional context most readers need to use the answer for a real decision rather than just a fact lookup.
For readers turning this answer into action: cross-reference against the underlying the EPA Air Quality System (AQS) record before acting on time-sensitive decisions. The site renders the data as it was published; subsequent revisions can shift the picture, and the live federal data is always the authoritative current reference.
Source: EPA Outdoor Air Quality Data, 2026.