What Is the Air Quality in Guaynabo, Puerto Rico?

Guaynabo, Puerto Rico earns a C — air quality is fair, but not great. With a 5-year median AQI of 29, the city sees a meaningful number of "Moderate" days each year, when the EPA flags air as a concern for unusually sensitive people.

Guaynabo, Puerto Rico's 5-year median AQI of 29 is 12 points below the national average of 41 — meaningfully cleaner than the typical U.S. metro tracked here. Within Puerto Rico, Guaynabo, 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).

Air quality in Guaynabo, Puerto Rico has been getting worse over the past decade, with median AQI climbing by roughly 1.4 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, Guaynabo, Puerto Rico posted a median AQI of 25. By 2023 that figure was 32 — a rise of 7 AQI points dirtier across 10 years of EPA records.

Across the past five years, this area has logged just 4 days where AQI rose into the "Unhealthy for Sensitive Groups" range or worse — about 1 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. NO2 concentrations drop quickly as you move away from traffic. Walking or biking on residential streets rather than along major arterials can cut personal exposure in half.