Air quality in Bethesda, Maryland, United States of America today

Mr. Duck’s Air Quality Score

Moderate air today for Bethesda, Maryland, United States of America

⚠️ This website is currently under active development. Some data may be incomplete or temporarily inaccurate. For health-critical decisions, please verify information through official government or environmental sources.

Categories follow US EPA AQI breakpoints for PM (estimate from latest valid measurements; this project does not compute EPA NowCast/24-hour AQI yet).

This friendly indicator summarizes the latest city readings. For health guidance, please see: EPA AirNow or WHO.

Air quality today

The air quality in Bethesda, Maryland is currently classified as Moderate. The primary pollutant identified is PM2.5 (fine particles). Measurements show a PM2.5 concentration of 23.13 µg/m³ based on eleven valid observations recorded by OpenAQ.

Data for this assessment were gathered from multiple monitoring sites and reflect the latest available values. This page is informational; for health guidance, use official sources such as EPA AirNow or WHO.

Latest sensor values

PM categories follow US EPA AQI breakpoints, shown here as an estimate derived from the latest valid measurements (this project does not compute EPA NowCast/24-hour AQI yet).

What the data includes

The Bethesda air‑quality dataset pulls from three monitoring sites and contains thirteen individual measurement rows. Six pollutants are currently reported: ozone (O₃), fine particulate matter (PM₂.5), coarse particles (PM₁₀), ultrafine particles (PM₁), relative humidity, temperature, and particle count (UM003). The most recent data were recorded on 2026‑02‑11 at 01:00 UTC for PM₂.5, PM₁, relative humidity, temperature and UM003, all from the Wildwood station. Ozone’s newest entry is older, dated 2025‑11‑10 at 15:00 UTC from Rockville, while the single PM₁₀ reading comes from 2025‑01‑13 at 23:00 UTC in North Bethesda.

Across the fresh February measurements, PM₂.5 values range from 10.0 to 24.34 µg/m³ with a median of about 23.13 µg/m³, indicating that most recent samples sit near the upper end of that span. PM₁ shows a tighter spread, from roughly 10.13 to 16.77 µg/m³ and a median of 13.45 µg/m³. Relative humidity in the latest hour varied between 27.60 % and 30.58 %, with a median close to 29.09 %; temperature hovered narrowly from 10.61 °C to 11.01 °C, median 10.81 °C. Particle counts (UM003) were most variable, ranging from 746 to 2,706 particles/cm³ and a median of about 1,726.

Because ozone and PM₁₀ are only represented by single, older records, the dataset provides limited insight into current conditions for those pollutants, while the other five parameters benefit from multiple recent observations. The overall picture shows that Bethesda’s air‑quality reporting is freshest for particulate matter, humidity, temperature and particle concentration, but gaps remain for ozone and coarse dust, so conditions can differ across locations and times within the city.

Learn more about sources and filtering: About the data.

Trusted references: WHO (Air pollution) · US EPA AirNow · European Environment Agency (Air)

Latest sensor values (bars)

PM categories follow US EPA AQI breakpoints, shown here as an estimate derived from the latest valid measurements (this project does not compute EPA NowCast/24-hour AQI yet).

Data notes

The data shown for Bethesda, Maryland reflects 11 valid measurements and was updated today (2026‑02‑11T01:00:00+00:00). These readings represent a snapshot of conditions at the time of collection; air quality can vary by location and time within the city, so values may differ across neighborhoods or later in the day.

OpenAQ station rows