Air quality in Chester, PA today

Air quality in Chester, PA right now

Right now the modelled US Air Quality Index for Chester, Pennsylvania, United States is 131, which falls in the "Unhealthy for Sensitive Groups" band (up to 150). People with heart or lung disease, older adults, children and teens should cut back on prolonged or heavy exertion outdoors.

The index is driven mainly by PM2.5, whose own sub-index is 131. Fine and coarse particles come from traffic, heating, industry, dust and smoke; they build up on calm nights and clear when wind or rain arrives.

PM2.5 is 17 µg/m³, 1.1 times the WHO 24-hour guideline of 15 µg/m³; PM10 is 19 µg/m³ against a guideline of 45; ozone is 102 µg/m³ (above the WHO 8-hour level of 100); nitrogen dioxide is 7.7 µg/m³ (below the 24-hour guideline of 25).

Also this hour: UV index 0.9, carbon monoxide 155 µg/m³.

Chester, PA AQI forecast: next 48 hours

Over the next 24 hours the AQI is forecast to range from 95 around Mon 12:00 pm to 133 around Sun 8:00 pm, from "Moderate" at best to "Unhealthy for Sensitive Groups" at worst.

The following day is expected to be cleaner, averaging about 76 against 114 for the next 24 hours.

Every third hour of the CAMS forecast via Open-Meteo. US AQI uses rolling averages (24 h for particles, 8 h for ozone), so it moves more slowly than the hourly concentrations.

Best time to be outside in Chester, PA today

Between 6 am and 9 pm local time, the cleanest air today is forecast around 4:00 pm (AQI 131, Unhealthy for Sensitive Groups) and the worst around 8:00 pm (AQI 133). The difference across the day is small, so timing matters little.

Chester, PA vs the rest of United States

Across 619 United States cities we track, the average US AQI right now is 49 (Good). Chester, PA at 131 is 82 points worse than average.

For context, the median across 3,556 cities worldwide is 58.

Air quality in cities near Chester, PA

Model vs measured

We found no measured PM2.5 sensor cell within 25 km of Chester, PA, so the numbers on this page are model estimates. Models capture regional pollution well but can miss very local sources such as a busy road or a nearby fire.

Wildfire smoke

PM2.5 is forecast to reach 63 µg/m³ in the next 24 hours while NASA satellites detected 42 fire hotspots within 300 km in the last day (nearest about 17 km away). Smoke is a likely contributor: keep windows closed, run an air purifier or HVAC filter, and check the fire map before heading out.

• Wildfires near Chester, PA
• Live wildfire map

Advice for sensitive groups

At 131, children, older adults, pregnant people and anyone with asthma, COPD or heart disease should limit time outdoors, especially strenuous activity. A well-fitted N95/FFP2 mask cuts particle exposure; it does not filter ozone.

What the US AQI numbers mean

Values on this page are modelled by CAMS (Copernicus) and served by Open-Meteo; they are estimates for the area around the city centre, not readings from an official monitor.

Nearby cities

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• Air quality in Newark, DE
• Air quality in Jackson, NJ
• Air quality in Vineland

More for Chester

• Weather warnings for Chester
• Wildfires near Chester
• Earthquakes near you
• Aurora forecast
• Planes overhead
• Live cameras
• Live wildfire map

Air quality elsewhere

• Air quality in Pennsylvania
• Air quality in United States
• Air quality worldwide