Delaware City, Delaware Air Quality
Delaware City has a median AQI of 46, earning an air quality grade of B+ — good air quality that ranks better than 24% of US cities. Air quality has been improving steadily over the past decade, a positive sign for residents. Ground-level ozone is the primary concern, typically peaking on warm sunny days due to vehicle and industrial emissions. In 2025, Delaware City recorded 110 good air quality days (60% of monitored days) and 4 unhealthy days.
Population: 1,950 • County: New Castle
Current AQI
Quick Facts
| Current AQI | 13 — Good |
| Air Quality Grade | B+ |
| Median AQI (2025) | 46 |
| vs. U.S. Cities | Better than 24% |
| Primary Pollutant | Ozone |
| Unhealthy Days/Year | 4 |
| 10-Year Trend | ↑ Improving |
| Data Source | EPA AQS (historical) · AirNow (live) |
Health Recommendation
Air quality is satisfactory, and air pollution poses little or no risk.
It's a great day to be active outside!
5-Day AQI Forecast
Last 90 Days
Current Pollutant Levels
Real-time data from EPA AirNow
Local Air Quality Context
Air quality data for Delaware City is sourced from the Rte 9 Del. City monitoring area, located approximately 1 miles from city center. This EPA-certified station continuously tracks ground-level ozone, the primary driver of air quality alerts in this area.
Delaware City has relatively consistent air quality throughout the year without a strong seasonal peak. Air quality is primarily influenced by local traffic, industrial activity, and regional weather patterns rather than a single seasonal driver.
AQI Trend (10 Years)
Air Quality Days by Year
Delaware City Median AQI by Year
Annual EPA air quality data for Delaware City — median AQI, day-category breakdown, and primary pollutant per year.
| Year | Median AQI | Good Days | Unhealthy Days | Max AQI | Primary Pollutant |
|---|---|---|---|---|---|
| 2025 | 46 | 110 | 4 | 161 | Ozone |
| 2024 | 43 | 246 | 4 | 119 | Ozone |
| 2023 | 51 | 173 | 8 | 282 | PM2.5 |
| 2022 | 48 | 208 | — | 93 | PM2.5 |
| 2021 | 48 | 195 | 4 | 144 | PM2.5 |
| 2020 | 46 | 231 | 2 | 105 | PM2.5 |
| 2019 | 47 | 207 | 3 | 136 | PM2.5 |
| 2018 | 48 | 212 | 6 | 150 | PM2.5 |
| 2017 | 50 | 187 | 10 | 147 | PM2.5 |
| 2016 | 52 | 173 | 10 | 154 | PM2.5 |
Source: EPA Air Quality System (AQS) annual summaries. "Unhealthy Days" includes Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, and Hazardous categories.
2025 Air Quality Summary
Primary Pollutant Days (2025)
Days when each pollutant was the primary driver of AQI. Learn about pollutants →
Frequently Asked Questions About Delaware City Air Quality
What is the air quality in Delaware City today?
The current AQI in Delaware City is 13, rated "Good". Air quality is good — outdoor activity is safe for everyone today. Air quality is satisfactory, and air pollution poses little or no risk.
Is air quality in Delaware City getting better or worse?
Air quality in Delaware City has been improving. The median AQI has dropped 6 points (from 52 in 2016 to 46 in 2025), a positive trend for residents.
What is the most common air pollutant in Delaware City?
Ozone is the primary air pollutant in Delaware City, responsible for 106 days (58% of monitored days) in 2025. Ground-level ozone forms when sunlight reacts with emissions from vehicles and industry, typically peaking on hot summer afternoons.
How many unhealthy air days does Delaware City have per year?
In 2025, Delaware City recorded 60% good air quality days (110 days) out of 182 monitored days. There were 3 Unhealthy for Sensitive Groups days and 1 Unhealthy days (AQI above 100). The highest single-day AQI recorded was 161.
What air quality grade does Delaware City receive?
Delaware City receives an air quality grade of B+, placing it better than 24% of US cities. This is based on a median AQI of 46 in 2025, with 110 good air quality days. The EPA monitors air quality in this area continuously using certified monitoring stations.
Air Quality Grade
Better than 24% of US cities
Nearby Cities
Get AQI Alerts
Receive notifications when air quality changes in Delaware City
National Rankings
See how Delaware City compares to every other US city by air quality.
Best Air Quality Cities →All city rankingsRecommended Air Purifiers for Delaware City
Ozone is Delaware City's primary pollutant. Standard HEPA filters don't capture ozone molecules — you need activated carbon or PECO technology to chemically break them down. We highlight those units here.
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