Air Quality Forecast

DNREC provides regular air quality forecasts and an air quality index to help you know if you need to take precautions. To sign up for air quality email alerts, simply send us a blank email and we’ll add you to the list.

The Forecast

Date: Sunday, September 19, 2021

Ozone Action Day? No

Forecast Discussion:
Saturday, September 18: Decreasing clouds and temperatures in the low-80s will promote ozone formation. However, light northwesterly to westerly winds will aid dispersion and transport a clean air mass into the First State. These conditions will result in high-Good AQI levels. Sunday, despite a ridge of high pressure aloft reducing atmospheric mixing, northwesterly winds will continue to transport clean air into the region, leading to another day of high-Good AQI levels. Monday, mostly sunny skies will support ozone formation in Delaware. However, light to moderate easterly winds will keep pollutants well dispersed, yielding continued high-Good AQI levels.

Updated: 09/17/2021

September 19, 2021
Ozone: 49

September 20, 2021
Ozone: 48

The Air Quality Partnership of Delaware

DNREC is a member of the Air Quality Partnership of Delaware, which is a public/private coalition of businesses, agencies, and individuals interested in clean air. The mission of this partnership is to raise awareness and inform Delawareans about practices that improve air quality and citizen health.

You Can Help Keep Our Air Clean

Ride DART First State. Don’t know what bus route to ride, or what time to be at the bus stop? Visit DART’s website or call 1-800-652-DART in New Castle and Kent Counties, and 1-800-553-DART in Sussex County.

Carpool with friends and/or coworkers. To find a carpool partner or if you already ride the bus/train, and want to register for our Home Free Guarantee, call RideShare Delaware at 1-888-RIDE-MATCH or visit

Limit daytime driving and combine errands.

When you must drive, try to avoid congested periods.

Maintain your vehicle’s emission control equipment.

Walk or ride a bicycle for short, easy trips.

Postpone the use of gasoline-powered mowers until evening.

Refuel your car in the evening – and don’t top off your tank.

Avoid lighting your barbecue with starter fluid.

Avoid prolonged idling and jackrabbit starts.

Use latex rather than oil-based paints.

Ground-level ozone is a real threat to our health because it reacts with sensitive lung tissue, causing harmful changes in breathing passages. Children, the elderly and individuals with respiratory diseases are especially harmed by ozone. Even healthy individuals can be harmed if they attempt strenuous activity on days with high ozone…those days should be used for inside low physical stress activity.

Remember, this may seem like a small contribution by you as an individual, but if we can get solid public involvement, working together we CAN make a real difference!

Any health related questions should be directed to the Division of Public Health at 302-744-4700. All other questions should be directed to the Division of Air Quality at 302-739-9402.

Also, if you’re interested in seeing hourly monitoring data of ozone and other air pollutants visit the Delaware Air Quality Monitoring Network website.