Air Quality Forecast

DNREC works with the EPA and regional partners to track air quality and help you know if you need to take precautions. For current ozone and particulate conditions, visit the EPA AirNow website.

Ozone forecasting season has ended. Daily air quality forecasts will resume in May. To sign up for air quality email alerts, send a blank email to be added to the list.

Air Quality Guides for Ozone and Particulate Matter

The following are links to guides from the EPA, in English and Spanish, to help readers reduce their exposure and protect their health when the air quality is bad.

Guide for ozone

Guia de la calidad del aire sobre el ozono

Guide for particulate matter

Guia de la calidad del aire sobre la contaminacion por particulas

The Air Quality Index

The Air Quality Index, known as the AQI, is an index for reporting daily air quality. It tells you how clean or polluted your air is, and what associated health effects might be a concern for you. The AQI focuses on health effects you may experience within a few hours or days after breathing polluted air.

The EPA calculates the AQI for the five major air pollutants for which it has established national air quality standards to protect public health. Ground-level ozone and airborne particles are the two pollutants that pose the greatest threat to human health in this country.

You can access air monitoring station data in Delaware via DNREC. Visit the EPA Air Now site to learn more about the AQI, to see forecasts for other locations, and to see live data for Delaware or for the nation as a whole.

AQI Levels of Concern, Color Code, and Values

The AQI presents a numerical value, ranging from zero to 301 or higher, that corresponds to the level of concern for human health. Those levels of concern are represented by a color code ranging from green, a low level of concern, up to maroon, a very high level of concern. Most days in Delaware are in the green or yellow range, though there are occasional days when the AQI reaches levels that are unhealthy for some groups.

Color Level of Concern Value Description of Air Quality
Green Good 0 to 50 Air quality is satisfactory, and air pollution poses little or no risk.
Yellow Moderate 51 to 100 Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.
Orange Unhealthy for Sensitive Groups 101 to 150 Members of sensitive groups may experience health effects. The general public is less likely to be affected.
Red Unhealthy 151 to 200 Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects.
Purple Very Unhealthy 201 to 300 Health alert: The risk of health effects is increased for everyone.
Maroon Hazardous 301 and higher Health warning of emergency conditions: everyone is more likely to be affected.

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.

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.