CALIFORNIA, Md. — Maryland residents may see air quality alerts at different times of the year, especially during hot summer weather or when wildfire smoke travels into the region from other states or Canada. These alerts can raise questions about whether it is safe to exercise outdoors, send children to the playground or spend the day on the Chesapeake Bay.
Understanding Maryland air quality alerts can help families make informed decisions without unnecessary worry. While many days have good air quality, changing weather patterns, traffic emissions and smoke can temporarily affect the air people breathe across Southern Maryland, Anne Arundel County, Baltimore, Washington and other parts of the state.
What Are Maryland Air Quality Alerts?
Air quality alerts are public notices issued when pollution levels are expected to reach unhealthy levels for certain groups or, in some cases, the general public. In Maryland, the alerts are issued by the Maryland Department of the Environment, which produces three-day air quality forecasts for 10 regions of the state, according to the agency’s Air Quality Forecast page. Fine particle forecasts run year-round, while ozone forecasts run from April through September, when conditions are most likely to produce unhealthy ozone levels, the department says.
The goal of an alert is to give people time to adjust outdoor activities if needed, not to signal an emergency in every case. As the Maryland Department of the Environment puts it, “Air quality alerts do not eliminate traffic jams, shut down industry or turn off HVAC” — instead, they are meant to help residents make their own protective decisions based on local conditions, according to the department.
In Maryland, alerts are commonly associated with two main concerns:
- Ground-level ozone, which often develops during hot, sunny weather.
- Fine particles from wildfire smoke or other sources that can travel long distances and reduce air quality.
Maryland has experienced multiple real-world examples of these alerts in recent years. In June 2023, Gov. Wes Moore’s office issued a statement on a Code Red air quality alert after smoke from wildfires burning in Quebec, Canada, pushed pollution to unhealthy levels statewide, according to a press release from the Office of the Governor. At the time, the Maryland Department of the Environment advised residents to “consider limiting time spent outdoors and avoid prolonged or heavy exertion” while conditions persisted.
An alert does not necessarily mean everyone will experience health effects. Instead, it serves as a reminder to pay attention to current conditions and take appropriate precautions based on individual health needs.
Understanding The Air Quality Index
Air quality conditions are commonly communicated through the Air Quality Index (AQI), a measure developed by the U.S. Environmental Protection Agency (EPA). The AQI translates pollution measurements into six color-coded categories that are easier for the public to understand, according to the EPA’s AirNow.gov AQI Basics page:
- Green (0-50), Good: “Air quality is satisfactory, and air pollution poses little or no risk.”
- Yellow (51-100), Moderate: “Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.”
- Orange (101-150), Unhealthy for Sensitive Groups: Members of vulnerable populations may experience health effects, even though the general public is less likely to be affected.
- Red (151-200), Unhealthy: “Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects.”
- Purple (201-300), Very Unhealthy: A “health alert” meaning the risk of health effects is increased for everyone, per the EPA.
- Maroon (301 and above), Hazardous: A “health warning of emergency conditions” in which everyone is more likely to be affected, the agency says.
Generally, lower AQI values represent cleaner air, while higher values indicate increasing health concerns. As air quality worsens, recommendations become more protective, particularly for people who are more sensitive to air pollution.
Sensitive groups, as identified by the Maryland Department of Health and the EPA, can include:
- Children.
- Older adults.
- People with asthma or other lung diseases.
- People with heart disease.
- Pregnant people who have been advised by their health care provider to limit exposure to poor air quality.
Current AQI readings and forecasts for Maryland are publicly available through AirNow.gov’s Maryland state page, which is maintained by the EPA in partnership with state and local air quality agencies, along with many weather apps and smartphone services.
Smoke Versus Ozone: What’s The difference?
Although both can trigger Maryland air quality alerts, smoke and ozone affect the air in different ways.
Wildfire smoke contains tiny particles that can travel hundreds or even thousands of miles. Even if there are no fires in Maryland, smoke from distant wildfires can create hazy skies and reduce air quality, a pattern documented by the EPA’s Wildfire Smoke: A Guide for Public Health Officials, which is produced jointly with the Centers for Disease Control and Prevention (CDC) and other federal partners.
Ground-level ozone forms differently. According to the EPA’s Ground-level Ozone Basics page, it is “not emitted directly into the air, but is created by chemical reactions” between nitrogen oxides and volatile organic compounds from cars, power plants and other industrial sources when they react in sunlight — making hot summer afternoons more likely to produce elevated ozone levels. Unlike the protective ozone layer high in the atmosphere, the EPA notes that ground-level ozone is the main ingredient in smog and can irritate the lungs and make breathing more difficult. The agency also points out that ozone “can be transported long distances by wind, so even rural areas can experience high ozone levels.”
Because the causes differ, the timing of alerts may also differ. Smoke events often depend on wind patterns, while ozone alerts are more closely tied to weather conditions such as heat and sunshine, according to the Maryland Department of the Environment.
How Poor Air Quality Can Affect Your Health
For many healthy adults, brief exposure to moderately poor air quality may cause little or no noticeable effect. Others may experience symptoms such as coughing, throat irritation, watery eyes or shortness of breath.
People with asthma or other respiratory conditions may notice symptoms sooner. The EPA notes that people with asthma face some of the greatest health risks from breathing air with elevated ozone levels. Poor air quality can also make vigorous outdoor exercise more difficult, particularly during extended periods of elevated pollution.
Children warrant particular attention during smoke events, according to the CDC’s Wildfire Smoke and Children guidance, which notes that “children with asthma and chronic health issues may have more symptoms, including trouble breathing” during smoke exposure. Parents should remember that children often spend more time outdoors during play, making air quality an important factor when planning camps, sports practices and family outings.
Practical Steps To Protect Your Family
Checking the day’s air quality forecast can become as routine as checking the weather forecast.
If an air quality alert is in effect, the Maryland Department of Health and Maryland Department of the Environment recommend that residents “avoid prolonged or heavy exertion until air quality improves” and, on the worst days, “stay indoors as much as possible,” according to a joint public health advisory issued by the two agencies. Scheduling walks, yard work or exercise earlier in the morning may be helpful when conditions improve during part of the day, though actual conditions vary.
Keeping windows closed during periods of heavy smoke may help reduce indoor particle levels, and the state health department recommends using air conditioning to improve indoor air quality where available. If your home has a compatible air filtration system, using clean filters according to manufacturer recommendations may further help. On days with the poorest air quality, Maryland health officials have suggested that residents “consider wearing an N95, KN95 and FFP2” mask to reduce the particles they breathe in. The CDC cautions, however, that “dust masks, surgical masks, bandanas, and breathing through a wet cloth will not protect your child from smoke,” and that well-fitted, NIOSH-approved respirators are only recommended for children age 2 and older.
People who rely on medications for asthma or other breathing conditions should follow their health care provider’s guidance and have needed medications readily available; the CDC recommends keeping at least a seven-to-10-day supply on hand in a waterproof, childproof container ahead of smoke season.
State health officials also encourage residents to check on neighbors and relatives with chronic health conditions during periods of poor air quality. Families planning trips to parks, beaches or waterfront destinations in Southern Maryland or along the Chesapeake Bay may also benefit from checking both the weather forecast and the AQI before leaving home.
Staying Informed Across Maryland
Air quality can vary by location and can change throughout the day. Residents in Charles, Calvert and St. Mary’s counties may experience different conditions than those in Baltimore or the Washington metropolitan area, depending on weather patterns and pollution sources. The Maryland Department of the Environment breaks its forecasts into 10 separate regions of the state for this reason.
For the Washington, D.C., suburbs, the Metropolitan Washington Council of Governments also issues a daily regional air quality forecast through its Clean Air Partners program, a joint effort with state and local governments across Maryland, Virginia and the District of Columbia.
Residents can also sign up for free email or text alerts through AirNow’s EnviroFlash notification service, referenced on the Maryland Department of the Environment’s forecast page, in addition to checking local television forecasts, weather apps and official air quality reporting services. Checking these resources before outdoor events, youth sports or long periods of recreation can help families make informed choices.
Air quality alerts are intended to provide practical guidance rather than create alarm. Most pollution events are temporary, and conditions often improve as weather patterns change.
By understanding what Maryland air quality alerts mean, recognizing the difference between smoke and ozone and paying attention to the AQI, residents can better protect themselves while continuing to enjoy everything Maryland has to offer throughout the year.
Frequently Asked Questions
What is a Maryland air quality alert?
A Maryland air quality alert is a public notice, issued by the Maryland Department of the Environment, that pollution levels are expected to reach unhealthy levels for sensitive groups or, in some cases, the general public. It helps residents make informed decisions about outdoor activities.
Who should be most careful during poor air quality?
Children, older adults and people with asthma, lung disease or heart disease are generally more likely to experience health effects from poor air quality, according to the Maryland Department of Health and the EPA.
What is the difference between ozone and wildfire smoke?
Ground-level ozone forms during hot, sunny weather through chemical reactions between nitrogen oxides and volatile organic compounds, per the EPA. Wildfire smoke consists of tiny particles that can travel long distances from active fires, as documented by the EPA and CDC.
How can I check the Air Quality Index in Maryland?
Residents can check current AQI readings and forecasts through AirNow.gov, the Maryland Department of the Environment’s Air Quality Forecast page, the Clean Air Partners regional forecast, weather apps and many local weather forecasts before spending extended time outdoors.
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Is AG Brown and his cronies going to sue Canada over the smoke in Maryland? Maybe they could get some cash settlements, that they could skim from, like they usually do.