Perch raises $30M from Nuveen to expand access to community solar savings for all Read >

Tackling Pollution In Delaware: How To Help

Delaware is one of the most polluted states in the U.S. Agriculture, industry, gas-burning vehicles, and wildfire smoke all damage the state’s natural environment. The state government is working to clean up this pollution—and individual Delawareans can help, too.
Bethany Beach, Delaware

Pollution is the name for any kind of harmful substance being introduced into the environment. These harmful substances, known as pollutants, can affect all parts of the natural world—air, water, and land. Some forms of pollution, such as wildfire smoke, occur naturally. But most pollutants, from car exhaust in the air to microplastics in the ocean, are the result of human activities.

Pollution poses a threat to all living things, including humans. We can become sick from breathing polluted air, drinking polluted water, or eating food grown in polluted soil. Pollution can even affect the climate of our entire planet. Climate change, driven by pollutants called greenhouse gases, makes extreme weather more common which makes it harder for people everywhere.

How much pollution is there in Delaware?

The First State is not quite first in the nation when it comes to pollution—but it’s close. According to the 2023 Best States ranking by US News, Delaware is the third-most polluted state in the country. This doesn’t harm residents as much as you might expect; the state’s air and water quality are actually above average. But pollution’s toll on the natural environment still affects Delawareans’ quality of life.

Water pollution  

Every year, the U.S. Environmental Protection Agency (EPA) rates the safety of water bodies in each state. Its 2022 report for Delaware was mostly bad news. Most of the state’s lakes and coastal waters were safe for swimming, but most rivers and streams were unsafe. A majority of rivers, lakes, and coastal waters were unable to support healthy aquatic life. And fish caught anywhere in Delaware were most likely unsafe to eat.

Fortunately, Delaware does a good job of keeping pollutants out of its drinking water. According to US News, the state had just 0.83 points of EPA drinking water violations per 100,000 residents. That’s much lower than the nationwide average of 1.91 points per 100,000 residents.

Air pollution  

Two air pollutants that harm human health are ozone and fine particles. Ozone forms when other pollutants, including nitrogen oxides (NOx) and volatile organic chemicals (VOCs), react with sunlight. Both pollutants can contribute to heart disease and a wide variety of lung problems, from asthma to lung cancer.

An annual report by the American Lung Association (ALA) grades every U.S. county on its levels of these two pollutants. In the latest report, Delaware got mixed results. None of its three counties scored below a B for particle pollution, but one county got a D for ozone.

Land pollution 

The EPA monitors pollution levels on land through its annual Toxic Release Inventory (TRI). It lists all major releases of harmful chemicals in each state and whether they affected the air, water, or land. In 2021, Delaware’s total toxic releases came to 6.9 million pounds, including 601,700 pounds on land. For a state this small, that’s a very large amount. Delaware’s total releases per square mile were the third highest in the entire country.

Land polluted with plastic water bottles and litter

What are the biggest causes of pollution in Delaware?

Delaware’s pollution problems aren’t all home-grown. Air pollutants can blow downwind into Delaware from other states and even from as far away as Canada. Over 90% of ozone pollution in Delaware comes from outside the state. But much of the state’s pollution is due to various factors within Delaware—from road traffic to industry.

Vehicle emissions

Transportation—both in Delaware and upwind of it—is the single biggest source of air pollution in the state. Vehicles burning gasoline and diesel fuel emit NOx and VOCs, which turn into ozone. NOx and sulfur dioxide (SO2) from cars can also react with other gases to create particle pollution. And fossil fuel burned in car engines releases greenhouse gases such as carbon dioxide, contributing to climate change.

Smokestack emissions

Factories, refineries, chemical plants, and power plants burning fossil fuels all contribute to air pollution. Their smokestacks belch out NOx, SO2, greenhouse gases, VOCs, and a variety of other pollutants. Smokestacks can contribute to water and land pollution as well. Coal-fired power plants release mercury, which eventually lands in the water or soil. Over 90% of Delaware’s coastal waters contain mercury.

Smokestack pollution


Agriculture is one of Delaware’s biggest industries—and also one of its biggest polluters. Pesticides, fertilizer, and bacteria from factory farms and slaughterhouses all wash into the state’s waterways. One major problem is farmers watering their fields with wastewater, which often contains fecal bacteria. In 2021 Mountaire Farms, a major poultry producer, was forced to pay $65 million for contaminating nearby residents’ drinking water.

Chemical waste

Another major Delaware industry, chemical manufacturing, also contributes to the state’s water woes. Waste products from the state’s chemical plants have polluted the state’s rivers, lakes, and coastal waters. In 2021, three chemical companies agreed to pay Delaware $50 million for polluting its waters with Polyfluoroalkyl Substances (PFAS). Other pollutants associated with chemical manufacturing include dioxins and polychlorinated biphenyls (PCBs).


Smoke from open fires is a source of both ozone and fine particle pollution. Besides harming human health, particle pollution also affects the health of water, soil, farm crops, forests, and other ecosystems. The First State has banned most open burning during “ozone season,” May 1 through September 30. However, it can’t block out smoke from other areas. In 2023, smoke from wildfires in Canada repeatedly drove Delaware air quality into the “unhealthy” range.

Most and least polluted areas in Delaware

The most polluted part of the First State is the northern region around Wilmington, its largest city. It’s part of the larger Philadelphia metro area, which has some of the worst air pollution in the nation. Wilmington’s home, New Castle County, got the worst grades for both ozone and particle pollution in the ALA report. It also had by far the largest number of toxic releases on the TRI.

The cleanest part of the state is a little harder to pin down. Sussex County in the south appears to have the cleanest air. The ALA gives it top-notch grades, reporting that it had zero days with bad air quality in 2022. However, Sussex County had 15 total toxic releases on the TRI, while centrally located Kent County had only 10.

How does pollution affect Delaware residents?

Pollution harms Delaware residents’ health and quality of life in a variety of ways. Air pollution contributes to a variety of lung diseases and also worsens heart disease. Pollutants in the water can also cause many illnesses, including cancer, and can spread infectious diseases. Pollution blankets the landscape in smog and makes the state’s waterways unsafe for drinking, fishing, and swimming. It damages buildings with soot stains and erodes them with acid rain.

But the most serious problem of all for Delaware is the threat of climate change. Rising global temperatures will make extreme weather, like heat waves and severe storms, more common. Heat-related illness, erosion, and flooding will all occur more often. And as polar ice melts, sea levels will rise, threatening access to beach communities. Even the Port of Wilmington could see its main facilities disappear beneath the waves.

Pollution and environmental justice

The dangers of pollution aren’t spread evenly across the state. Certain groups—particularly people of color and people living in poverty—suffer more from its effects. Members of these groups are much more likely to live in highly polluted areas, such as near chemical plants. They also have less access to high-quality health care that could protect them from pollution’s harms.

A 2017 study compared low-income, minority neighborhoods in New Castle County with other parts of Delaware. It found that people in those neighborhoods had more exposure to pollution and higher rates of cancer and respiratory illnesses. That makes remedying pollution in these areas a matter of environmental justice, necessitating protecting those who bear the greatest burden.

Tesla electric car on pavement.

What’s being done to clean up Delaware?

Delaware’s state government, together with businesses and nonprofits, is working to clean up pollution throughout the First State. Projects under way include:

  • Clean car incentives. The state of Delaware has several programs to help residents switch to electric vehicles (EVs) and other cleaner vehicles. It offers rebates on the purchase of EVs and grants for businesses and public places to install EV chargers. And it’s working on a plan to build charging stations along highways with help from the federal government.
  • The Clean Water Trust. The $50 million Delaware Clean Water Trust was established in 2021. The money in the trust is dedicated to protecting Delaware’s waterways from pollution and improving the state’s drinking water system. The law that created it also has an EJ component, dedicating a share of the funds to improvements in low-income communities.
  • Delaware Coastal Cleanup. Every year, volunteers across Delaware help clean up trash along the state’s beaches and in its waterways. There are individual cleanup sites in state parks, wildlife preserves, and beaches throughout the state.
  • Climate Action Plan. In 2021, Delaware passed a Climate Action Plan to help the state deal with climate change. Part of this plan focuses on reducing greenhouse gas emissions to keep climate change under control. It calls for the state to scale up clean energy production, increase energy efficiency, and speed the transition to EVs. There’s also a focus on preserving forests, wetlands, and urban green spaces that act as carbon sinks.
  • Community solar. Delaware passed its first law enabling community solar—residents sharing the output from a small solar farm—in 2010. In 2021, it amended this law to increase the maximum size of community solar installations. It also required 15% of all community solar shares to go to low-income customers.
Sun shining on solar panels

How you can contribute to a cleaner Delaware

There are many ways for individual Delawareans to help with the state’s pollution problems. For instance, you can take part in the annual Delaware Coastal Cleanup to remove trash from beaches and waterways. In between cleanups, you can pick up trash near your home and when out hiking. Take recyclable items home to put in your bin and toss the rest in the nearest trash can.

One really easy way to help expand renewable energy is to sign up for community solar. Perch makes it easy to find a nearby community solar project that can get you a discounted electric bill.

You can also reduce air and water pollution by cutting your use of fossil fuels. One way to do this is to save energy at home. That could mean adjusting your thermostat, adding insulation, eliminating phantom power use, or upgrading to energy-efficient lightbulbs and appliances. On the road, you can reduce gasoline use by driving less or switching to an EV—or both.

Get matched to a local solar farm and save on your electricity costs.