Vehicles are a major source of particulate air pollution.
Scientists who were appointed to advise the EPA on air pollution kept meeting independently after the agency dissolved their panel. They say current regulations aren't strict enough.
Many migratory birds, like these sandhill cranes, rely on wetlands for feeding, resting and shelter.
A 2006 Supreme Court ruling created widespread confusion about which wetlands and other waters are federally protected. The Trump administration's latest action isn't likely to clear things up.
Bottled water distribution in Glenwood, Iowa, where massive spring flooding along the Missouri River disrupted drinking water treatment, April 3, 2019.
AP Photo/Nati Harnik
A grade of 92 is an A at most schools, but for tap water it means that millions of Americans drink water that fails to met federal standards.
Oil refineries and other industrial sources in and around Houston create some of the highest ozone levels in the nation.
AP Photo/Pat Sullivan
Air quality in the US has improved greatly since 1990, but a new report finds progress stalling in some cities. Meanwhile, the Trump administration is rolling back air pollution controls.
Hoosick Fall, N.Y. is one of many U.S. communities whose drinking water has been contaminated with PFOA or PFOS.
AP Photo/Mike Groll, File
EPA is moving to regulate two chemicals from a group called PFAS that are contaminating drinking water. A public health expert explains why the agency should take much broader action.
Industrial facilities like this oil refinery in Anacortes, Washington are significant air pollution sources.
An air pollution expert with years of experience advising federal regulators describes how the Trump administration is speeding up reviews and reducing scientific input.
A half-century of regulation has greatly increased the fuel efficiency of US-made cars.
Do high fuel economy requirements make the US auto fleet less safe? The Trump administration says yes and is moving to freeze these standards, but auto experts and US car makers disagree.
A study finds that higher ozone levels correlate with slower performance times for college endurance athletes.
US ozone pollution has fallen in recent decades, but exposure to low levels of ozone still has serious effects on human health and well-being.
Rep. Dan Kildee, D-Mich., speaks about EPA Administrator Scott Pruitt and the state of the EPA during a protest on April 25, 2018, in Washington.
AP Photo/Alex Brandon
After two years of turmoil at the EPA in the 1980s, President Reagan hit the reset button, choosing a Republican who supported environmental protection to head the agency.
Tighter emissions standards create costs for truck manufacturers yet provide health benefits for society. How should they be weighed?
EPA Administrator Scott Pruitt has proposed steps that would reduce economic benefits to society from new regulations. An economist who worked for Presidents Clinton and Obama calls this a strategy to justify deregulation.
Protesters at a rally on the state of the EPA organized by the American Federation of Government Employees union, April 25, 2018, in Washington, D.C.
AP Photo/Alex Brandon
Government agencies are supposed to listen to the industries they regulate, but what if they tune out everyone else? Scholars call this regulatory capture, and some staffers see it happening at EPA.
Smog alert in Cleveland, Ohio, July 20, 1973.
EPA Administrator Scott Pruitt wants to change the grounds for setting US air pollution targets. An environmental lawyer explains why Pruitt's approach misreads the law and could roll back decades of gains.
The landmark Harvard Six Cities study found a strong link between air pollution and health risks.
The EPA intends to limit what scientific studies can inform policy – a change long sought by industry. A long-time public health researcher explains the single study at the root of the controversy.
March for Science in Portland, Oregon, April 22, 2017.
The March for Science on April 14 and Earth Day on April 22 are likely to generate big crowds demonstrating against Trump administration policies. Here are some issues they'll be marching about.
Healthy aquatic vegetation in the Chesapeake Bay.
Cassie Gurbisz/University of Maryland Center for Environmental Science
An ambitious plan to cut the flow of nutrients into the Chesapeake Bay has produced historic regrowth of underwater seagrasses. These results offer hope for other polluted water bodies.
Fracking has led to an increase in truck traffic, one of the reasons for worsening trends on air quality in areas with oil and gas drilling.
AP Photo/Charles Rex Arbogast
The fracking boom has led to a large increase of hydrocarbon emissions in rural areas, reversing some regional air toxics trends.
To comply with air pollution laws, midwest energy companies built tall smokestacks to displace pollutants. This one at Indiana’s Rockport Generating Station is 1,038 feet high, just 25 feet shorter than the Eiffel Tower.
Trump administration officials argue that states can regulate more effectively than the federal government. But without leadership from the top, federalism may allow red states to avoid acting.
Harmful algae bloom in Lake Erie, Oct. 13, 2011.
NASA Earth Observatory
Nitrogen and phosphorus are polluting US waters, creating algae blooms and dead zones. New research confirms that voluntary steps are failing in the Gulf of Mexico and unlikely to work in Lake Erie.
Scientists provide key input to government agencies on issues such as improving oil spill prevention and response after the 2010 Deepwater Horizon disaster.
U.S. Coast Guard
Can federal agencies stack advisory panels with friendly members? Some have tried, but a scientist who has advised many administrations says they will produce bad policies that lack broad support.
Snow geese settle on a wetland in North Dakota. If the Trump administration successfully rescinds the Clean Water Rule, many wetlands might lose federal protection.
Krista Lundgren USFWS/Flickr
The Clean Water Rule spells out which streams, wetlands and other water bodies receive federal protection. The Trump administration wants to repeal it, but will face high hurdles in court.