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.
The EPA’s effort to remove lead from gasoline saved a lot of infant lives.
Kimberly White KW/DH via Reuters
An extensive amount of research has shown a direct link between air quality and fetal and infant health. Cleaner air has saved lives – and money.
The Flint water crisis was one of the few cases of environment-related social injustices that reached national attention in recent years.
AP Photo/Andrew Harnik
Addressing social and health inequalities from pollution is no longer a priority at the EPA. What did the Office of Environmental Justice do and what will happen if it's shut down?
Prairie potholes in South Dakota are important breeding and feeding areas for many types of birds. Under the Clean Water Rule, farmers cannot fill them in or discharge pollutants into them without a permit.
Laura Hubers, USFWS/Flickr
President Trump signed an executive order to roll back the 2015 Clean Water Rule. Two water experts explain why the rule alarms farmers and ranchers concerned about over-regulation.
New research shows that exposure to fine particulate air pollution may double the risk of dementia in older women by increasing growth of beta-amyloid plaques in the brain.
Regulators test soil for hazardous chemicals at a brownfield cleanup site in West Seneca, New York.
We may picture regulators tying businesses up in red tape, but research shows that many environmental regulators have collegial relationships with the companies they regulate.
Uncertainty around government policy affects how businesses operate and whether they’ll invest in R&D.
Economists have shown, using both theory and data, that uncertainty about U.S. environmental policies makes clean tech innovation less likely.
EPA personnel collect water samples along the Louisiana coast after the 2010 Deepwater Horizon oil spill.
Eric Vance, US EPA/Flickr
President-elect Donald Trump has pledged to decimate the Environmental Protection Agency. But a political scientist predicts that while EPA will face budget cuts, the agency isn't going anywhere.
What’s in that bottle? And is it safe?
Congress has passed a long-overdue update of a key law regulating hazardous chemicals. But a legal scholar says the new law does not go far enough to reduce chemical exposure risks.
Factory smokestacks, Milwaukee, Wisconsin.
Do environmental regulations help or hurt the economy? Ask the Republican and Democratic presidential candidates and you'll get starkly different views.
US President Barack Obama has unveiled the United States’ most comprehensive climate policy so far.
US President Barack Obama's new climate plan aims to cut greenhouse emissions from the nation's coal-dominated power sector by 32% by 2030. Will it get through, and how will it affect this year's climate talks?