Yareli Sanchez lives in Los Angeles and jogs regularly, but she never used to know if the day’s air quality was bad until after she had already set out for a run — her chest would tighten and it would become hard to breathe. She knew poor air quality triggered her asthma, but she didn’t have a convenient way to check the day’s pollution levels.

For the past few months, instead of using trial-and-error, she’s checked UCLA’s new AirForU app, which uses GPS data to give her local air quality ratings. The app is useful for anyone in the U.S. who sees a hazy skyline and wonders how safe it is to breathe outside air.

“I depend on the AirForU app now, and I use it every time I plan on running,” said Sanchez, who helped test it before its launch. “The app is really convenient for helping me manage my asthma and minimize my exposure to pollution.”

A new NASA-led analysis of a moderate magnitude 5.1 earthquake that shook Greater Los Angeles in 2014 finds that the earthquake deformed Earth's crust across a broad region encompassing the northern Los Angeles Basin and northern Orange County. The shallow ground movements observed from this earthquake likely reflect strain accumulated on deeper faults, which remain locked and may be capable of producing future earthquakes.

A team of NASA and university researchers led by geophysicist Andrea Donnellan of NASA's Jet Propulsion Laboratory, Pasadena, California, used GPS and NASA airborne radar data to measure surface deformation in Earth's crust caused by the March 28, 2014, earthquake, which was centered in La Habra, California. The earthquake was felt widely in Orange, Los Angeles, Ventura, Riverside, San Bernardino, Kern and San Diego counties. While the earthquake was relatively moderate in size, the earthquake's depth (3.6 miles, or 5.85 kilometers) and location within a highly populated region resulted in more than $12 million in damage. Most of the damage occurred within a 3.7-mile (6-kilometer) radius of the epicenter, with a substantial amount of damage south of the main rupture.

A global ocean lies beneath the icy crust of Saturn's geologically active moon Enceladus, according to new research using data from NASA's Cassini mission. 

Researchers found the magnitude of the moon's very slight wobble, as it orbits Saturn, can only be accounted for if its outer ice shell is not frozen solid to its interior, meaning a global ocean must be present. 

The finding implies the fine spray of water vapor, icy particles and simple organic molecules Cassini has observed coming from fractures near the moon's south pole is being fed by this vast liquid water reservoir. The research is presented in a paper published online this week in the journal Icarus.

Tattoos really are more than skin deep—and that raises questions about their safety.

Many people enjoy the aesthetic beauty of tattoos. But the brightly colored inks that make tattoos so vibrant and striking also carry health concerns, report authors of a new paper related to tattoo safety.

According to the Pew Research Center, 45 million Americans have at least one tattoo; roughly $1.65 billion is spent on tattoos each year in the U.S.

This week, EPA Administrator Gina McCarthy joined private and public sector leaders for a second annual White House roundtable discussion about the progress made and new steps taken to curb emissions of hydrofluorocarbons (HFCs), potent greenhouse gases used in refrigeration and air conditioning. Administrator McCarthy announced several new actions the agency will take to help support a smooth transition to climate-friendly alternatives to HFCs.

"EPA is working closely with industry leaders to reduce greenhouse gas emissions, transition to climate-friendly refrigerants, and deploy advanced refrigeration technologies,” said EPA Administrator Gina McCarthy. “The powerful combination of EPA’s regulatory actions and innovations emerging from the private sector have put our country on track to significantly cut HFC use and deliver on the goals of the President’s Climate Action Plan.”

Although researchers have known since 1999 that traces of the Ebola virus could remain in semen for months, two papers published in The New England Journal of Medicine today offer more detail about the frightening possibility that survivors of an infection could rekindle outbreaks. One study focuses on nearly 100 men in Sierra Leone who survived the dreaded viral illness, whereas the second one documents a clear case of sexual transmission of Ebola virus.

In the Sierra Leone study, researchers found Ebola viral RNA in semen samples from almost half the 93 men they tested.  The likelihood of finding viral RNA declined as time from disease onset increased: All nine men who were tested 2 to 3 months after they fell ill had evidence of Ebola RNA in their semen, but the researchers  found it in only 26 of 40 men whose infections had started 4 to 6 months earlier and in 11 of 43 men whose infections had started 7 to 9 months earlier. The result from one Ebola patient tested 10 months after disease onset was indeterminate.

Ever since human beings first began climbing the world's tallest mountains, they have struggled with a basic problem: altitude sickness, caused by lower air pressures which affect the ability of our bodies to take up oxygen. 

Or, as actor Jason Clarke says in his role as the climbing guide Rob Hall in the recently released movie, Everest, "Human beings simply aren't built to function at the cruising altitude of a 747." 

Higher temperatures result in Swedish sand lizards laying their eggs earlier, which leads to better fitness and survival in their offspring, according to research published in the open access journal BMC Evolutionary Biology.

The findings indicate that climate change could have positive effects on this population of high-latitude lizard, but the authors warn that climate change is likely to affect a whole suite of traits, in addition to egg-laying date, which together would have an unknown combined effect on survival and reproductive success.

Making predictions about climate variability often means looking to the past to find trends. Now paleoclimate researchers from the University of Missouri have found clues in exposed bedrock alongside an Alabama highway that could help forecast climate variability. In their study, the researchers verified evidence suggesting carbon dioxide decreased significantly at the end of the Ordovician Period, 450 million years ago, preceding an ice age and eventual mass extinction. These results will help climatologists better predict future environmental changes.

The Ordovician geologic period included a climate characterized by high atmospheric carbon dioxide (CO2) levels, warm average temperatures and flourishing life. Near the end of the period, CO2 levels dropped significantly but precisely when and how fast is poorly known. Kenneth MacLeod, a professor in the Department of Geological Sciences in the MU College of Arts and Science, directed a research team studying the climate changes 450 million years ago to better understand the interactions among the biosphere, the oceans, atmospheric CO2 levels, and temperature.

A new study from the team behind NASA's Mars Science Laboratory/Curiosity has confirmed that Mars was once, billions of years ago, capable of storing water in lakes over an extended period of time.

Using data from the Curiosity rover, the team has determined that, long ago, water helped deposit sediment into Gale Crater, where the rover landed more than three years ago. The sediment deposited as layers that formed the foundation for Mount Sharp, the mountain found in the middle of the crater today.