Even a decade later, when she hears of a shooting rampage or a building being bombed, Jane El Farra holds her breath.
Since Sept. 11, 2001, El Farra cannot help but wonder: Were Muslims involved?
"I was devastated," said El Farra, who is Muslim and a former member of the Valley Interfaith Council board in the San Fernando Valley. "To find out that people who claimed to be Muslim did this was horrifying."
The terrorist attacks of 9-11, which killed nearly 3,000 people on the East Coast, sent change coursing deeply through the daily lives and lifestyles of people nationwide and around the world.
Travel restrictions were tightened. Police presence was increased. Anger and anxiety emerged. Distrust surfaced - but volunteerism and a need for kinship also arose.
"When we saw the two airliners run into the twin towers, that's a sight I'll never forget," said Los Angeles Airport Police Chief George Centeno. "That was a realization our world had changed."
Los Angeles International Airport now spends $126 million a year just on security and safety, Centeno said.
Rings of security encircle LAX, from vehicle checkpoints at the entrance to the addition of 139 police officers and 155 security officers since 2001. The airport also boasts the nation's largest unit of bomb-sniffing dogs, Centeno said.
Despite that, LAX was - and remains - the top terrorist target on the West Coast, he said.
"As we approach the 10-year anniversary, our job isn't done," Centeno said. "The 10-year anniversary is going to come and go and, when it does, we're still going to have to protect our airports."
For LAPD Cmdr. James Cansler, not a day goes by without his thinking about terrorism. Whether supplementing security at a football game at the Rose Bowl in Pasadena or patrolling festivals, Cansler said officers implement the same tactics of caution.
Before 2001, a brushfire or a train crash was simply an unfortunate tragedy. Today, police consider whether there is a possible link to terrorists, Cansler said.
"Now, when someone calls in a suspicious package, we send in the bomb squad and roll out a Code 3," or a high-priority emergency response, Cansler said. "Before (9-11), we'd go and pick up the package ourselves."
The terrorist attacks even changed the make-up of public safety departments.
Los Angeles County Sheriff Lee Baca said his department now has 500 volunteers and sworn officers who speak Arabic.
Along with the increase in public safety, a new kind of anxiety emerged, said Los Angeles-based therapist John Tsilimparis.
The Sept. 11 attacks were followed by wars in Iraq and Afghanistan. Alongside them came a dwindling economy, high unemployment and constant images of natural disasters such as tornadoes, hurricanes, earthquakes and tsunamis.
"The collective anxiety has changed in light of a decade of many overwhelming events," Tsilimparis said. "The last 10 years we've been able to watch all these events on our smartphones. It's been the type of decade when the baseline for people's anxiety has risen. This heightened sense of vulnerability also has risen."
He tells patients that while they can't control the government or natural disasters, they can find peace by focusing on what they can change, such as relationships or jobs.
There were 188 hate crimes reported in Los Angeles County in the first three weeks after 9-11, said Marshall Wong, coordinator of anti-hate crime programs for the L.A. County Human Rights Commission.
"People were called terrorists, were attacked on the street without provocation, and there were many cases of vandalism," Wong said. "A large number of those crimes were of mistaken identity. Victims included many people who were neither Muslim nor Middle Eastern."
El Farra said she didn't experience any such crimes, but her daughter, who wears a hijab, or headdress, has.
After 9-11, El Farra and her friends decided to make a remembrance quilt in honor of those who died in the attack. It symbolizes a message to the families of those who perished: Their pain is our pain.
From the horror of that day when so many lives were lost arose a need to give, said David Levinson, who founded Big Sunday, the largest volunteer event in the nation.
"On the face of horrible tragedy, it's people's love and compassion for each other that gets us through the day," Levinson said.
Since 9-11, more people have volunteered their time, Levinson said. At a time when politics and other extremists want to emphasize differences, people want something else, Levinson said.
"I think people want to focus on what unites us," Levinson said. "Most people are nice and good-hearted."