It's 9:40 p.m. on a weeknight, and more than 30 people are packed into Hookah Bookah on East Carson Street. The crowd is diverse and young, between 18 and 30. In a corner, a large group has gathered to share a few pipes.
"It's a cool thing to do to get out of the house," said Christina Markham, 20, of Shaler.
"It's such a good social gathering," Roxy Oglesby, 20, of Eighty Four, chimed in. "The first time I did it, I was at the beach with a ton of friends."
Ms. Markham and Ms. Oglesby, with seven others, are in the South Side bar to smoke a hookah -- a water pipe with hot coals that heat tobacco in an internal bowl. The tobacco comes in flavors ranging from raspberry to coffee, and its smoke is inhaled through a mouthpiece on the end of a hose.
With low, relaxed lighting and a distinctly flowery fragrance, the bars provide hookahs and tobacco for temporary use or permanent sale. Groups of people gather at small tables to share the pipes, sometimes for hours, paying about $7 each.
The scene is increasingly common in Pittsburgh, particularly among college students.
"It has become very popular in recent years, especially for people between the ages of 18 and 22," agreed Hookah Bookah manager Nauuas Alsreheen.
The practice also has begun to attract the attention of health professionals.
"Smoking tobacco with a hookah is becoming a major public health problem," said Brian Primack, director of the University of Pittsburgh's Program for Research on Media and Health. "While cigarette smoking is now decreasing, hookah tobacco smoking is increasing."
Mr. Alsreheen echoed that sentiment. "Lots of them quit cigarettes to smoke a hookah," he said Friday.
In April 2013, Dr. Primack and a group of researchers at Pitt's School of Medicine completed a study to determine the relationship between perceptions of hookah tobacco smoking and its use. Pitt released the study results last month.
The team was particularly interested in the moment of initiation -- or the first time someone decides to smoke.
Their work began after Dr. Primack and his colleagues found a statistic that 1 in 5 undergraduates reported hookah tobacco smoking within the previous year. The researchers, with National Cancer Institute support, surveyed 569 underclassmen and graduate students at the University of Florida twice in a seven-month period.
The findings showed that within the seven months, 13 percent of the people began to smoke hookahs.
Furthermore, they found that students with better opinions of hookah use were more likely to smoke, while undergraduates with negative views of the water pipe had significantly decreased odds of using it.
In its conclusions, the team raised concerns about the increased prevalence of hookah use, public unawareness of its addictive and toxic properties, perceived social benefits to smoking and a lack of regulation.
The group at Hookah Bookah recounted rite-of-passage experiences that mirrored the team's findings.
"The first time I smoked, I was 18," the age at which tobacco use is legal, said John Vamos, 20, of Eighty Four.
"Same. When I turned 18, I came here," said Maura DiDomenicus, 20, of Shaler.
Carbon monoxide, nicotine, carcinogens and tar accompany the hookah high, but more frightening than the biochemistry is another reality: The students don't seem to realize the health risks.
A study that Dr. Primack and his colleagues referenced revealed an alarming lack of knowledge about hookah-smoking dangers.
When the students in that study were asked about the comparative harm of cigarettes and water pipes, more than half knew nothing about the hazards.
"I think that college students are going to be very surprised when they learn more about the toxins," said Dr. Primack. "Compared with cigarette smoking, hookah tobacco smoking feels much less harsh to users because of the water and flavorings involved."
The smokers at Hookah Bookah can attest to that.
"This tastes good. Cigarettes burn your lungs," Ms. DiDomenicus said.
Blaine Kubicsek, 20, of Shaler agreed. "You get the same buzz a cigarette would give you, but it doesn't seem as harsh," he said.
But it is just as dangerous, Dr. Primack said: "This behavior still exposes the user to the same toxins as cigarette smoking."
Another element cited in the Pitt research showed that students believe hookah tobacco smoking is less addictive than cigarette use.
"Once you smoke cigarettes, you get addicted," Ms. Oglesby said. "This feels much safer."
Dr. Primack and his colleagues also worry about the group aspect of smoking. When asked whether any of them would go alone, the Hookah Bookah patrons exchanged looks and laughed.
"That would be weird," one of the young men responded.
Many hookah users spend an entire evening around the pipe. Such duration also worries Dr. Primack, who estimated that the volume of smoke inhaled in a hookah session is 100 times greater than that from a one cigarette.
Mr. Vamos acknowledged that aspect. "Yeah, you wouldn't smoke a cigarette for an hour," he said.
"I have some regulars who come in every day for three or four hours, but on average, people probably smoke for an hour and a half," Mr. Alsreheen said.
The Pitt researchers said new anti-smoking strategies are needed to reduce hookah use.
Dr. Primack said that smoking has become so socially acceptable that they are calling for initiatives aimed to "combat positive perceptions of hookah use as attractive and romantic."
They also cite a need for clearer policy and regulations. In Pennsylvania, there are no hookah-specific laws.
Emma Brown: firstname.lastname@example.org or 412-263-3778.