HILO, Hawai'i — With emissions from Kilauea volcano regularly exceeding federal air pollution standards in parts of the Big Island, residents and visitors breathing the stuff wonder what that does to their health.

The answer isn't simple. The huge amounts of particulates and sulfur dioxide spewing out of the volcano can quickly cause problems for people who have respiratory ailments such as asthma, said health officials. But they say the long-term effects on healthy people aren't as clear.

The state Health Department and Hawai'i County officials are being peppered with inquiries about the long-term effects of the emissions on children and adults. Big Island Mayor Harry Kim said those concerns are "very understandable and very justified."

To illustrate the difficulty of getting answers, Kim reminded people of the years it took to scientifically prove the health hazards of smoking.

"Nobody knows the long-term effects of many, many things because it takes long-term studies to know the long-term effects of it," Kim said. He said county officials have been meeting with the Health Department, and "that is being reviewed and researched to see what they need to do to find out the answer to those things."

Steve Drogin, a part-time Kona resident, said people are talking about the vog and its possible health effects, and are more concerned about it than at any time he can recall since he first came to Hawai'i in the 1980s.

The haze blots out the view of the ocean, some athletes have decided not to exercise outside on bad days and almost everyone in West Hawai'i has been affected in some way, he said.

"It is thicker and it is much more invasive than ever before," Drogin said. "It is affecting more people's lives than ever before."

Barbara Brooks, a toxicologist for the Department of Health's Hazard Evaluation and Emergency Response Office, said the past nine years of studies of the effects of volcanic emissions have been "inconclusive."

There has been research into the long-term effects of sulfur dioxide and particulates from industrial air pollution, but those emissions aren't the same as the emissions from the volcano, and determining what causes a particular health effect is a complex business.

Even the research into long-term health effects of emissions from other volcanoes isn't much help because of variation in the emissions among volcanoes, said Dr. Elizabeth Tam, a professor and chair of the department of medicine in the University of Hawai'i's John A. Burns School of Medicine.

"The volcanoes are all different," said Tam, who is conducting a study of respiratory problems among about 1,900 Big Island youngsters, including 300 to 400 with asthma. "Kilauea is quite unique in that it's almost purely sulfur dioxide (emissions), and it has been going so darn long."

TOO MANY VARIABLES

There is little long-term research into the effects of volcanic particulates and sulfur dioxide at the levels present on the Big Island, and none that covers an eruption time frame comparable to Kilauea's ongoing 25-year eruption.

Another complication is the sudden change in the volume of emissions. Most Kilauea research, including Tam's study, focuses on a time when the primary source was Pu'u 'O'o, which is far from Big Island population centers in a remote area of Hawai'i Volcanoes National Park.

Late last year that changed when Halema'uma'u at the Kilauea summit began to produce more gas, and burst open a new vent on March 12 that is much closer to populated areas such as Volcano Village.

Since then, the combined emissions from Kilauea have been running 150 percent to 200 percent of normal, and residents notice the difference.

The most recent measurements by the U.S. Geological Survey showed Pu'u 'O'o was producing about 2,860 metric tons of sulfur dioxide on May 11, while Halema'uma'u was producing about 810 metric tons on May 12, about quadruple the normal background emissions for the summit.

Generally the winds tend to push the gases away from population centers. Last week, the tradewinds were pushing sulfur dioxide from the vents at Pu'u 'O'o and Halema'uma'u southwest toward Pahala, and nudging particulates around the flank of Mauna Loa to linger over Kona.

This is a common weather pattern that caused emission levels in Pahala to exceed federal pollution standards a dozen times since April 1.

Last week, light winds from the south allowed thick vog to collect over much of the rest of the Big Island and to drift up the island chain, while conditions improved in Pahala and Kona. The vog did not exceed federal pollution standards last week, but similar winds caused emissions to exceed federal pollution standards for particulates and sulfur dioxide in Mountain View on April 24 and 25.

NOT SMOG

There is research all over the world into the effects of airborne particulates from auto exhaust and industrial plants, but those particles aren't the same as the particles in vog. The environments in those urban areas also tend to be loaded with other pollutants such as nitrogen oxides and ozone, which isn't the case on the Big Island.

Most of those urban studies found that people living for many years in areas with high particulate levels suffered more often from reduced lung function, development of chronic bronchitis and even premature death among the elderly, Brooks said.

As for sulfur dioxide, the Environmental Protection Agency last year concluded the epidemiological studies on sulfur dioxide "provide inconclusive evidence that long-term exposure to sulfur dioxide has adverse health effects."

However, Brooks noted that the research the EPA was evaluating involved sulfur dioxide in conditions unlike Hawai'i's because that research did not include the volcanic particulates mixed with the sulfur dioxide here. If there were some interaction between the sulfur dioxide and volcanic particulates that does have a health effect, the research reviewed by the EPA wouldn't reflect that.

Tam's study of Big Island children, which is the largest local study, will gather data on the possible health effects from the higher levels of emissions later this year, including research involving schoolchildren at Volcano Village.

"That is information we need," Brooks said.

A study of 335 Big Island adults done in 2004 and released earlier this year did offer clues there may be health effects from the combined emissions. That study compared a group of residents who had lived at least seven years in the Ka'u area exposed to vog and sulfur dioxide with an unexposed group in Hawi.

It found that those exposed to volcanic emissions reported higher rates of sore throats, runny noses and coughs — no surprise to Hawai'i residents — but also found faster pulse rates and higher blood pressure in the exposed group.

Bernadette Longo, one of the authors of the study and an assistant professor of nursing at University of Nevada-Reno, said it is the first research in the world to document health effects of volcanic emissions on the heart and lungs, but added that "one study is just one study. It needs to be multiple studies that are conducted in different ways" to prove any health effects, she said

HOSPITAL CLUES

Now state health officials are trying to get a better fix on short-term health effects from the higher levels of Kilauea emissions by monitoring medical emergencies.

Sulfur dioxide and particulates can cause breathing problems in people with respiratory problems such as asthma, emphysema, and bronchitis, but so far Ka'u Hospital downwind of Kilauea is the only hospital to report higher-than-normal numbers of patients with respiratory problems.

Ka'u has reported a 50 percent increase in hospital and clinic cases of that type, which for a small facility like Ka'u means about one extra case per day.

For the past two weeks, the Health Department has been monitoring emergency rooms on the Big Island and emergency calls to paramedics to watch for cases of severe respiratory distress that correspond to days where there are heavy volcanic emissions in particular communities, Brooks said.

"That's the kind of information we need, and that's the kind of information we're getting," Brooks said. "Anecdotally, we're hearing that people really are being affected, but we can't tell from the emergency room visits at this point because we haven't been monitoring them long enough."

Tam, who is about six years into the long-term study of Big Island children, said her research so far actually suggests children are more likely to report they have been diagnosed with asthma if they live upwind of the volcano, meaning they would be less affected by the emissions.

Those preliminary results show that smoking in the home "does seem to be correlating much better with the asthma rate than anything else. It's so complicated, it was a lot more complicated than we thought it would be."

"The lesson in all of this is when you get all excited about a natural cause of air pollution, we ought to focus on some of the things we're doing," she said. "Those are things we can change."