Study: Vog can trigger asthma

By CHELSEA JENSEN

Stephens Media

Vog doesn’t necessarily cause asthma, but it can trigger an episode, a 10-year study of vog’s impact on Big Islanders’ health continues to show.

“Whether vog causes asthma we have not found a direct correlation to that,” said Elizabeth Tam, Hawaii Island Children’s Lung Assessment Scientific Study leader and a pulmonologist with the University of Hawaii at Manoa John A. Burns School of Medicine. “But, certainly it does exacerbate asthma.”

In fact, children residing outside of West and South Hawaii were more likely to be diagnosed with asthma than children elsewhere on the island, she said. In Ka‘u and Kona, 19 percent of children had been medically diagnosed with asthma compared with the rest of the island which ranged between 24 and 27 percent.

“The rate of asthma is not higher in the vog exposed areas, in fact it is lower,” she said. However, she did note that around the nation, the percentage of kids diagnosed with asthma stands around 10 percent.

But, if kids do have asthma and live in South and West Hawaii, they’re more likely to a higher rate of bronchitis. In Kona, a child is three times more likely to cough than in North and East Hawaii, she said. Coughing is often a symptom of asthma.

“Vog is not causing asthma to start in the first place, but if you have asthma it will make it worse,” she said. “This is from 10 years of data to compare.”

Since June 2002, the university has conducted grant-funded studies around the Big Island to determine the impact of vog on health, she said. On Friday, Tam provided an update on the study that assessed nearly 2,000 kids to residents of Pahala during the 15th annual Community Meeting hosted by nonprofit Ka‘u Rural Health Community Association.

Bernadette Longo, an assistant professor at the University of Nevada at Reno also provided an update on some of her studies, which have been going on for nine years. Her studies also indicate no direct correlation between the onset of asthma and vog, but do allude to a connection between vog and episodes and symptoms.

She did find that in the Pahala area, sulfur dioxide levels are lowest between the hours of 10 a.m. and 7 p.m.

“With the usual trade wind conditions, both the gas and particulates are low,” she said. “That’s really good news because you’re not always being exposed to vog — you can get out and exercise and the kids can do their afternoon activities.”

The HICLASS study focuses on the emissions of Kilauea, which has been erupting almost continuously since January 1983, releasing around 1,600 tons of sulfur dioxide per day when relatively quiet and upward of 6,000 tons when most active, Tam said. She hopes to continue the study for several more years if federal grant funding can be secured.

Vog is formed when sulfur dioxide from the volcano reacts with oxygen, sunlight, dust particles and water in the air to form tiny droplets known as sulfate aerosols, sulfuric acid and other substances. It takes approximately six hours for sulfur dioxide to turn into sulfate, she said.

According to the state Department of Health, people with pre-existing respiratory conditions are more prone to be adversely affected by vog, also called volcanic smog. Some symptoms include headaches, sore throats, coughing and wheezing.

Normally, vog is carried southwest by trade winds and eventually is trapped in West Hawaii, she said. However, during the winter months and when trades are absent, the vog lingers in East Hawaii.

That means, she said, that the vog seen in South Hawaii is in most cases composed of sulfur dioxide whereas the vog in Kona has already become sulfate, which is more acidic. There is no data to show whether sulfur dioxide or sulfate is more harmful, Tam said.

However, even with the increased air pollution, the island’s worst air still fares better than 24 urban areas in the country, she said, adding that Hawaii’s vog contains fewer particulates from vehicle and industrial exhaust.

In South Kona, air samples showed the concentration of particulates to be 8 micrograms per cubic meter compared with Union Town, Pa., which notched 18 micrograms per cubic meter, she said. In comparison, China prior to the 2008 Olympics had a concentration of 180 micrograms per cubic meter.

“Compared to those places, our air is relatively clean in terms of particulates,” she said before noting no lead was found in the Hawaii samples as of 2005. “It’s sulfur dioxide. It doesn’t have all the same stuff in it as smog.”

To track vog online, visit http://hiso2index.info and airnow.gov.

Email Chelsea Jensen at cjensen@westhawaiitoday.com.