By Jan TenBruggencate
Advertiser Columnist

An interesting sidelight to the two-decadelong eruption of Kilauea Volcano is that people have gotten so used to its effects that they miss them when they're gone.

An O'ahu resident (an editor at the Advertiser) whose entire residence in the Islands has been within the life of this eruption called a little more than a week ago to ask: "There's kona winds. How come there's no vog?"

The reference is to the acrid smoke that comes both from the vent at the eruption site and from the caustic steam that rises when the lava hits the ocean. The stuff gets into the air, and during southeasterly winds, blows from the Big Island up across the rest of the state.

With the vog comes limited visibility — a pale mist interrupting the deep greens of our mountainsides. With it, too, come itchy eyes and runny noses for many residents. It's tough on folks statewide during southeast winds, but there are areas of the Big Island where vog is a daily occurrence.

Back on Sept. 26, the winds were from the southeast — what some folks call kona weather, although the Kona visitor industry isn't thrilled about that terminology. But O'ahu wasn't all vogged up.

I made some calls.

"Nothing unusual here," said Don Swanson, the geologist who runs the Hawaiian Volcano Observatory. "I don't know why you wouldn't be getting it. The same amount of lava and gas are coming out."

He suggested that perhaps heavy rains could have washed the vog out of the air.

I checked with National Weather Service meteorologist Hans Rosendal.

"Vog comes up more with southeast winds, and right now, most places do have winds slightly south of east," he said.

Rosendal said there was actually some haze in parts of O'ahu, but it didn't come from the volcano.

"A lot of the 'vog' on O'ahu is actually from local fires and pollution from car exhausts," he said.

His suggestion — and he had the benefit of actually viewing the vog plume on satellite pictures — was that this particular day's vog was kind of patchy, and O'ahu happened to be in a low-vog zone. Indeed, farther to the northwest, Kaua'i had a dense vog blanket.

The message for folks paying attention to vog is that Kilauea still has lots of it. The volcano produces some 1,500 tons of mainly sulfur dioxide daily, said volcano observatory gas geochemist Jeff Sutton, which quickly reacts in the presence of sun, water and oxygen to form the vog we breathe.

Vog is made up of a mixture of gas and particles — mainly bits of volcanic dust, sulfur dioxide and sulfuric acid, Sutton said.

"Kilauea produces more of this pollutant than the dirtiest power plant on the Mainland," he said.

Jan TenBruggencate is The Advertiser's Kaua'i bureau chief and its science and environment writer. Reach him at (808) 245-3074 or jant@honoluluadvertiser.com.