Question: Why hasn't there been any information or warning given about the vog? Last week on Oahu, it was so thick and heavy, I was wondering what I was breathing in. Also, I found ashy material on my car. Shouldn't we be concerned?

Answer: The effects of volcanic emissions destroying crops and other plants on the Big Island have been documented, but health officials acknowledge the long-term health effects of exposure to vog are not known.

For now, if you are not on the Big Island and if you are not prone to respiratory problems, the state Department of Health says there is not much of a health threat from the vog that seems to frequently blanket Oahu these days.

Furthermore, it says the “;ashy”; material you saw on your car was not spewed from Kilauea volcano.

Neither volcanic ash nor sulfur dioxide travels from the Big Island to other islands, said Health Department spokeswoman Janice Okubo.

“;The vog that people on islands other than (the Big Island) see is particulate matter (dust, soot and other tiny bits of matter),”; Okubo said.

According to a state Web site on vog - http://hawaii.gov/ gov/vog - “;The distance from the Kilauea volcano is too great for SO2 (sulfur dioxide) to travel across the ocean in high enough concentrations to create health risks for people on islands other than Hawaii (Island).”;

The amount of vog in the air depends on the amount of emissions from Kilauea volcano, wind conditions and weather.

While the general public outside of the Big Island shouldn't be adversely affected, “;individuals with underlying respiratory conditions, such as asthma and emphysema, may experience discomfort or health effects from vog and should take precautions,”; Okubo said.

It's a different matter for people living on the Big Island.

The Hawaii County Civil Defense regularly sends out alerts about vog conditions, and the Health Department has worked with the county on letting residents there know how dangerous vog conditions are and what they should do.

Warnings to Big Island communities are issued when elevated levels of pollutants in the air exceed federal standards.

In July, the state convened an interagency task force in Hilo to address the hazards of volcanic emissions and to develop strategies to mitigate the effects on public health and agriculture.

In a news release, the state said that since March 12, “;sulfur dioxide emissions from a new gas vent in Halemaumau Crater have affected residents with respiratory problems, caused voluntary evacuations, and caused significant damage to agricultural farms and ranches. The emissions have also caused concern for the long-term effects on health, water quality and agriculture.”;

In addition to the Web site, you can get up-to-date information on vog and volcanic emissions from the Health Department's Hawaii Volcano Helpline. Call, toll-free, (866) 767-5044.

The Helpline is staffed from 5 a.m. to 5 p.m. weekdays and from 9 a.m. to 5:30 p.m. weekends, while recorded messages, updated daily, are accessible 24 hours a day, seven days a week.