Posted by: Anna Webb | April 24, 2009

Monitoring Vog on the Big Island

The easterly tradewinds that blow onto the East and Southeast side of Hawaii’s Big Island are known as the cleanest air in the world. After traveling over some 2500 miles of Pacific Ocean, it’s clean and fresh when it arrives. Due to the direction in which it travels, it typically blows volcanic emissions toward the southwest and away from the Puna District. Therefore, Puna rarely experiences “bad air”. 

However, every now and then and more often this year than in the past, the wind shifts direction and Puna gets hit with a thick blast of “vog”. Vog is comprised of a variety of toxic chemicals the most common of which is sulfur dioxide. Measured in parts per million (ppm) it can be hazardous in large amounts. With increased emissions from both the Pu’u’O’o vent and the Kilauea crater, it only takes a weakened tradewind to begin to enter this area. And, when the wind shifts to a westerly or north westerly direction, it hits fast. 

Unfortunately, much of the Puna District does not have monitoring devices in place to monitor for unhealthy levels of pollutants.

I recently emailed and received a reply from the EPA regarding their new”Air Now” website. They worked with the Hawaii Department of Health to develop a new site because their original site did not display sulfur dioxide emissions. Monitors can be found at Hilo, Mountain View, Volcanoes National Park, Pahala, Kona, Honolulu and the Puna E Station.

At first glance, it seems like good coverage, but with all of the various microclimates there needs to be more monitors in place. Residents know and understand the various areas, their unique locations, geographic perspectives to the two active vents and subsequent climates.

For example, there can be vog in Pahoa but not on the coast at Kalapana, Kehena, Opihikao or Kapoho. And, vice versa, on the coast but not in Pahoa. And, sometimes it inundates the entire area from Hilo throughout the East side of the Island. Earlier this week, visibility was less than 1/2 mile and the ocean was obscured down on the coast in Lower Puna. 

As I write this, the winds have shifted and gusts are bringing in “vog”. The tell tale symptoms are burning eyes, nose, throat, headaches and rapid pulse.

Strides are being made to develop a comprehensive monitoring system that is user friendly to the public. For this reason, it’s an important time to voice your ideas and thoughts to both the EPA and the Hawaii Department of Health.

You may contact Scott Jackson at the EPA Office of Air Quality Planning and Standards at

To discuss monitor placement, contact Lisa Young at


  1. My son recently went to the ER because of possibly VOG related reasons.

    I can’t stand the stuff, but it sure beats “SMOG”.


%d bloggers like this: