Hawaii conjures the postcard perfect image of health in most people’s minds: sunshine, warmth, gentle breezes, inviting water, lush green plants and tropical flowers. All true. So newcomers and visitors to the islands may be surprised to learn Hawaii harbors a serious health hazard in the form of air pollution from the actively erupting volcano on the Big Island.

Health Hazard

All that gas and smoke emitted by Kilauea volcano make for intensely red sunsets and great photos, but it also endangers health. Volcanic smog, or Vog, poses danger to humans, other animals and plants, according to the US Geological Survey‘s fact sheet on Vog:

Noxious sulfur dioxide gas and other pollutants emitted from Kilauea Volcano on the Island of Hawai`i react with oxygen and atmospheric moisture to produce volcanic smog (vog) and acid rain. Vog poses a health hazard by aggravating preexisting respiratory ailments, and acid rain damages crops and can leach lead into household water supplies. The U.S. Geological Survey’s Hawaiian Volcano Observatory is closely monitoring gas emissions from Kilauea and working with health professionals and local officials to better understand volcanic air pollution and to enhance public awareness of this hazard.

How it Works

Simply put, vog is a mixture of chemicals suspended in the air. Sulfur dioxide (SO2) gas and other pollutants emitted from Kilauea Volcano interact chemically with atmospheric moisture, oxygen, dust, and sunlight to produce volcanic smog (vog) and acid rain. Vog appears as a visible haze consisting of gas plus a suspended mixture of tiny liquid and solid particles, called aerosol. It is this haze that makes the Kona sunsets famously red. According to the USGS fact sheet on vog:

SO₂ is a poisonous gas that irritates skin and the tissues and mucous membranes of the eyes, nose, and throat. During even moderate physical activity, SO₂ penetrates deeply into the airway and can produce respiratory distress in some individuals. In the absence of strong winds, SO₂ emitted by Kilauea can accumulate in the air and reach levels that exceed Federal health standards. Since 1986, this has occurred more than 85 times within Hawai`i Volcanoes National Park, which includes much of Kilauea.

Ill Effects

Because vog particles are small, they easily lodges deep in human lung cells where they are readily retained, aggravating preexisting respiratory ailments and may induce asthma attacks. About 106,000 people in Hawaii are affected by asthma, and approximately one third are children, according the Hawaii State Department of Health. Vog is an important trigger of asthma attacks, along with cane burning, secondhand smoke and pet dander.

Vog exposure also causes more generalized symptoms, including:  headaches, breathing difficulties, increased susceptibility to respiratory ailments, watery eyes, sore throat, flu-like symptoms, and a general lack of energy.

Vog also interferes with plants ability to breathe, causing crop failures in everything from flowers to coffee. Since 1983, Pu’u O’o vent of Kilauea Volcano has spewed roughly 2,000 tons of sulfur dioxide per day, according to USGS. In March 2008 when Halema’uma’u vent opened, the amount of sulfur dioxide doubled. On November 24, 2009, the US Department of Agriculture declared there were major crop failures on Kona and the US Government declared the BIg Island “a primary natural disaster area” because of losses caused by volcanic emissions since the start of the year. It continues an expired disaster designation for the island that was originally issued in July 2008. The disaster designation was made Nov. 24, making all qualified farm operators on the island eligible for low-interest emergency loans from the Farm Service Agency, according to a Hawaii Tribune-Herald report.

The related acid rain can leach lead from rainwater catchment systems into household water supplies, leading to lead poisoning and mental health problems. When it’s really thick, volcanic haze reduces driving visibility, causing motor vehicle accidents. The irony is that Vog is all natural.

How to Spot Vog

On neighboring islands, such as Maui and Molokai, residents and visitors don’t typically notice vog unless the prevailing northeast Trade Winds slow, stop or reverse pattern. When the winds blow from the southwest, locals call these “Kona winds”, because the winds blow vog from the Big Island over the state, creating those famously red Kona sunsets on other islands. Thus, an unusually deep red sunset is almost a sure sign that volcanic air pollution is present. Sudden and unexplained headaches, scratchy throat and lethargy are common symptoms of vog exposure. Health officials usually recommend staying indoors on voggy days and avoiding any strenuous activity outside.

Common Signs of Vog

1. Hazy skies accompanied by slow or eratic Trades or reversed wind patterns
2. Smell of smoke in the air
3. Deep red sunset
4. Sudden headache, scratchy throat, lethargy or difficulty breathing