The state Department of Health is slightly revising its sulfur dioxide air quality ratings system to take into account a new standard adopted by the U.S. Environmental Protection Agency.

The green, or "good," and yellow, or "moderate," sulfur dioxide ratings in the state’s color-coded air quality condition guide are due to be altered slightly. But environmental health specialist Lisa Young says most members of the public won’t notice.

The state adopted the ratings system after Kilauea began spewing sulfur dioxide from Halemaumau Crater at the volcano summit.

The EPA issued a standard last year that lowered the acceptable level of sulfur dioxide in the air to 75 parts per billion measured hourly. The previous standard allowed 140 parts per billion averaged over 24 hours.

The new advisory levels can be found online at www.hiso2index.info.

At the website, the public can obtain current information on sulfur dioxide levels on the Big Island, the Department of Health said.

Sulfur dioxide is an irritant gas emitted by Kilauea. People with asthma who are physically active outdoors are most likely to experience the health effects of sulfur dioxide.

The revised Hawaii advisory levels of sulfur dioxide are aligned with the new national standard, said Gary Gill, deputy director for environmental health. "We still caution the public to rely on how they personally respond to SO2 in the air and not just on the DOH air monitors to make decisions," he said.