Maui received an "A" grade for air quality - the best in the state - in an American Lung Association national report that may raise the eyebrows of residents who have complaints about cane burning and dust from fallow fields.
In the "State of the Air 2013" report released last week, Honolulu received a "B" while Hawaii County received an "F" in the particle pollution 24-hour category. Figures for Kauai were incomplete.
Steve Businger, a member of the American Lung Association in Hawaii's Leadership Council, attributed the Big Island's failing grade to air quality monitors that are downwind of the active volcano at Kilauea.
Even as some Maui residents complain about cane burning and dust from various fallow agricultural fields, the American Lung Association’s recently released “State of the Air 2013” report gave Maui an “A” grade for its air quality in the particle pollution 24-hour category.
The Maui News file photo
On Maui, Businger explained that national air quality standards are based on 24-hour averages and that cane burning and agricultural dust problems do not occur for long enough periods to affect the averages.
The University of Hawaii meteorology professor added that Maui residents do not live next door to coal-fired plants that drive up air pollution rates in large industrial cities.
The report assessed counties and cities based on their scores for ozone (done only on Oahu for Hawaii, in which Oahu received an "A" grade) and year-round and short-term particle pollution levels.
According to the U.S. Environmental Protection Agency's National Ambient Air Quality Standards, particulate matter, or PM 2.5, measured in smoke and dust conditions should not average more than 35 micrograms per cubic meter in a 24-hour period.
Particle pollution is a mix of very tiny solid and liquid particles in the air. If they're small enough, they can stay in the air for long periods, Businger said.
Lisa Young of the state Department of Health's Clean Air Branch on Oahu said that while at times particulate matter measured at air quality stations may hit high levels for an hour, the pollution does not usually last for a 24-hour period due to changing of the wind or other factors.
She said that there are no standards for particulate matter for one hour.
The state has two air quality monitoring stations on Maui, one in Kihei and the other recently put back on line in Paia.
Young said some residents have complained that the longtime Kihei monitoring station is in the wrong place. She countered that the station is in the most logical location because most of the island's air pollution naturally flows down to South Maui. It also is in a place that is dry and dusty, so it would have the best chance of picking up particle pollution.
For the month of April, Young said, readings at the Kihei station ranged from a low of 5 micrograms per cubic meter to a high of 12 micrograms per cubic meter, meaning that the averages over a 24-hour period were not close to exceeding national standards.
In the report, Hawaii County received a failing grade despite nearly halving the number of days with unhealthy particle pollution - from 23.5 days in 2012 to 12.5 this year.
Honolulu is the only county in the state that collected data on ozone levels. There were no days of unhealthy levels of ozone, or smog, which is the most widespread air pollutant.
Volcanic gas emissions from the Big Island's Kilauea volcano create vog. If the trade winds stop or if wind blows Kona or southerly, other islands including Oahu, Maui and Kauai receive vog. Kilauea has been in constant eruption since Jan. 3, 1983.
Still, people should be assured that Hawaii's overall air quality is good, Businger said.
"I don't think people need to worry unless they happen to be very sensitive to vog," Businger said. He added that on days when vog levels are high, people should try to stay indoors, limit outdoor exercise and drink plenty of fluids.
The annual report grades counties nationwide for ozone and particulate pollution levels. Cheyenne, Wyo., ranked No. 1 as the cleanest city for year-round particle pollution. Bakersfield-Delano in California ranked the worst for particle pollution, while California's Los Angeles-Long Beach-Riverside region had the worst ozone ranking.
* The Associated Press contributed to this report. Melissa Tanji can be reached at email@example.com.