HILO >> An analysis of Environmental Protection Agency air pollution data distributed last week by an online publication concludes that little Hilo has the second-worst air quality in the nation, but in this case the real problem may be with how one defines “Hilo.”

The online publication 27/7 Wall St. declared Hilo’s air quality to be worse than that of Phoenix and Bakersfield, Calif., and only slightly better than California’s Riverside-San Bernardino area, but Hilo has none of the heavy traffic and industry blamed for polluted air in those cities.

But Hawaii island does have an active volcano.

The article by 24/7 Wall St. cited data showing that Hilo’s PM2.5 reading — which is a measurement of particulate matter that is 2.5 micrometers in diameter or smaller — was high for 144 days, while air pollution reached “unhealthy levels” on 99 days. The data was collected in 2018.

Indeed, during last year’s three-month Kilauea Volcano eruption, emissions spiked. Fissure 8 in Leilani Estates in Lower Puna on some days was producing more than 100,000 tons of sulphur dioxide per day, which dramatically affected air quality in Kau and Kona.

Emissions died down almost entirely as the eruption came to an end in August 2018.

The article also seems to confuse Hilo with the island as a whole, since it gives a population count for Hilo of more than 196,000, which amounts to roughly the population of the entire 4,000-square-mile island. Hilo’s population is less than 45,000.