As Mauna Loa erupted in late November 2022 for the first time since 1984, the emissions produced vog or volcanic smog. Vog—a mixture of ash, sulfur dioxide and other gasses—may cause breathing difficulties, headaches, a sore throat, watery eyes and more to those living near and/or downwind of the vog plume. According to a new study by a team of experts from the Department of Economics at the University of Hawaiʻi at Mānoa, the UH Economic Research Organization (UHERO) and University College London, vog is estimated to have detrimental impacts on student test scores.
These effects are especially pronounced for the poorest pupils who experience impacts that are greater than those for more advantaged pupils. In addition, these effects are greatest in areas with higher baseline levels of pollution such as south Hawaiʻi Island. A key takeaway of the study is that poor air quality can compromise learning outcomes for disadvantaged students and therefore exacerbate economic inequality. Recent work by UH economists Timothy Halliday and John Lynham have also demonstrated that vog causes a large increase in ER visits due to respiratory reasons.
The authors utilized the census of test scores from Hawaiʻi public school students on the Smarter Balanced Assessment (SBA)—a mandatory annual test of math and English literacy skills created to measure college and career readiness for Department of Education students in grades 3 through 8 and 11—from 2015–2018, provided by Hawaiʻi P-20. Within the sample, about half of the students were considered economically disadvantaged and roughly 6% received English language services. In addition, 24% of students identified as Native Hawaiian, 24% Filipino, 18% White, 16% Asian (non-Filipino), 9% Pacific Islander and 8% another ethnicity. In total, the sample consisted of more than 150,000 unique individuals across 260 schools.
Their air quality data was provided by the State of Hawaiʻi Department of Health (DOH). The authors looked at particulates (specifically PM2.5, which are fine inhalable particles with diameters that are generally 2.5 micrometers and smaller) and sulfur dioxide (toxic gas released naturally by volcanic activity) to measure pollution levels. The DOH data on particulate levels was collected through their pollution monitoring stations, which span across numerous locations throughout the state.
Using wind variation and pollution measurements from the DOH monitoring stations, the authors predicted levels of the particulates and sulfur dioxide at a given school using techniques from the geosciences. The researchers then used these predicted measures of air particulates and the SBA scores, to estimate the effect of particulate pollution on test scores.
The authors discovered that an increase in particulates would lead to a small decrease in student test scores. In addition, the effects are estimated to be substantially larger for students who attend schools with poorer average air quality. Specifically, students at schools with an average of 9 micrograms per cubic meter of PM2.5 or higher, which a majority are located in the south/southwest region of Hawaiʻi Island, would experience roughly seven times the decline in test scores than those with less than 9 micrograms per cubic meter of PM2.5. This equates to a reduction of more than 1% in test scores for every standard deviation increase (standard deviation for the sample is equal to 1.84 micrograms per cubic meter) in PM2.5. Therefore, an increase of 1.84 micrograms per cubic meter of PM2.5 led to more than a 1% reduction in test scores.
The average PM2.5 rate from the Ocean View monitoring station between 2015–2018 was 12.64 micrograms per cubic meter of PM2.5—the highest of any Hawaiʻi monitoring station in that period. The highest daily average from that same station between the same time frame came on June 4, 2018 at 55.5 micrograms per cubic meter of PM2.5. According to the authors’ estimates, if schools with higher baseline levels of pollution (in this case, 9 micrograms per cubic meter or greater) saw an increase in PM2.5 from 12.64 to 55.5 micrograms per cubic meter, test scores would fall by more than 25%.
This effect is evident when also focusing on the south/southwest region of Hawaiʻi Island—which is home to summit and rift zones where Kīlauea and Mauna Loa’s vents have been repeatedly active—and has much higher average levels of pollution compared to the rest of the state. In this area, the effect of increases in PM2.5 on student performance is estimated to be roughly five times greater than estimates for the total sample.
Model shows disadvantaged students could be worse
Importantly, the authors show that the impacts of poor air quality fall more heavily on poor pupils as defined by those who qualify for federal programs such as free and reduced lunch. The effects of PM2.5 are larger by a factor of ten and the effects of sulfur dioxide are larger by a factor of six. The authors demonstrated that the disparate effects of pollution by socioeconomic class occur within schools. Hence, these effects cannot be attributed to poorer schools being located in more polluted areas.
“This finding has great implications for environmental justice,” a blog written by co-lead author Rachel Inafuku said. “Students who are more financially stable face less obstacles in accumulating human capital when air quality is poor, suggesting that pollution contributes to the inequality gaps that we observe here in Hawaiʻi and in the U.S.”
Inafuku continued, “The Hawaiian Islands are particularly advantageous for studying the effects of pollution for several reasons. First, Hawaiʻi is home to pristine baseline levels of air quality with average pollutant levels well below EPA ambient air quality standards. Most studies have focused on areas with extremely high average pollution levels and are much less comparable to most areas within the U.S. Furthermore, the level of pollutants throughout Hawaiʻi is truly unpredictable and random. Because the bulk of pollution throughout the state is dependent on emissions from Kīlauea volcano and wind direction, air pollution is based largely on the forces of nature and not man made sources (e.g., traffic, industrial facilities, etc).”
The Department of Economics and UHERO are housed in UH Mānoa’s College of Social Sciences.
The working paper can be found here.