THE EFFECTS OF EXPOSURE TO AIR PARTICLE POLLUTION: Evidence from volcanic activity in Hawaii

Daily exposure to air particle pollution increases emergency room (ER) admissions for lung-related health issues, according to new research by Timothy J. Halliday, John Lynham and Áureo de Paula, published in the May 2019 issue of The Economic Journal.

Their study considers the impact of volcanic emissions in Hawaii and suggests that an above average increase of particles in the air raises the number of ER admissions by up to 35%, with the very young being most affected.

The research has implications for understanding the optimal level of air pollution under the National Ambient Air Quality Standards (NAAQS) in the United States. The study finds evidence of harm at particle levels below those set out in the NAAQS.

The study looks at emissions from the Kilauea volcano between 2000 and 2012, measuring air quality from various monitoring stations across the state and comparing them to administrative data on ER admissions due to pulmonary-related reasons.

The researchers focus on variations in particulate pollution on the island of Oahu, northwest of the island of Hawaii, which is affected by the volcano’s emissions. They find that there is strong evidence that daily exposure to such pollution increases admissions to ER for lung-related health issues.

The study also estimates that an above average increase (one standard deviation increase) in particulates on Oahu increases ER admissions by 25-35%. These effects are mostly concentrated among the very young.

Kilauea is the largest stationary source of sulphur dioxide pollution in the United States. This reacts with sunlight, oxygen, dust and water in the air to product volcanic smog – or ‘vog’ – which is one example of particulate pollution.

Typically, the Hawaiian Islands have some of the best air quality in the world, but whenever Kilauea starts emitting gases and trade winds are low, the state’s residents experience short-term exposure to elevated levels of particulates.

This presents the authors with a ‘natural experiment’, where the public has been randomly exposed to pollution in a way that mimics an actual experiment, to understand the cost of one pollutant.

Such studies in the past have been hampered because most sources of pollution emit many pollutants at once. In fact, many studies that look at the effect of particulates alongside other pollutants find that they have no impact on health outcomes.

According to the authors, this helps to address the challenges in understanding what the optimal level of air pollution should be to set the NAAQS. They provide evidence of harm due to particulate pollution below the NAAQS set levels.

'Vog: Using Volcanic Eruptions to Estimate the Health Costs of Particulates' by Timothy J. Halliday, John Lynham and Áureo de Paula published in the May 2019 issue of The Economic Journal

Timothy J. Halliday

Associate Professor of Economics and the Chair of the Department of Economics at University of Hawaii at Manoa

John Lynham

Professor of Economics at University of Hawaii

Áureo de Paula

Professor of Economics at University College London