The acute effects of volcanic ash on pulmonary function in children

ABSTRACT

To evaluate the acute effects of the Mt. Pinatubo volcanic ash on pulmonary function, we studied 103 school children with ages ranging from 12 to 17 years and residing in Metro Manila where about 2.0 cm of ash had fallen. All study participants were involved in a previous study wherein their baseline pulmonary functions were measured. Two weeks after ash exposure, outcome variables measured included respiratory symptoms, forced vital capacity (FVC), forced expiratory volume in one second (FEV1), maximal midexpiratory flow (MMEF), and peak expiratory flow rate (PEFR). Data on composition and particulate size of volcanic ash were obtained. Ashfall exposure produced only transient and tolerable respiratory symptoms, the most common being rhinorrhea, sneezing and cough. Mean fall in FVC was-0.06468+-0.207 liters and-0.0681 +-0.207 liters for FEV1. Males showed a greater decrease in these measurements compared to females. These differences were statistically significant but small and may not be clinically significant. Also, measures of pulmonary function did not correlate with a history of exposure to cigarette smoke nor with the presence of respiratory symptoms. The presence of a demonstrable but minimal adverse effect on pulmonary function may be partly due to precautionary measures taken during the ashfall. It is ideal to repeat pulmonary function tests on the population periodically to document any long-term exposure-related decline in pulmonary function and to validate the present observations against new spirometric measurements at a time of re-exposure and almost nil or absent ashfall exposure. Studies must be done in communities closer to the volcano where these observed changes in pulmonary function may be magnified The widespread destruction caused by the series of eruptions of Mt. Pinatubo in Castillejos, Zambales from May to August, 1991 has raised not only economic concerns but questions on environmental and health aspects as well. With its major eruption on June 15 to 16, 1991, volcanic ash was spawned far with a radius of 850 kilometers from the vent. Typhoon winds prevailing at that time facilitated the spread of volcanic ash to more populated areas as far as Palawan to the south and even as far as Cambodia to the west Analysis of volcanic ash yielded a predominance of respirable particles smaller than 10 micra in diameter and the minerals, silicon dioxide and aluminum oxide. Experience with clinical effects on the respiratory system of volcanic ashfall is rather limited. Recent reports have have dealt mostly on the May 1980 eruption of Mt. St. Helens in Washington, USA, where the composition of volcanic ash was comparable to that spewed by Mt. Pinatubo After eruption of Mt. St. Helens, there was note of an increase in medical consultations for wheezy bronchitis among young children. Questions raised included the possibility of silicosis developing in the exposed population and also on the acute effects of the ash, both in persons with pre-existing lung disease and, as a non-specific irritant, in normal individuals. Johnson, et. al 2 studied the pulmonary function of children residing within a 90 mile radius from the volcano 1 week after the eruption and did not find a significant decrease from normal values. A similar study by Buist et al.,3 on children attending a summer camp situated close to the volcanic site did not show either a within-day or between-day effect on lung function even among children with pre-existing lung diseases In Metro Manila, there were anecdotal reports of increased respiratory symptoms among residents, including school children, after the Mt. Pinatubo eruption caused volcanic ash fall. This study aims to evaluate the acute effects of inhaled volcanic ash on the pulmonary function of school children in Metro Manila Average ashfall in Metro Manila located 180 aerial kilometers from Mt. Pinatubo was 2.0 cm., average ashfall in areas within a 10 kilometer radius from the volcano was 50 cm.