[Effects of volcanic sulfur dioxide on reconstruction workers and residents returning to Miyake Island]

Acute effects of air pollution on peak expiratory flow rates and symptoms among asthmatic patients in Chiang Mai, Thailand

The open burnings and forest fires have been recognized as the major sources of severe air pollution in the upper north of Thailand; however, there have been no clear evidences to show the associations between the air pollution and health effects in the area. We assessed the effects of air pollutants on the peak expiratory flow rates (PEFR) and symptoms in asthmatics. A cohort of 121 asthmatics was followed daily, for 306 days, for their PEFR and asthma symptoms. The daily air pollutants, including particulate matter with aerodynamic diameter <2.5 μm, particulate matter with aerodynamic diameter <10 μm (PM(10)), carbon monoxide, ozone, nitrogen dioxide (NO(2)), and sulfur dioxide (SO(2)), and the meteorological parameters, including pressure, temperature, relative humidity, rain quantity, and sunshine duration, were monitored. The PEFRs were fitted with general linear mixed models. The asthma symptoms were analyzed with the generalized estimating equations. There were positive associations of NO(2) with morning PEFR, with a coefficient of 0.06 [95% confidence interval (CI), 0.00-0.12]; of SO(2) with evening PEFR [with a range of coefficients of 0.88-1.00 (95% CI, 0.31-1.54)] and daily average PEFR [with a coefficient of 0.47 (95% CI, 0.00-0.94)]; of PM(10) with evening PEFR, with a coefficient of 0.02 (95% CI, 0.00-0.04). There was also negative association of PM(10) with ΔPEFR, with a coefficient of -0.01 (95% CI, -0.01 to -0.00). No pollutants were related to asthma symptoms. More studies are needed, particularly at low dose in adult asthmatics, to validate our findings.

Air pollution-related peak expiratory flow rates among asthmatic children in Chiang Mai, Thailand

The severity of air pollution in northern Thailand has long been recognized; in spite of that there have been no epidemiological studies regarding the associations between the air pollution and health effects in the area. The authors followed a cohort of 31 asthmatic children (4-11 years of age) residing in Muang district, Chiang Mai, Thailand, from 29 August 2005 to 30 June 2006, for 306 days. The daily air pollutants, including particulate matter with aerodynamic diameter < 2.5 microm, particulate matter with aerodynamic diameter < 10 microm, carbon monoxide, ozone (O(3)), nitrogen dioxide, and sulfur dioxide (SO(2)), and the meteorological parameters, including pressure, temperature, relative humidity, rain quantity, and sunshine duration, were recorded. The peak expiratory flow rates (PEFRs) were fitted with pollutants and meteorological covariates using general linear mixed models to account for random effects and autocorrelation. The authors found that there were inverse associations of SO(2) and evening PEFR, with a coefficient of -2.12 (95% confidence interval (CI) = -3.22 to -0.28); of SO(2) and daily percent deviation of PEFR, with a coefficient of -0.73 (95% CI = -1.33 to -0.12); and of O(3) combining with SO(2) and daily average PEFR, with a coefficient of -0.16 (95% CI = -0.31 to -0.00) and -1.60 (95% CI = -3.10 to -0.11), respectively. The associations of O(3) and SO(2) with PEFR were found even when SO(2) concentrations never exceeded the standard level.

Effects of SO2 on respiratory system of adult Miyakejima resident 2 years after returning to the island

BACKGROUND

Mt. Oyama in Miyakejima Island erupted in June, 2000. All Miyake villagers were forced to evacuate from the island in September, 2000, due to continuous eruptions and emissions of unsafe amounts of volcanic gas, mainly SO2. From February, 2005, Miyake villagers returned to the island despite volcanic gas still being emitted.

OBJECTIVES

This study examines the 2-yr changes in Miyake residents' respiratory systems from autumn 2004 to November 2006.

METHODS

The study population was 823 Miyake adult residents who participated in the health check-up in 2006. Respiratory effects were evaluated by a questionnaire for respiratory symptoms and spirometry. SO2 has been continuously monitored at 7 sampling points of the inhabited area. The mean SO2 concentration from February 2005 to November 2006 was 0.031 ppm. The area was categorized into 4 areas by SO2 concentration, namely, areas L, H-1, H-2 and H-3, where average SO2 concentrations were 0.019, 0.026, 0.032, and 0.045 ppm, respectively.

RESULTS

The study subjects showed no deterioration in lung function. Prevalence of cough and phlegm among all participants were significantly higher in 2006 than in 2004, and age-, sex- and smoking-adjusted odds ratios of cough and phlegm were 1.75 (95%CI 1.33-2.30) and 1.44 (1.12-1.87). Prevalence of chronic bronchitis-like symptoms among normosusceptive subjects in 2006 was 4.1% which was significantly higher than that of 2.1% in 2004 (p=0.035). Compared to area L, the frequencies of phlegm and irritation of the nose were significantly increased in areas H-2 and H-3.

CONCLUSION

SO2 exposure-related respiratory symptoms were observed in adult Miyakejima residents after returning to the island.

Cardiorespiratory health effects associated with sulphurous volcanic air pollution

OBJECTIVE

To investigate cardiorespiratory health effects associated with chronic exposure to volcanogenic sulphur dioxide (SO2) and fine sulphate particle (< or = 0.3 microm) air pollution emitted from Kilauea Volcano, Hawaii.

STUDY DESIGN

Environmental-epidemiological cross-sectional study.

METHODS

An air study was conducted to measure exposure levels in the downwind area, and to confirm non-exposure in a reference area. Cross-sectional health data were collected from 335 adults, > or = 20 years of age, who had resided for > or = 7 years in the study areas. Prevalence was estimated for cardiorespiratory signs, and self-reported symptoms and diseases. Logistic regression analysis estimated effect measures between exposed and unexposed groups considering potential confounding including age, gender, race, smoking, dust and body mass index (BMI). Student's t-tests compared mean differences in blood pressure (BP), pulse and respiratory rates.

RESULTS

There were statistically significant positive associations between chronic exposure and increased prevalence of cough, phlegm, rhinorrhoea, sore/dry throat, sinus congestion, wheezing, eye irritation and bronchitis. The magnitude of the associations differed according to SO2 and fine sulphate particulate exposure. Group analyses found no differences in pulse rate or BP; however, significantly faster mean pulse rates were detected in exposed non-medicated, non-smoking participants with BMI <25, and in participants aged > or = 65 years. Higher mean systolic BP was found in exposed participants with BMI <25.

CONCLUSIONS

Long-term residency in active degassing volcanic areas may have an adverse effect on cardiorespiratory health in adults. Further study at Kilauea is recommended, and the authors encourage investigations in communities near active volcanoes worldwide. Public health interventions of community education, and smoking prevention and cessation are suggested.