Air Pollution by Hydrothermal Volcanism and HumanPulmonary Function

Linhares, D.,1,2 Garcia, P.,1,3 Viveiros, F.,2,4 Ferreira, T.,2,4 Rodrigues, A.1,2

Volcanism is considered an important natural source of pollutants impacting on environment and health quality. It is estimated that about 10% of the worldwide population lives in the vicinity of an active volcano.Several epidemiological studies have established an association between long-term exposure to anthropogenic air pollution and changes in lung function. Although anthropogenic air pollution is far more studied that the volcanogenic, this last may have a far hazardous potential.The gases released in volcanic areas can have strong impacts in human health. However, there is a lack of studies in the assessment of the chronic health effects of the volcanism.

Background ObjectivesObjectives

To assess the effects of chronic exposure to volcanogenic air

pollution (essentially CO2);

To test the association of respiratory defects in humans with

hydrothermal soil diffuse degassing.

To assess the effects of chronic exposure to volcanogenic air

pollution (essentially CO2);

To test the association of respiratory defects in humans with

hydrothermal soil diffuse degassing.

Methodology

2. CO2 assessment

Assessment of the amounts of CO2 released by soil diffuse degassing were made using a portable instrument that performs measurements based on the accumulation chamber method.

Results Discussion

ConclusionsConclusionsHigher frequencies of pulmonary restrictions and COPD, as well as an exacerbation in COPD severity were observed in Ribeira Quente inhabitants (chronically exposed to volcanogenic soil CO2 diffuse degassing).

These findings contribute to explain the higher incidence rates of chronic bronchitis previously referred for the inhabitants of Furnas Volcano.

Biomonitoring programs and implementation of mitigation measures (e.g. construction of

natural/forced ventilation systems) to minimize the risk of respiratory diseases should be considered.

Figure 1. Location of São Miguel Island. The sites represented in the map are the two studied areas (Ponta Delgada city and

Ribeira Quente village). 

1. Sampling sites

AcknowledgmentsThe authors thank Catarina Silva, Ana Ferreira, Carolina Parelho, Carla Raposo, and Ricardo Camarinho for their support in field and laboratory work. Diana Linhares and Fátima Viveiros were supported, respectively, by Ph.D. and postdoc fellowships from the Fundo Regional da Ciência (Regional Government of the Azores) (PROEMPREGO Programme) (M3.1.2/F/019/2011 and M3.1.7/F/018/2011). Fátima Viveiros is nowadays postoc of the Fundação para a Ciência e Tecnologia. The authors also thank the financial support of BioAir—Biomonitoring Air Pollution: Development of an Integrated System (M2.1.2/F/008/2011) from Fundo Regional da Ciência (Regional Government of the Azores).

Soil CO2 Fluxes

Lung Function

Figure 2. Proportion (%) of individuals with obstructive and restrictive airway diseases in study (Ribeira Quente) and reference (Ponta Delgada) groups.

Binomial Logistic Regression

Number of Observations: 533

Parameter OR (95%CI)a p-value

Exposure to soil CO2

degassing   

Yes (study group) 3.55 (1.55– 8.14) 0.003

No (reference group)

1.00  

aOR, Odds Ratio; 95% CI, 95% Confidence Interval

Ordinal Logistic Regression

Number of Observations: 533

Parameter OR (95%CI)a p-value

Exposure to soil CO2

degassing   

Yes (study group) 3.96 (2.43– 6.46) <0.001

No (reference group) 1.00  aOR, Odds Ratio; 95% CI, 95% Confidence Interval

Table 2. Adjusted association between study participants, exposure to soil CO2 diffuse degassing and pulmonary restriction.

Table 3. Adjusted association between study participants, exposure to soil CO2 diffuse degassing and COPD.

Figure 3. Soil diffuse degassing in Ribeira Quente village (adapted from Viveiros et al. 2010). The dots represent the participants and outcome of respiratory status (Green- normal; Yellow- restriction; Red – COPD).

Site Households CO2 Flux

Ponta Delgada 0% in DDS areas 15,4 g/m2/d

Ribeira Quente 98% in DDS areas 508,8 g/m2/d

Increase in 33 times the average CO2

flux

Integrated system

•· The measurements of soil CO2 flux demonstrate that the study group must be chronically exposed to much higher concentrations of CO2 than the reference group (Fig 2);

· The higher frequency of restrictions and obstructions in individuals inhabiting Ribeira Quente suggests an association between these respiratory diseases and the chronic exposure to elevated soil CO2 diffuse degassing activity (Fig. 3);

· The risk of having a restrictive airway disease was 3.6-fold higher for the inhabitants of Ribeira Quente when compared to the reference group. Similarly, the risk of COPD exacerbation was 3.7-fold higher in Ribeira Quente inhabitants (Table 1 and 2).  

  

Table1. Percentage of houses built in DDS (difusse degassing soils) areas and CO2 flux averages.

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1Department of Biology, University of the Azores, Ponta Delgada, 9501-801 Azores, Portugal2CVARG, Center for Volcanology and Geological Risks Assessment, University of the Azores, Ponta Delgada, 9501-801 Azores, Portugal3CE3C, Centre for Ecology, Evolution and Environmental Changes and Azorean Biodiversity Group, University of the Azores, 9501-801 Ponta Delgada, Portugal4Department of Geosciences, University of the Azores, Ponta Delgada, 9501-801 Azores, Portugal