Volcano case studies
Either: Nyiragongo, Democratic Republic of Congo - Poor Country or Montserrat, Caribbean - Poor Country
Either: Mount St. Helens, USA - Rich Country or Iceland - Rich Country
Primary effects: the immediate effects of the eruption, caused directly by it
Secondary effects: the after-effects that occur as an indirect effect of the eruption on a longer timescale
Immediate responses: how people react as the disaster happens and in the immediate aftermath
Long-term responses: later reactions that occur in the weeks, months and years after the event
On 17th January 2002 Nyiragongo volcano in the Democratic Republic of Congo (DRC) was disturbed by the movement of plates along the East African Rift Valley. This led to lava spilling southwards in three streams.
The primary effects - The speed of the lava reached 60kph which is especially fast. The lava flowed across the runway at Goma airport and through the town splitting it in half. The lava destroyed many homes as well as roads and water pipes, set off explosions in fuel stores and powerplants and killed 45 people
The secondary effects - Half a million people fled from Goma into neighbouring Rwanda to escape the lava. They spent the nights sleeping on the streets of Gisenyi. Here, there was no shelter, electricity or clean water as the area could not cope with the influx. Diseases such as cholera were a real risk. People were frightened of going back. However, looting was a problem in Goma and many residents returned within a week in hope of receiving aid.
Responses - In the aftermath of the eruption, water had to be supplied in tankers. Aid agencies, including Christian Aid and Oxfam, were involved in the distribution of food, medicine and blankets.
Montserrat - Poor country case study
Mount St Helens - Rich country case study
Effects - An earthquake caused the biggest landslide ever recorded and the sideways blast of pulverised rock, glacier ice and ash wiped out all living things up to 27km north of the volcano. Trees were uprooted and 57 people died.
Immediate responses - helicopters were mobilised to search and rescue those in the vicinity of the catastrophic blast. Rescuing survivors was a priority, followed by emergency treatment in nearby towns. Air conditioning systems were cleaned after by clogged with ash and blocked roads were cleared. Two million masks were ordered to protect peoples lungs.
Long-term responses - Buildings and bridges were rebuilt. Drains had to be cleared to prevent flooding. The forest which was damaged had to be replanted by the forest service. Roads were rebuilt to allow tourists to visit. Mount St. Helens is now a major tourist attraction with many visitor centres.
Iceland - Rich country case study
Iceland lies on the Mid-Atlantic Ridge, a constructive plate margin separating the Eurasian plate from the North American plate. As the plates move apart magma rises to the surface to form several active volcanoes located in a belt running roughly SW-NE through the centre of Iceland. Eyjafjallajokull (1,666m high) is located beneath an ice cap in southern Iceland 125km south east of the capital Reykjavik
In March 2010, magma broke through the crust beneath Eyjafjallajokull glacier. This was the start of two months of dramatic and powerful eruptions that would have an impact on people across the globe. The eruptions in March were mostly lava eruptions. Whilst they were spectacular and fiery they represented very little threat to local communities,
However, on 14th April a new phase began which was much more explosive. Over a period of several days in mid-April violent eruptions belched huge quantities of ash in the atmosphere.
Local impacts and responses:
The heavier particles of ash (such as black gritty sand) fell to the ground close to the volcano, forcing hundreds of people to be evacuated (immediate response) from their farms and villages. As day turned to night, rescuers wore face masks to prevent them choking on the dense cloud of ash. These ash falls, which coated agricultural land with a thick layer of ash, were the main primary effects of the eruption.
One of the most damaging secondary effects of the eruption was flooding. As the eruption occurred beneath a glacier, a huge amount of meltwater was produced. Vast torrents of water flowed out from under the ice. Sections of embankment that supported the main highway in Southern Iceland were deliberately breached by the authorities to allow floodwaters to pass through to the sea. This action successfully prevented expensive bridges being destroyed. After the eruption, bulldozers were quickly able to rebuild the embankments and within a few weeks the highway was reconstructed.
800 people evacuated
Homes and roads were damaged and services (electricity & water) disrupted
Local flood defences had to be constructed
Crops were damaged by heavy falls of ash
Local water supplies were contaminated with fluoride from the ash
Drop in tourist numbers - affected Iceland's economy as well as local people's jobs and incomes
Road transport was disrupted as roads were washed away by floods
Agricultural production was affected as crops were smothered by a thick layer of ash
Reconstruction of roads and services was expensive
Over 8 days - some 100,000 flights were cancelled
10 million air passengers affected
Losses estimated to be £80 million
Industrial production halted due to a lack of raw materials
Fresh food could not be imported
Sporting events such as the Japanese Motorcycle grand prix, Rugby leagues challenge cup and the Boston Marathon were affected
International impacts and responses:
The eruption of Eyjafjallajokull became an international event in mid-April 2010 as the cloud of fine ash spread south-eastwards toward the rest of Europe. Concerned about the possible harmful effects of ash on aeroplane jet engines, large sections of European airspace closed down. Passenger and freight traffic throughout much of Europe ground to a halt.
The knock-on effects were extensive and were felt across the world. Business people and tourists were stranded unable to travel in to or out of Western Europe. Industrial production was affected as raw materials could be flown in and products could not be exported by air. As far away as Kenya, farm workers lost their jobs or suffered pay cuts as fresh produce such as flowers and bean perished, unable to be flown to European supermarkets. The airline companies and airport operators lost huge amounts of money.
Some people felt that the closures were an over-reaction and that aeroplanes could fly safely through low concentrations of ash. However, a scientific review conducted after the eruption concluded that under the circumstances it had been right to close the airspace. Further research will be carried out as a long-term response to find better ways of monitoring ash concentrations and improving forecast methods.
On 14 April 2010, an explosive summit crater eruption began in Eyjafjallajökull (Eyjafjalla Glacier), a volcano that is situated in south Iceland (figure 1). In the early phases of the eruption, fine-grained ash was ejected up to 10 km into the atmosphere, disturbing air traffic in Europe for days. In Iceland, the rural regions south and south-east of the volcano were heavily exposed to falling ash. The volcano ejected some 250 million tons of ash, of which 8 million tons of particles were 2.8–28 μm in diameter.1–5 Particles with a diameter of <10 μm are inhalable and can compromise respiratory health. Despite the falling ash that changed day to night, many inhabitants, mostly farmers, remained in the area to work on their farms and tend their livestock.
Map of the study area, which reached from just west of Eyjafjallajökull to Vík in the east. The shading illustrates duration and intensity of the ash plume. The darkest areas represent an estimated ash deposition of >500 g/m2, and around Vík, the deposition is estimated around 200 g/m2.
Apart from the immediate life-threatening hazards following a volcano eruption, such as pyroclastic flows, mudslides and glacial outburst floods, several other health risks are associated with living close to an active volcano.6 Short-term exposure to volcanic gases can trigger asthma attacks and has been associated with respiratory morbidity and mortality and increased irritation of the respiratory tract.7 Exposures for longer time periods to volcanic ash and gases have been associated with increases in cardiovascular symptoms8 and increased rates of chronic bronchitis and other respiratory symptoms,910 also in children.11 Symptoms of skin and eye irritation have also been reported.12 The chemical and physical properties of volcanic ash vary a great deal between eruptions and volcanoes, making it difficult to generalise about the toxicity of ash from individual eruptions.12
Volcanic eruptions are violent natural disasters that impose a threat to health as well as to livestock and property. During eruptions, the population may have to be evacuated, depending on risk assessment, and uncertainty and stress experienced during the eruption can influence mental well-being.1314 The aims of this study were to examine medically the most exposed population and to evaluate possible acute physical and mental health effects associated with the Eyjafjallajökull eruption. In addition, the effectiveness of protective measures taken against inhaling ash and eye exposure was evaluated by asking the participants for their subjective experience of the measures.
The study area of the volcanic eruption
The volcanic eruption of the Eyjafjallajökull volcanic system began on 20 March 2010 with a small flank eruption, which produced negligible ash. After a day of no volcanic activity, an eruption started within the Eyjafjallajökull caldera on 14 April.15 This phase was explosive, sending fine-grained, phreatomagmatic ash into the atmosphere. The eruption lasted some 6 weeks, until the end of May 2010. Ash exposure around the volcano was estimated using information about the eruption plume from satellite images (coarse time resolution), information about the emission intensity,1 and information from observations on the ground.16 Model calculations using FLEXPART5 gave similar distribution for the deposited ash, with maximum deposition around 1000 g/m2 (near the vent of the volcano) and about 200 g/m2 near Vík.4 During that time, the wind direction was predominantly west and north-west, therefore most of the ash fall was to the south and south-east of the volcano (figure 1). In this study, we included inhabitants of the area between the River Markarfljót and the village of Vík as they were most exposed. Most inhabitants are farmers, and many also have income from tourism.
The volcanic ash
The ash was trachyandesitic, 58% silica by mass, but contained very little quartz, and no cristobalite was detected.1–5 In ash samples collected during the first 3 days of the eruption, upwards of 25% of particles by mass were <10 μm in diameter (PM10) and therefore inhalable. The fraction of fine particles was lower for ash ejected later in the eruption,1 but still the amount of ash produced was considerable, and the fine-grained ash was also easily resuspended. The concentration of airborne particulate matter frequently exceeded the WHO guideline values for PM10 during the eruption.4
A network of diffusion tubes in the ground area showed no evidence of fumigation by sulphur dioxide, the predominant volcanic gas in the ash plume, in the last 3 weeks of the eruption (Personal communication: Peter Baxter, 2010).
Target population and recruitment
During the eruption, some 223 individuals lived in the study area and were exposed to ash fall. All the inhabitants were invited to a medical examination during the time period 31 May–11 June 2010. An announcement was put up in local official buildings and information given on radio and TV news. Also, inhabitants were contacted by telephone by staff from the two local primary healthcare centres in the area. The majority of participants were examined at temporary medical offices at a community centre or at a primary healthcare centre; a few were examined in their homes.
Medical and psychological examination
A physician interviewed and examined all participants. The physicians in charge were specialists in family medicine and respiratory medicine. Former and present physical and psychological health was explored. Participants were asked if they experienced any change in health or new symptoms that they related to the ash and the volcanic eruption. The medical history of young children was obtained from their parents. In case of abnormal findings, the participants were referred to their Primary Health Care Centre for further examination and treatment.
The forced expiratory volume in one second (FEV1) and the forced vital capacity (FVC) values were obtained by spirometry in all participants 5 years or older, according to the American Thoracic Society criteria in the same way and by the same fieldworkers as had conducted the Burden of Obstructive Lung Disease (BOLD) multicentre study in Iceland.1718 The spirometry was conducted by trained and certified personnel, and the medical examination was conducted by doctors, all from the Landspitali University Hospital.
Briefly, testing was conducted with the participant in a sitting position wearing a nose clip and a disposable mouthpiece using the NDD Easy One spirometer (NDD Medizintechnik, Zurich, Switzerland). Prebronchodilator and postbronchodilator tests were carried out, with separate measurements performed before and ≥15 min after two puffs of salbutamol (200 μg). The primary reference equations used are derived from the third United States National Health and Nutrition Examination Survey (NHANES III) for adult Caucasians.19
The criteria for chronic obstructive pulmonary disease (COPD) are defined by the Global Initiative of Chronic Obstructive Lung Disease.17 COPD GOLD stage I was defined as FEV1/FVC ratio <0.7 after bronchodilation and GOLD stage II as FEV1/FVC ratio <0.7 and FEV1 ≤80% predicted after bronchodilation. Reversibility of airway obstruction was calculated as a change in FEV1 and expressed as a change in percentage (∆%).
For analysis of the spirometry results in those older than 40 years, a subset of the BOLD cohort18 was used as a control group, with three age- and gender-matched controls from the BOLD (random general) population for each participant exposed to volcanic ash.
Participants older than 18 years were asked to fill out questionnaires with questions about physical health, mental health, exposure to volcanic ash, experience of earthquakes, rumbling and smell from the volcano, and use of protective face masks and glasses. If necessary, the questionnaires were read to them by researchers.
Respiratory health before the eruption was assessed by the European Community Respiratory Health Survey (ECRHS) II Questionnaire.20 From the main ECRSH Questionnaire, we used questions about wheeze, cough and phlegm prevalence, history of respiratory- and heart disease (questions number 1–3, 6–10 and 14, and question 7 from the screening questionnaire).
The participants were also asked if they had experienced other respiratory or eye symptoms, muscular pain, fatigue, nausea, headache, stomach pain or insomnia before and/or after the eruption started. If the symptoms had started after the eruption, they were asked to quantify how much these symptoms affected their daily life on a 3-point scale (rather little, rather much and very much).
Parents answered seven questions about respiratory symptoms, headache, stomach ache, insomnia, anxiety, depression and behavioural changes in children younger than 18 years. If these symptoms had started after the eruption, they were asked to quantify them on a three-level scale.
There were also questions about medical emergencies, use of medication, injuries, and accidents related to the eruption.
Mental health was assessed with three different psychometric scales, which all had previously been translated into Icelandic and used in other studies. When measuring psychological morbidity in relationship with the eruption, we used the General Health Questionnaire (GHQ-12),2122 the Depression Anxiety Stress Scale (DASS),23 and the Post-Traumatic Stress Disorder (PTSD) Symptom Scale, Self-Report version (PSS-SR).2425 Each questionnaire was evaluated, and, if inadequately answered, excluded.
For GHQ-12, a score of more than 2 was considered indicative of experiencing more mental distress than usual (Bimodal score).21
For PSS-SR, a score of more than 14 considered indicative of likelihood of PTSD symptoms in the participants.2425
For DASS, a score was given for each of the three dimensions addressed in the questionnaire. A score of more than 10 for depression, 8 for anxiety, and 15 for stress indicated symptom severity, from mild to extreme, as defined by Lovibond and Lovibond.23 DASS and PSS-SR questionnaires were not administered on the first day of the study, but participants were given the option of filling out the questionnaires and mailing them.
Participants were asked how they had experienced ash fall, heard or been awakened by noise from the volcano, felt earthquakes, smell or limited vision outside due to ash fall at their homes; how many days they had to stay inside because of ash fall; how many hours they usually worked outdoors and if they had used protective equipment. Finally, participants were asked if they had received help or services from a number of organisations and institutions, and if they were satisfied with it.
Smoking history was investigated by asking participants if they had ever smoked, and if they were current smokers. Based on this information, the participants were classified into never-smoker, former smoker and current smoker.
All data were entered into a database by one observer. The analysis was mainly descriptive, and the primary outcome measure was prevalence in percentage (%) of the total number of answers in the given category. In comparisons between groups, we used Student t test and χ2 test. Individuals with incomplete data were not excluded from the study, but non-replies to any single questions were excluded from individual analyses. We used SPSS software V.1826 and R.27
Altogether 207 out of 223 individuals (93%) who lived in the study area at the time of the eruption participated in the study. Local health workers, who recruited the participants, reported that inhabitants of two of about 80 farms had refused to participate, and 14 individuals who had initially signed up did not participate.
The most common reason for non-participation reported to the recruiters was either ‘being busy’, ‘not having any health problems’ or ‘old age’ (reported by relatives). Of the 207 participating residents, 40 were younger than 18 years. Most of them, 202 (98%) were medically examined, 164 adults and 38 children. The same proportion was tested with spirometry, and 156 adults were tested both before and after bronchodilation. All adults received questionnaires about symptoms and general health (GHQ-12). PSS-SR and DASS were administered to 150 people. Main demographic characteristics, symptom, and smoking rates reported by adults are shown in table 1. The survey included 40 children younger than 18 years, of which 21 (53%) were girls.
The age distribution of all participants is given in figure 2.
Age distribution of the study participants (n=207) from the Eyjafjallajökull area investigated from 31 May to 11 June 2010.
The physician's judgement was that 126 (62%) of the participants were healthy. In the physician interview, 26 (13%) of adults reported history of asthma or other chronic respiratory diseases, 32 (16%) reported symptoms and signs other than respiratory and 27 (13%) participants indicated a history of mental symptoms. Asthma rates reported to physicians were similar to those reported in questionnaires. Of those with a history of asthma or other respiratory diseases, 38% had a normal spirometric test, but 39% reported worsening of the disease when exposed to ash (table 1). Some reported to physicians that upper respiratory symptoms subsided when avoiding exposure by staying inside, wearing dust masks, and also that falling ‘fresh’ ash was more bothersome than ‘older’ ash re-suspended by wind. Farming was reported as the main occupation (63%) of adult participants.
Among the 202 participants who underwent spirometry, 37 (18%) were found to have impaired respiratory function by the examining physician.
Participants aged 40 years or older had on average a higher FEV1 than the reference group (p=0.003), and they also showed less airflow reversibility (p<0.0001). The rates of chronic cough and phlegm were similar in the study participants and the reference group (8%–10%). Smoking was more common in the reference group than the volcano-exposed participants (p<0.01). After bronchodilation, 20% of those aged 40 years or older fulfilled the criteria for COPD stage I or higher, which was identical to that found among the general population reference group (table 2).18
The 35 children who were tested with spirometry had a normal per cent of predicted FEV1 (102%±19%; mean, one SD) and FVC (104%±17%). Altogether four had FEV1% predicted lower than 85%; two of these had pre-existing asthma and revealed symptoms when examined (FEV1 48% and 76%, respectively), the other two were previously healthy, but both had symptoms of upper airway virus infection (FEV1 71% and 81%, respectively) when examined.
Spirometry results, smoking status, reported chronic respiratory diseases and symptoms among participants aged >40 years compared to an age- and gender-matched reference group from the general population
Almost half of the adult participants (43%) experienced symptoms from the upper airways and eyes during the ash fall. Almost everybody or 153 of 161 (96%) found facial mask and glasses protective against respiratory and eye symptoms when staying outdoor during ash fall. All participants of the study were exposed to ash fall at their homes, and almost all (88%) had to stay inside at least 1 day and one third (34%) for 6 days or more, which may explain some of the mental distress and child behavioural problems. Also, avoiding exposure by staying in the well-isolated houses may have kept symptom rates down. Almost everyone (98%) had heard the explosions from the mountain at their home, and 53% had woken up at night because of noise, but there was no obvious geographical pattern to this. The most common self-reported symptoms in adult participants are shown in table 1. Men and women had similar rates of symptoms, except that women tended to report more throat and upper airway irritation (p=0.06, Student t test).
Women reported more frequently mental health deterioration than men, according to the GHQ and DASS, and the highest rates were found in those between 35 and 49 years of age (table 3). Symptoms of post-traumatic stress syndrome (PSS-SR) were found in 7% of participants and were more common among women than men and in those slightly older (50–64 years old). Very little effect on mental health was reported in the age group 18–34 years.
Table 4 shows the proportions of participants experiencing mental distress by level of exposure (experience of the volcanic eruption). Experiencing a feeling of helplessness or fear for the lives of others or oneself during the eruption period was associated with higher rates of likely PTSD symptoms. The frequency of mental distress (as measured by the GHQ) was significantly (p<0.05) higher in those who had been awakened by noise.
Symptoms of depression and anxiety (DASS) were more common among those who had experienced earthquakes and had thought that their lives were in danger (table 4).
Many children of school age were not in the area during the heaviest ash fall. A boarding school outside the affected region invited the Eyjafjallajökull children to stay for some weeks. By the time the health survey was carried out, most were in the area. Nevertheless, 13 (28%) of parents reported in the questionnaires that their child had experienced throat or upper airway irritation symptoms (data not shown). Eight (13%) reported headaches, while three parents (7%) reported that their child or children had had nausea or stomach pain during the eruption. Of the 40 participating children, five had a history of asthma and they all reported in the medical interview that they had had more symptoms during the ash fall and needed more antiasthmatic medication than usual. Regarding mental distress, 39% of participants with children reported increased worries or anxiety in their children, 18% reported increased behaviour problems and 16% reported sleep-related problems.
Mental symptoms following the eruption of Eyjafjallajökull
Mental symptoms and experiences during the eruption of Eyjafjallajökull
Demographic characteristics and questionnaire-reported symptoms of participants who all lived close to the Eyjafjallajökull volcano (n=167)
In a well-defined rural population that had been exposed to volcanic ash particles with a substantial inhalable fraction for several weeks during the Eyjafjallajökull eruption, we found only a small degree of physical health impairments soon after the eruption. No hospital admissions, fatalities or life-threatening or serious symptoms or diseases that could be attributed to the eruption were found in this study cohort. From the answers to the questionnaires, we could conclude that compared to the general population sample from the BOLD study, the study participants reported a similar prevalence of respiratory symptoms and obstructive lung disease. Some symptoms of mental distress were found in this study.
In our study, we contacted the whole population living closest to the volcano and had a high participation rate (93%). According to the recruiters, some non-participators reported not having any health problems, so the symptom rates presented here may be overestimated. There may also be a recall bias, so that those who are worried about their health are more likely to participate and recall symptoms. On the other hand, some vulnerable individuals may have chosen not to participate or had left the most affected area, which may cause us to underestimate the symptom rates.
To facilitate comparisons with other studies, we used standardised methods in both the medical examinations and questionnaires, as well as the spirometry in this survey. However, the population is small (N=207, of which 167 were adults) and due to stressful circumstances during the test period, not all participants completed the questionnaire, which limited the statistical power of our analyses.
The participants from the Eyjafjallajökull area had better lung function than the general population sample, most likely due to a much lower prevalence of smoking. They also had less obstructed airways when tested again after use of a bronchodilator, probably because those with asthma had already increased their bronchodilator treatment during the ash fall. Also, the general population reference sample lived in urban and suburban areas, whereas the Eyjafjallajökull area is predominantly rural. The children had normal spirometry measurements. Previous studies have not found changes in lung function in children after volcanic ash exposure, but asthma hospitalisation rates have been seen to increase after several eruptions,1112 and a dose–response has also been found in a Japanese study of asthmatic adults who were exposed to volcanic ash.28
Intermittent symptoms in the eyes and upper respiratory organs were very common, but they could be prevented by wearing eye protection and face masks, or avoiding exposure by staying inside. Facial masks and glasses for eye protection were made widely and freely available by the public health authorities. These protective equipment were in plentiful supplies purchased for the swine flu epidemic the previous year. Icelandic houses are generally quite well insulated with windows that shut tightly and seemed to offer some protection.
It was recorded in several of the medical examination reports that people found the ash more irritating in the beginning of the eruption, perhaps because fresh ash particles can have chemical compounds on the surface, which are later washed away.23
In a study of the ash from Eyjafjallajökull, Horwell et al2 found most samples to have little potential for damaging health. The ash contained a negligible amount of crystalline silica, and though one sample showed some cytotoxicity in in vitro studies, the report concluded that the ash was unlikely to have an effect at the levels to which people were actually exposed.
The first results from a study of lung tissue samples and samples from the gastrointestinal tract of animals brought to slaughter from the affected area in the autumn of 2010 did not reveal any significant pathology.29
During the first days of the eruption, precautions for individuals with respiratory disease were issued throughout much of Europe, both by national health authorities but also by the WHO.30 Symptom surveillance studies, however, have shown a slight increase in the number of individuals on the European continent seeking medical help for certain symptoms in the period when the region was affected by ash.3132
In our study, 39% of participants reported some symptoms of mental distress, as measured by the GHQ. A high GHQ score was associated with feeling helpless or afraid or being awakened by noises from the volcano. The rate of GHQ cases in this study was more than twice as many as in a 2004 study of Icelandic farmers where 17% scored above the reference value for mental distress in the GHQ.33 However, in a Japanese study of a population exposed to a volcanic eruption, 66% were found to suffer from mental distress, but this population had been evacuated and were unable to return to their home region for years.14 Only half of the participants in this study population were evacuated, and then only for a few days.
The proportion of participants who exhibited symptoms of post-traumatic stress (7%) was similar to that found following a large earthquake in the south of Iceland in 2008.34 When the eruption was still active, there were substantial disturbances in people's daily routine. Some of the fatigue and stress indicated by the high prevalence of mental distress may be attributed to the increased workload during the eruption and at the same time the uncertainty about one's own health, the health of others, the livestock and the future. In addition, our results showed that increased mental distress might partly be explained by the extent of experience of volcanic phenomena, as it was associated with having experienced earthquakes related to the eruption or experiencing threat to one's own life or that of others. On the other hand, those who are distressed may experience these phenomena more strongly during an eruption. Information about the possible health effects of the ash was needed for the affected individuals. Therefore, early in the eruption, collaboration was established with national as well as international experts from the WHO and EU, and the International Volcanic Health Hazards Network, whose pamphlets were translated into Icelandic and distributed widely.35 Trauma response teams on behalf of the Red Cross were present in the evacuation and community centres, and a number of community meetings were held to inform the affected population.
During the time when volcanic ash was falling from the Eyjafjallajökull eruption, the majority of participants experienced symptoms from eyes and upper airways. Those with underlying obstructive lung disease were particularly vulnerable; half of the asthmatic adults and all the asthmatic children had more pronounced symptoms during the eruption.
Our results indicate that public health measures were effective in relieving symptoms. Recommendation to avoid exposure by either staying inside or wearing dust protection masks and glasses when outdoors during the ash fall or storms may have contributed to mitigation of irritation and symptoms.
During a volcanic ash fall, intensive medical attention should be aimed at vulnerable individuals with underlying respiratory diseases and known mental disorders.
Little is known about long-term health effects of exposure to volcanic ash, but continuous surveillance and research is necessary as the ash is likely to remain in the environment for some years to come. A follow-up study would be helpful in interpreting the spirometry results, but no severe health outcomes could be associated with the eruption in this study.
We thank Olof Arnadottir and Helga Thorbergsdottir, RN, South Iceland Primary Health Care Centre; Berglind Gudmundsdottir, psychologist, Landspitali-University Hospital; Edda Bjork Thordardottir, PhD student, University of Iceland; Gudrun Pétursdottir, PhD, University of Iceland Centre for Sustainability Studies; Kristinn Tomasson, MD, Administration of Occupational Safety and Health in Iceland; Urdur Njardvik, lector in psychology, University of Iceland; Ossur Ingi Emilsson, Cand. Med., University of Iceland; Halldora Brynjolfsdottir, Hildur Ragnarsdottir, Kristin Bara Jorundsdottir and Sigrun Gudmundsdottir, research specialists, Landspitali-University Hospital; Elísabet Magnusdottir, research assistant, University of Iceland and Agust Gunnar Gylfason, project manager in risk management, Icelandic civil protection service for their assistance in conducting this study.