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Background: Borderline personality disorder (BPD) is considered a disorder of emotion regulation resulting from the expression of a biologically determined emotional vulnerability (that is, heightened sensitivity to emotion, increased emotional intensity/reactivity, and a slow return to emotional baseline) combined with exposure to invalidating environments. Vagal tone has been associated with activity in cortical regions involved in emotion regulation and a lower resting state of vagal tone has been observed in BPD patients relative to healthy controls. Non-invasive transcutaneous auricular vagus nerve stimulation (taVNS) has been shown to reduce temper outbursts in adults with Prader-Willi Syndrome, to enhance recognition of emotions in healthy students, and to improve depressive and anxiety symptoms. Furthermore, a single session of taVNS has been shown to acutely alter the recognition of facial expressions of negative valence in adolescents with MDD and increase emotion recognition in controls. However, the effect of taVNS on emotional vulnerability and regulation in individuals diagnosed with BPD has not been investigated. Our aims are to determine if taVNS is effective in acutely reducing emotional vulnerability and improve emotional regulation in BPD patients., Methods: Forty-two patients will be randomized to a single session of taVNS or sham-taVNS while going through an affect induction procedure. It will consist of the presentation of one neutral and three negative affect-evoking 4-min-long videos in sequence, each of which is followed by a 4-min post-induction period during which participants will rate the quality and intensity of their current self-reported emotions (post-induction ratings) and the perceived effectiveness in managing their emotions during the video presentation. The rating of the current self-reported emotions will be repeated after every post-induction period (recovery ratings). Mixed models with individuals as random effect will be used to investigate the ratings at each stage of the study, taking into account the repeated measures of the same individuals at baseline, pre-induction, post-induction, and recovery., Discussion: The study has potential to yield new insights into the role of vagal tone in emotion dysregulation in BPD and offer preliminary data on the effectiveness of taVNS as a possible non-invasive brain stimulation to treat a core symptom of BPD., Trial Registration: ClinicalTrials.gov NCT05892900. Retrospectively registered on Jun 07, 2023., (© 2024. The Author(s).)

Background: The use of chatbots in mental health support has increased exponentially in recent years, with studies showing that they may be effective in treating mental health problems. More recently, the use of visual avatars called digital humans has been introduced. Digital humans have the capability to use facial expressions as another dimension in human-computer interactions. It is important to study the difference in emotional response and usability preferences between text-based chatbots and digital humans for interacting with mental health services., Objective: This study aims to explore to what extent a digital human interface and a text-only chatbot interface differed in usability when tested by healthy participants, using BETSY (Behavior, Emotion, Therapy System, and You) which uses 2 distinct interfaces: a digital human with anthropomorphic features and a text-only user interface. We also set out to explore how chatbot-generated conversations on mental health (specific to each interface) affected self-reported feelings and biometrics., Methods: We explored to what extent a digital human with anthropomorphic features differed from a traditional text-only chatbot regarding perception of usability through the System Usability Scale, emotional reactions through electroencephalography, and feelings of closeness. Healthy participants (n=45) were randomized to 2 groups that used a digital human with anthropomorphic features (n=25) or a text-only chatbot with no such features (n=20). The groups were compared by linear regression analysis and t tests., Results: No differences were observed between the text-only and digital human groups regarding demographic features. The mean System Usability Scale score was 75.34 (SD 10.01; range 57-90) for the text-only chatbot versus 64.80 (SD 14.14; range 40-90) for the digital human interface. Both groups scored their respective chatbot interfaces as average or above average in usability. Women were more likely to report feeling annoyed by BETSY., Conclusions: The text-only chatbot was perceived as significantly more user-friendly than the digital human, although there were no significant differences in electroencephalography measurements. Male participants exhibited lower levels of annoyance with both interfaces, contrary to previously reported findings., (©Almira Osmanovic Thunström, Hanne Krage Carlsen, Lilas Ali, Tomas Larson, Andreas Hellström, Steinn Steingrimsson. Originally published in JMIR Human Factors (https://humanfactors.jmir.org), 29.04.2024.)

Background: Type 2 diabetes (T2D) and peripheral artery disease (PAD) are recognized as independent risk factors contributing to excess mortality. Contemporary observational studies exploring the associations of risk factors, and risk of all-cause and atherosclerotic cardiovascular disease mortality in persons with T2D following the onset of incident peripheral artery disease are limited. The objectives of this study were to investigate the associations of risk factors, and assess mortality risks in people with T2D compared with controls without T2D after the onset of PAD., Methods: All persons with T2D (n = 150,215) registered in the Swedish National Diabetes Register between 2005 and 2009 were included, along with 346,423 controls without T2D matched for sex and age. Data were retrieved from several national registries, capturing information on risk factors, onset of incident peripheral artery disease, other comorbidities, socioeconomic factors, and outcomes. To compare persons with T2D and controls following the onset of peripheral artery disease regarding the risk of all-cause, and atherosclerotic cardiovascular disease mortality, Cox proportional hazard models and Kaplan-Meier curves were employed. A gradient-boosting model was utilized to estimate the relative statistical contribution of risk factors to the modeling of incident mortality risk in people with both T2D and peripheral artery disease., Results: Crude rates of incident all-cause mortality were higher in individuals with T2D compared with controls, following the onset of PAD (600.4 (95% CI, 581.4-619.8) per 10,000 person-years versus 549.1 (95% CI, 532.1-566.5) per 10,000 person-years). Persons with T2D had an adjusted hazard ratio (HR) for all-cause mortality of 1.12 (95% CI, 1.05-1.19, P < 0.01) compared with controls after onset of incident PAD. The comparable adjusted HR for cardiovascular mortality was 1.13 (95% CI, 1.07-1.19, P < 0.01). High age and hyperglycemia at baseline played a significant role in contributing to the predictive models for incident all-cause and cardiovascular mortality among individuals with both T2D and PAD., Conclusions: The presence of T2D with concomitant PAD is related to an increased risk of both all-cause and cardiovascular mortality compared with individuals with only PAD. This argues for implementing optimized and intensive treatment strategies for individuals with both conditions., (© 2024. The Author(s).)

Objective: To investigate to what extent having control of peripheral artery disease (PAD) risk factors is associated with the risk of incident PAD in individuals with type 2 diabetes., Research Design and Methods: A total of 148,096 individuals with type 2 diabetes in the Swedish National Diabetes Register between 2005 and 2009 were included and matched with 320,066 control subjects on the basis of age, sex, and county. A few control subjects who developed type 2 diabetes after recruitment, during wash-in (<0.2%), were not censored but instead matched with two new control subjects. Individuals with type 2 diabetes were evaluated according to the number of PAD risk factors beyond recommended guideline levels at baseline, including LDL cholesterol, blood pressure, smoking, glycated hemoglobin, and estimated glomerular filtration rate. Incident PAD events were ascertained from 2006 to 2019., Results: A graded association was observed between the number of PAD risk factors not at target and incident PAD in individuals with type 2 diabetes. The adjusted hazard ratio for PAD was 1.41 (95% CI 1.23-1.63) for those with type 2 diabetes with all PAD risk factors within target compared with control subjects matched for sex, age, and county but not risk factor status, in contrast with 9.28 (95% CI 3.62-23.79) for those with all five PAD risk factors not at target., Conclusions: A graded association was observed between increasing number of PAD risk factors not at target and incident PAD in individuals with type 2 diabetes., (© 2023 by the American Diabetes Association.)

Background: Air pollution is a large environmental health hazard whose exposure and health effects are unequally distributed among individuals. This is, at least in part, due to gene-environment interactions, but few studies exist. Thus, the current study aimed to explore genetic susceptibility to airway inflammation from short-term air pollution exposure through mechanisms of gene-environment interaction involving the SFTPA, GST and NOS genes., Methods: Five thousand seven hundred two adults were included. The outcome measure was fraction of exhaled nitric oxide (FeNO), at 50 and 270 ml/s. Exposures were ozone (O 3 ), particulate matter < 10 µm (PM 10 ), and nitrogen dioxide (NO 2 ) 3, 24, or 120-h prior to FeNO measurement. In the SFTPA, GST and NOS genes, 24 single nucleotide polymorphisms (SNPs) were analyzed for interaction effects. The data were analyzed using quantile regression in both single-and multipollutant models., Results: Significant interactions between SNPs and air pollution were found for six SNPs (p < 0.05): rs4253527 (SFTPA1) with O 3 and NO x , rs2266637 (GSTT1) with NO 2 , rs4795051 (NOS2) with PM 10 , NO 2 and NO x , rs4796017 (NOS2) with PM 10 , rs2248814 (NOS2) with PM 10 and rs7830 (NOS3) with NO 2 . The marginal effects on FeNO for three of these SNPs were significant (per increase of 10 µg/m 3 ):rs4253527 (SFTPA1) with O 3 (β: 0.155, 95%CI: 0.013-0.297), rs4795051 (NOS2) with PM 10 (β: 0.073, 95%CI: 0.00-0.147 (single pollutant), β: 0.081, 95%CI: 0.004-0.159 (multipollutant)) and NO 2 (β: -0.084, 95%CI: -0.147; -0.020 (3 h), β: -0.188, 95%CI: -0.359; -0.018 (120 h)) and rs4796017 (NOS2) with PM 10 (β: 0.396, 95%CI: 0.003-0.790)., Conclusions: Increased inflammatory response from air pollution exposure was observed among subjects with polymorphisms in SFTPA1, GSTT1, and NOS genes, where O 3 interacted with SFTPA1 and PM10 and NO 2 /NO x with the GSTT1 and NOS genes. This provides a basis for the further exploration of biological mechanisms as well as the identification of individuals susceptible to the effects of outdoor air pollution., (© 2023. The Author(s).)

Background: Previous research suggests an association between road traffic noise and obesity, but current evidence is inconclusive. The aim of this study was to assess the association between nocturnal noise exposure and markers of obesity and to assess whether sleep disturbance might be a mediator in this association., Methods: We applied data from the Respiratory Health in Northern Europe (RHINE) cohort. We used self-measured waist circumference (WC) and body mass index (BMI) as outcome values. Noise exposure was assessed as perceived traffic noise in the bedroom and/or the bedroom window's location towards the street. We applied adjusted linear, and logistic regression models, evaluated effect modifications and conducted mediation analysis., Results: Based on fully adjusted models we found that women, who reported very high traffic noise levels in bedroom, had 1.30 (95% CI 0.24-2.37) kg/m 2 higher BMI and 3.30 (95% CI 0.39-6.20) cm higher WC compared to women, who reported no traffic noise in the bedroom. Women who reported higher exposure to road traffic noise had statistically significant higher odds of being overweight and have abdominal obesity with OR varying from 1.15 to 1.26 compared to women, who reported no traffic noise in the bedroom. For men, the associations were rather opposite, although mostly statistically insignificant. Furthermore, men, who reported much or very much traffic noise in the bedroom, had a statistically significantly lower risk of abdominal obesity. Sleep disturbance fully or partially mediated the association between noise in bedroom and obesity markers among women., Conclusion: Our results suggest that self-reported traffic noise in the bedroom may be associated to being overweight or obese trough sleep disturbance among women, but associations were inconclusive among men., (© 2023. The Author(s).)

Background: The developing lung is highly susceptible to environmental toxicants, with both short- and long-term exposure to ambient air pollutants linked to early childhood effects. This study assessed the short-term exposure effects of nitrogen dioxide (NO 2 ) and particulate matter (PM 10 ) on lung function in infants aged 6 weeks, 6, 12 and 24 months, the early developmental phase of child growth., Methods: Lung function was determined by multiple breath washout and tidal breathing measurement in non-sedated infants. Individual exposure to NO 2 and PM 10 was determined by hybrid land use regression and dispersion modelling, with two-week average estimates (preceding the test date). Linear mixed models were used to adjust for the repeated measures design and an age*exposure interaction was introduced to obtain effect estimates for each age group., Results: There were 165 infants that had lung function testing, with 82 of them having more than one test occasion. Exposure to PM 10 (μg/m 3 ) resulted in a decline in tidal volume at 6 weeks [-0.4 ml (-0.9; 0.0), p = 0.065], 6 months [-0.5 ml (-1.0; 0.0), p = 0.046] and 12 months [-0.3 ml (-0.7; 0.0), p = 0.045]. PM 10 was related to an increase in respiratory rate and minute ventilation, while a decline was observed for functional residual capacity for the same age groups, though not statistically significant for these outcomes. Such associations were however less evident for exposure to NO 2 , with inconsistent changes observed across measurement parameters and age groups., Conclusion: Our study suggests that PM 10 results in acute lung function impairments among infants from a low-socioeconomic setting, while the association with NO 2 is less convincing., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Evidence of the role of interactions between air pollution and pollen exposure in subjects with allergic asthma is limited and need further exploration to promote adequate preventive measures. The objective of this study was to assess effects of exposure to ambient air pollution and birch pollen on exacerbation of respiratory symptoms in subjects with asthma and allergy to birch., Methods: Thirty-seven subjects from two Swedish cities (Gothenburg and Umeå) with large variation in exposure to both birch-pollen and air pollutants, participated in the study. All subjects had confirmed allergy to birch and self-reported physician-diagnosed asthma. The subjects recorded respiratory symptoms such as rhinitis or eye irritation, dry cough, dyspnoea, the use of any asthma or allergy medication and peak respiratory flow (PEF), daily for five consecutive weeks during two separate pollen seasons and a control season without pollen. Nitrogen oxides (NO x ), ozone (O 3 ), particulate matter (PM 2.5 ), birch pollen counts, and meteorological data were obtained from an urban background monitoring stations in the study city centres. The data were analysed using linear mixed effects models., Results: During pollen seasons all symptoms and medication use were higher, and PEF was reduced in the subjects. In regression analysis, exposure to pollen at lags 0 to 2 days, and lags 0 to 6 days was associated with increased ORs of symptoms and decreased RRs for PEF. Pollen and air pollution interacted in some cases; during low pollen exposure, there were no associations between air pollution and symptoms, but during high pollen exposure, O 3 concentrations were associated with increased OR of rhinitis or eye irritation, and PM 2.5 concentrations were associated with increased ORs of rhinitis or eye irritation, dyspnea and increased use of allergy medication., Conclusions: Pollen and air pollutants interacted to increase the effect of air pollution on respiratory symptoms in allergic asthma. Implementing the results from this study, advisories for individuals with allergic asthma could be improved, minimizing the morbidities associated with the condition., (© 2022. The Author(s).)

Background: Air pollution is associated with cardiovascular morbidity and mortality, but its role in the development of congestive heart failure (CHF) and the role of different pollution sources in cardiovascular disease remain uncertain., Methods: Participants were enrolled in the Malmö Diet and Cancer cohort in 1991-1996 with information on lifestyle and clinical indicators of cardiovascular disease. The cohort participants were followed through registers until 2016. Annual total and local source-specific concentrations of particulate matter less than 10 μm and 2.5 μm (PM 10 and PM 2.5 ), black carbon (BC), and nitrogen oxides (NO x ) from traffic, residential heating, and industry were assigned to each participant's address throughout the study period. Cox proportional hazards models adjusted for possible confounders was used to estimate associations between air pollution 1-5 years prior to outcomes of incident CHF, fatal myocardial infarction (MI), major adverse coronary events (MACE), and ischemic stroke., Results: Air pollution exposure levels (mean annual exposures to PM 2.5 of 11 μg/m 3 and NO x of 26 μg/m 3 ) within the cohort were moderate in terms of environmental standards. After adjusting for confounders, we observed statistically significant associations between NO x and CHF (hazard ratio [HR] 1.11, 95% confidence interval [CI] 1.01-1.22) and NO x and fatal MI (HR 1.10, 95%CI 1.01-1.20) per interquartile range (IQR) of 9.6 μg/m 3 . In fully adjusted models, the estimates were similar, but the precision worse. In stratified analyses, the associations were stronger in males, ever-smokers, older participants, and those with baseline carotid artery plaques. Locally emitted and traffic-related air pollutants generally showed positive associations with CHF and fatal MI. There were no associations between air pollution and MACE or stroke., Discussion/conclusion: In an area with low to moderate air pollution exposure, we observed significant associations of long-term residential NO x with increased risk of incident CHF and fatal MI, but not with coronary events and stroke., (Copyright © 2022. Published by Elsevier Inc.)

Objectives: To assess the trends in medication use indicative of physical and psychological morbidity following the 2010 volcanic eruption in Eyjafjallajökull immediately after and during a 3-year period following the eruption., Design: Population-based register study., Setting: Eyjafjallajökull eruption in Iceland, 2007-2013., Participants: All residents in Iceland who received at least one medication dispensing were identified. Residents of exposed areas were classified into exposure groups (individual-level data) and residents in other parts of Iceland were included as a non-exposed group (aggregated data)., Intervention/exposure: Eyjafjallajökull erupted on 14 April 2010 and continued for 39 days, producing heavy ash fall in South Iceland., Main Outcome Measures: Using interrupted time series analysis, we examined annual and quarterly changes in medicine use, measured as number of dispensed defined daily dose (DDD) per 1000 individuals. We calculated the level shift (immediate change) and change in slope from pre-eruption to post-eruption (long-term change) in medication dispensing., Results: Among exposed residents, there was a 6% decrease (95% CI -7% to -4%) in the annual number of dispensed DDDs 1-year post-eruption in the overall medication class, including analgesics (-5%, 95% CI -6% to -3%), hypnotics and sedatives (-9%, 95% CI -11% to -7%) and respiratory medications (-7%, 95% CI -9% to -5%; -8%, 95% CI -11% to -4%). Simultaneously, there was a 9% decrease (95% CI -14% to -4%) in the overall medication class among non-exposed residents. Moreover, among exposed residents, we observed change in slope of -4% (95% CI -7% to -1%) in the overall medication class, including for analgesics (-6%, 95% CI -8% to -3%) and other respiratory drugs (-10%, 95% CI -16% to -4%)., Conclusion: Our findings indicate that the eruption did not lead to increases in medication dispensing among residents of exposed areas, rather decreases for some medicine classes. The results should be interpreted with caution since the content of each eruption differs., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Ambient particulate matter is a leading risk factor for disease globally. Particulate matter 10 (PM 10 ) and particulate matter 2.5 (PM 2.5 ) are derived from different sources, including operating motor vehicles as well as from industrial activities. In this study we investigate the association between increased concentrations of PM and total daily visits to the psychiatric emergency unit (PEV). Further, the aim is to identify specific risk groups who are more susceptible to the effects of air pollution exposure by studying sex, age, ongoing psychiatric follow-up and diagnoses of depression/anxiety or substance use., Material and Methods: The sample was comprised of data from 2740 days to 81 548 PEVs at Sahlgrenska University Hospital in Gothenburg and daily mean concentrations of PM 10 and PM 2.5 . A time-stratified case-crossover design was used to analyse associations between air pollution and PEVs., Results: Mean number of daily PEVs were 35 and sex distribution was even. PM exposure was associated with total PEV at lag 0 (the same day), by RR 1.016 (95% confidence interval [CI] 1.004-1.028) and RR 1.020 (95%CI 1.003-1.038) per 10 μg/m 3 increase in PM 10 and PM 2.5 , respectively. In females, PEV were increased at lag 0 and lag 1, and in males at lag 1 and lag 2. In the age-stratified analysis, PEVs significantly increased following PM exposure amongst individuals aged 35-65 years by lag 0-2 and in individuals who had contact with outpatient care at lag 0 to lag 1. There were no associations between air pollution and PEVs for any specific diagnostic group evaluated (amongst depression, anxiety and substance use disorder)., Conclusions: The results indicate that acute exposure to PM 10 and PM 2.5 may trigger acute worsening in mental health in both males and females, especially among 35-65 year old individuals. However, in subgroups of the most common psychiatric diagnoses, we did not observe statistically significant associations with PM exposure., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Long-term air pollution exposure increases the risk for cardiovascular disease, but little is known about the temporal relationships between exposure and health outcomes. This study aims to estimate the exposure-lag response between air pollution exposure and risk for ischemic heart disease (IHD) and stroke incidence by applying distributed lag non-linear models (DLNMs). Annual mean concentrations of particles with aerodynamic diameter less than 2.5 µm (PM 2.5 ) and black carbon (BC) were estimated for participants in five Swedish cohorts using dispersion models. Simultaneous estimates of exposure lags 1-10 years using DLNMs were compared with separate year specific (single lag) estimates and estimates for lag 1-5- and 6-10-years using moving average exposure. The DLNM estimated no exposure lag-response between PM 2.5 total, BC, and IHD. However, for PM 2.5 from local sources, a 20% risk increase per 1 µg/m 3 for 1-year lag was estimated. A risk increase for stroke was suggested in relation to lags 2-4-year PM 2.5 and BC, and also lags 8-9-years BC. No associations were shown in single lag models. Increased risk estimates for stroke in relation to lag 1-5- and 6-10-years BC moving averages were observed. Estimates generally supported a greater contribution to increased risk from exposure windows closer in time to incident IHD and incident stroke.

The COVID-19 pandemic has caused societal restrictions and public fear which may have impacted the pattern of seeking psychiatric care. There has generally been a decrease in the numbers seeking acute psychiatric care. It is important to investigate which groups seeking psychiatric treatment have decreased in number. The aim of our investigation was to identify which groups have a changed pattern in acute psychiatric service utilization during the first two waves of the COVID-19 pandemic. The study investigated changes in the rate and pattern of visits and hospital admissions for psychiatric disorders at a large Swedish hospital. A register-based study was conducted using administrative data on adult psychiatric emergency department visits (PEVs) and hospital admission rates. Data during the first two COVID-19 waves were compared to corresponding control periods in 2018-2019. Furthermore, a survey was performed among patients visiting the Psychiatric Emergency Department on their views of COVID-19 and acute psychiatric care. During the COVID-19 periods, PEVs were reduced overall by 16 and 15% during the first and second wave, respectively ( p < 0.001 in both cases), while the rate of admissions remained unaltered. PEVs were significantly reduced for most psychiatric diagnosis subgroups except for patients with schizophrenia and other related psychotic disorders as well as for those who required ongoing outpatient care. Most of the survey respondents disagreed that the pandemic affected their visit and about a quarter thought a video call with a doctor could have replaced their visit. In conclusion, there was a significant reduction in overall PEVs during both COVID-19 waves but this did not affect the numbers requiring admission for psychiatric inpatient care., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Hamlin, Ymerson, Carlsen, Dellepiane, Falk, Ioannou and Steingrimsson.)

Exposure to air pollution is of great concern for public health although studies on the associations between exposure estimates and personal exposure are limited and somewhat inconsistent. The aim of this study was to quantify the associations between personal nitrogen oxides (NO x ), ozone (O 3 ) and particulate matter (PM 10 ) exposure levels and ambient levels, and the impact of climate and time spent outdoors in two cities in Sweden. Subjects (n = 65) from two Swedish cities participated in the study. The study protocol included personal exposure measurements at three occasions, or waves. Personal exposure measurements were performed for NO x and O 3 for 24 h and PM 10 for 24 h, and the participants kept an activity diary. Stationary monitoring stations provided hourly data of NO x , O 3 and PM, as well as data on air temperature and relative humidity. Data were analysed using mixed linear models with the subject-id as a random effect and stationary exposure and covariates as fixed effects. Personal exposure levels of NO x , O 3 and PM 10 were significantly associated with levels measured at air pollution monitoring stations. The associations persisted after adjusting for temperature, relative humidity, city and wave, but the modelled estimates were slightly attenuated from 2.4% (95% CI 1.8-2.9) to 2.0% (0.97-2.94%) for NO x , from 3.7% (95% CI 3.1-4.4) to 2.1% (95% CI 1.1-2.9%) for O 3 and from 2.6% (95% 0.9-4.2%) to 1.3% (95% CI - 1.5-4.0) for PM 10 . After adding covariates, the degree of explanation offered by the model (coefficient of determination, or R 2 ) did not change for NO x (0.64 to 0.63) but increased from 0.46 to 0.63 for O 3 , and from 0.38 to 0.43 for PM 10 . Personal exposure to NO x , O 3 and PM has moderate to good association with levels measured at urban background sites. The results indicate that stationary measurements are valid as measure of exposure in environmental health risk assessments, especially if they can be refined using activity diaries and meteorological data. Approximately 50-70% of the variation of the personal exposure was explained by the stationary measurement, implying occurrence of misclassification in studies using more crude exposure metrics, potentially leading to underestimates of the effects of exposure to ambient air pollution., (© 2021. The Author(s).)

The 2014-15 Holuhraun eruption in Iceland was the largest fissure eruption in over 200 years, emitting prodigious amounts of gas and particulate matter into the troposphere. Reykjavík, the capital area of Iceland (250 km from eruption site) was exposed to air pollution events from advection of (i) a relatively young and chemically primitive volcanic plume with a high sulphur dioxide gas (SO 2 ) to sulphate PM (SO 4 2- ) ratio, and (ii) an older and chemically mature volcanic plume with a low SO 2 /SO 4 2- ratio. Whereas the advection and air pollution caused by the primitive plume were successfully forecast and forewarned in public advisories, the mature plume was not. Here, we show that exposure to the mature plume is associated with an increase in register-measured health care utilisation for respiratory disease by 23% (95% CI 19.7-27.4%) and for asthma medication dispensing by 19.3% (95% CI 9.6-29.1%). Absence of public advisories is associated with increases in visits to primary care medical doctors and to the hospital emergency department. We recommend that operational response to volcanic air pollution considers both primitive and mature types of plumes.

Background: The Holuhraun volcanic eruption September 2014 to February 2015 emitted large amounts of sulfur dioxide (SO 2 ). The aim of this study was to determine the association between volcanic SO 2 gases on general population respiratory health some 250 km from the eruption site, in the Icelandic capital area., Methods: Respiratory health outcomes were: asthma medication dispensing (AMD) from the Icelandic Medicines Register, medical doctor consultations in primary care (PCMD) and hospital emergency department visits (HED) in Reykjavík (population: 215000) for respiratory disease from 1 January 2010 to 31 December 2014. The associations between daily counts of health events and daily mean SO 2 concentration and high SO 2 levels (24-h mean SO 2  > 125 μg/m3) were analysed using generalized additive models., Results: After the eruption began, AMD was higher than before (129.4 vs. 158.4 individuals per day, p < 0.05). For PCMD and HED, there were no significant differences between the number of daily events before and after the eruption (142.2 vs 144.8 and 18.3 vs 17.5, respectively). In regression analysis adjusted for other pollutants, SO 2 was associated with estimated increases in AMD by 0.99% (95% CI 0.39-1.58%) per 10 μg/m 3 at lag 0-2, in PCMD for respiratory causes 1.26% (95% CI 0.72-1.80%) per 10 μg/m 3 SO 2 at lag 0-2, and in HED by 1.02% (95% CI 0.02-2.03%) per 10 μg/m 3 SO 2 at lag 0-2. For days over the health limit, the estimated increases were 10.9% (95% CI 2.1-19.6%), 17.2% (95% CI 10.0-24.4%) for AMD and PCMD. Dispensing of short-acting medication increased significantly by 1.09% (95% CI 0.49-1.70%), and PCMD for respiratory infections and asthma and COPD diagnoses and increased significantly by 1.12% (95% CI 0.54-1.71%) and 2.08% (1.13-3.04%)., Conclusion: High levels of volcanic SO 2 are associated with increases in dispensing of AMD, and health care utilization in primary and tertiary care. Individuals with prevalent respiratory disease may be particularly susceptible.

Objectives: To investigate the long-term effects of source-specific particle matter (PM) on lung function, effects of Surfactant Protein A (SP-A) and glutathione S-transferase (GST) genes GSTP1 and GSTT1 gene variants and effect modification by single-nucleotide polymorphism (SNP) genotype., Design: Cohort study with address-based annual PM exposure assigned from annual estimates of size (PM 10 , PM 2.5 and PM BC ) and source-specific (traffic, industry, marine traffic and wood burning) dispersion modelling., Setting: Gothenburg, Sweden., Participants: The ADult-Onset asthma and NItric oXide Study had 6685 participants recruited from the general population, of which 5216 (78%) were included in the current study with information on all variables of interest. Mean age at the time of enrolment was 51.4 years (range 24-76) and 2427 (46.5%) were men., Primary and Secondary Outcome Measures: The primary outcome was forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV 1 ). Secondary outcome measures were effects and gene-environment interactions of SP-A and GSTT1 and GSTP1 genotypes., Results: Exposure to traffic-related PM 10 and PM 2.5 was associated with decreases in percent-predicted (% predicted) FEV 1 by -0.48% (95% CI -0.89% to -0.07%) and -0.47% (95% CI -0.88% to -0.07%) per IQR 3.05 and 2.47 µg/m 3 , respectively, and with decreases in % predicted FVC by -0.46% (95% CI -0.83% to -0.08%) and -0.47% (95% CI -0.83% to -0.10%). Total and traffic-related PM BC was strongly associated with both FEV 1 and FVC by -0.53 (95% CI -0.94 to -0.13%) and -0.43% (95% CI -0.77 to -0.09%) per IQR, respectively, for FVC, and similarly for FEV 1 . Minor allele carrier status for two GSTP1 SNPs and the GSTT1 null genotype were associated with decreases in % predicted lung function. Three SP-A SNPs showed effect modification with exposure to PM 2.5 from industry and marine traffic., Conclusions: PM exposure, specifically traffic related, was associated with FVC and FEV 1 reductions and not modified by genotype. Genetic effect modification was suggested for industry and marine traffic PM 2.5 ., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective The Holuhraun eruption of fall and winter 2014-15 produced large amounts of sulfur dioxide (SO 2 ). The aim of this study was to determine if exposure to extreme SO 2 levels affected the health of individuals working at the eruption site. Methods During January‒March 2015, earth scientists, technicians, and law enforcement personnel who were about to work at the eruption site were invited to a respiratory health examination. Symptom reports and lung function measures, forced expiratory volume in one second (FEV 1 ) and forced vital capacity (FVC) were collected before and after an eruption site visit. Those with previous exposure (N=27) reported symptoms retrospectively. Results Altogether, 41 individuals were invited to participate, 32 underwent a clinical examination at a hospital respiratory health clinic (baseline); 27 reported symptoms during earlier visits to the eruption site (retrospective symptom reports), 17 were re-examined 1-6 days after visiting the eruption site (follow-up). All participants' lung function was within normal range both before and after exposure. At baseline, average FEV 1 was 107.4% of predicted versus 106.6 at follow-up (P =0.82); average FVC was 107.0% of predicted at baseline versus 107.4% at follow-up (P=0.35). Eye and nasal irritation were more frequently reported during eruption site exposure by 24% versus 6% (P =0.37) for both. Conclusion Although "healthy-worker" effects cannot be excluded, our data indicate that SO 2 exposure was associated with relatively mild and transient respiratory symptoms with no clinical signs of airway inflammation or airway obstruction.

High or low ambient temperatures pose a risk factor for the worsening or onset of psychiatric disorders. The aim of this study was to investigate the association between ambient temperature and psychiatric emergency visits in an urban region in a temperate climate. The daily number of visits to a psychiatric emergency room (PEVs) at Sahlgrenska University Hospital, Gothenburg, Sweden and the daily mean temperature were extracted for the study period 1 July 2012 to 31 December 2017. Case-crossover analysis with distributed lag non-linear models was used to analyse the data by season. The warm season was defined as May to August and the cold season as November to February. Shorter lags periods were used for the warm season than the cold season. In the analysis, temperatures at the 95th percentile was associated with 14% (95% confidence interval (CI): 2%, 28%) increase in PEVs at lag 0⁻3 and 22% (95%CI: 6%, 40%) for lags 0⁻14 during the warm season, relative to the seasonal minimum effect temperature (MET). During the cold season temperatures at the 5th percentile were associated with 25% (95% CI: -8%, 13%) and 18% (95% CI: -30%, 98%) increase in PEVs at lags 0⁻14 and 0⁻21 respectively. We observed an increased number of PEVs at high and low temperatures; however, not to a statistically significant extent for low temperatures. Our findings are similar to what has been found for somatic diseases and in studies of other mental health outcomes in regions with more extreme climates. This merits the inclusion of individuals with psychiatric disorders in awareness planning for climate warning systems.

Background: Air pollution is one of the leading causes of mortality and morbidity worldwide. Experimental studies, and a few epidemiological studies, suggest that air pollution may cause acute exacerbation of psychiatric disorders, and even increase the rate of suicide attempts, but epidemiological studies on air pollution in association with psychiatric disorders are still few. Our aim was to investigate associations between daily fluctuations in air pollution concentrations and the daily number of visits to a psychiatric emergency unit., Methods: Data from Sahlgrenska University Hospital, Gothenburg, Sweden, on the daily number of visits to the Psychiatric emergency unit were combined with daily data on monitored concentrations of respirable particulate matter(PM 10 ), ozone(O 3 ), nitrogen dioxides(NO 2 ) and temperature between 1st July 2012 and 31st December 2016. We used a case-crossover design to analyze data with conditional Poisson regression models allowing for over-dispersion. We stratified data on season., Results: Visits increased with increasing PM 10 levels during the warmer season (April to September) in both single-pollutant and two-pollutant models. For example, an increase of 3.6% (95% Confidence Interval, CI, 0.4-7.0%) was observed with a 10 μg/m3 increase in PM 10 adjusted for NO 2 . In the three-pollutant models (adjusting for NO 2 and O 3 simultaneously) the increase was 3.3% (95% CI, -0.2-6.9). There were no clear associations between the outcome and NO 2 , O 3 , or PM 10 during the colder season (October to March)., Conclusions: Ambient air particle concentrations were associated with the number of visits to the Psychiatric emergency unit in the warm season. The results were only borderline statistically significant in the fully adjusted (three-pollutant) models in this small study. The observation could be interpreted as indicative of air pollution as either exacerbating an underlying psychiatric disorder, or increasing mental distress, even in areas with comparatively low levels of air pollution. In combination with the severe impact of psychiatric disorders and mental distress on society and individuals, our results are a strong warrant for future research in this area.

Objectives: To examine the long-term development of physical and mental health following exposure to a volcanic eruption., Design: Population-based prospective cohort study., Setting: In spring 2010, the Icelandic volcano Eyjafjallajökull erupted. Data were collected at 2 time points: in 2010 and 2013., Participants: Adult residents in areas close to the Eyjafjallajökull volcano (N=1096), divided according to exposure levels, and a non-exposed sample (n=475), with 80% participation rate in 2013., Main Outcome Measures: Physical symptoms in the previous year (chronic) and previous month (recent), and psychological distress (General Health Questionnaire-12-item version, GHQ-12), perceived stress (Perceived Stress Scale, PSS-4) and post traumatic stress disorder (PTSD) symptoms (Primary Care PTSD, PC-PTSD)., Results: In the exposed group, certain symptoms were higher in 2013 than in 2010, for example, morning phlegm during winter (OR 2.14; 95% CI 1.49 to 3.06), skin rash/eczema (OR 2.86; 95% CI 1.76 to 4.65), back pain (OR 1.45; 95% CI 1.03 to 2.05) and insomnia (OR 1.53; 95% CI 1.01 to 2.30), in addition to a higher prevalence of regular use of certain medications (eg, for asthma (OR 2.80; 95% CI 1.01 to 7.77)). PTSD symptoms decreased between 2010 and 2013 (OR 0.33; 95% CI 0.17 to 0.61), while the prevalence of psychological distress and perceived stress remained similar. In 2013, the exposed group showed a higher prevalence of various respiratory symptoms than did the non-exposed group, such as wheezing without a cold (high exposure OR 2.35; 95% CI 1.27 to 4.47) and phlegm (high exposure OR 2.81; 95% CI 1.48 to 5.55), some symptoms reflecting the degree of exposure (eg, nocturnal chest tightness (medium exposed OR 3.09; 95% CI 1.21 to 10.46; high exposed OR 3.42; 95% CI 1.30 to 11.79))., Conclusions: The findings indicate that people exposed to a volcanic eruption, especially those most exposed, exhibit increased risk of certain symptoms 3-4 years after the eruption., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/)

Coarse particle matter, PMcoarse, is associated with increased respiratory morbidity and mortality. The aim of this study was to investigate the association between short-term changes in PMcoarse and sub-clininal airway inflammation in children. Healthy children aged 11 years from two northern Swedish elementary schools underwent fraction of exhaled nitrogen oxide (FENO) measurements to determine levels of airway inflammation twice weekly during the study period from 11 April-6 June 2011. Daily exposure to PMcoarse, PM2.5, NO₂, NOx, NO and O₃ and birch pollen was estimated. Multiple linear regression was used. Personal covariates were included as fixed effects and subjects were included as a random effect. In total, 95 children participated in the study, and in all 493 FENO measurements were made. The mean level of PMcoarse was 16.1 μg/m³ (range 4.1-42.3), and that of O₃ was 75.0 μg/m³ (range: 51.3-106.3). That of NO₂ was 17.0 μg/m³ (range: 4.7-31.3), NOx was 82.1 μg/m³ (range: 13.3-165.3), and NO was 65 μg/m³ (range: 8.7-138.4) during the study period. In multi-pollutant models an interquartile range increase in 24 h PMcoarse was associated with increases in FENO by between 6.9 ppb (95% confidence interval 0.0-14) and 7.3 ppb (95% confidence interval 0.4-14.9). PMcoarse was associated with an increase in FENO, indicating sub-clinical airway inflammation in healthy children.

Background: The adverse health effects of high concentrations of hydrogen sulfide (H2S) exposure are well known, though the possible effects of low concentrations have not been thoroughly studied. The aim was to study short-term associations between modelled ambient low-level concentrations of intermittent hydrogen sulfide (H2S) and emergency hospital visits with heart diseases (HD), respiratory diseases, and stroke as primary diagnosis., Methods: The study is population-based, using data from patient-, and population-registers from the only acute care institution in the Reykjavik capital area, between 1 January, 2007 and 30 June, 2014. The study population was individuals (≥18yr) living in the Reykjavik capital area. The H2S emission originates from a geothermal power plant in the vicinity. A model was used to estimate H2S exposure in different sections of the area. A generalized linear model assuming Poisson distribution was used to investigate the association between emergency hospital visits and H2S exposure. Distributed lag models were adjusted for seasonality, gender, age, traffic zones, and other relevant factors. Lag days from 0 to 4 were considered., Results: The total number of emergency hospital visits was 32961 with a mean age of 70 years. In fully adjusted un-stratified models, H2S concentrations exceeding 7.00μg/m3 were associated with increases in emergency hospital visits with HD as primary diagnosis at lag 0 risk ratio (RR): 1.067; 95% confidence interval (CI): 1.024-1.111, lag 2 RR: 1.049; 95%CI: 1.005-1.095, and lag 4 RR: 1.046; 95%CI: 1.004-1.089. Among males an association was found between H2S concentrations exceeding 7.00μg/m3, and HD at lag 0 RR: 1.087; 95%CI: 1.032-1.146 and lag 4 RR: 1080; 95%CI: 1.025-1.138; and among those 73 years and older at lag 0 RR: 1.075; 95%CI: 1.014-1.140 and lag 3 RR: 1.072; 95%CI: 1.009-1.139. No associations were found with other diseases., Conclusions: The study showed an association between emergency hospital visits with HD as primary diagnosis and same day H2S concentrations exceeding 7.00μg/m3, more pronounced among males and those 73 years and older than among females and younger individuals.

Objectives: To investigate the association between living near dense traffic and lung function in a cohort of adults from a single urban region., Design: Cross-sectional results from a cohort study., Setting: The adult-onset asthma and exhaled nitric oxide (ADONIX) cohort, sampled during 2001-2008 in Gothenburg, Sweden. Exposure was expressed as the distance from participants' residential address to the nearest road with dense traffic (>10,000 vehicles per day) or very dense traffic (>30,000 vehicles per day). The exposure categories were: low (>500 m; reference), medium (75-500 m) or high (<75 m)., Participants: The source population was a population-based cohort of adults (n=6153). The study population included 5441 participants of European descent with good quality spirometry and information about all outcomes and covariates., Outcome Measures: Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1) were measured at a clinical examination. The association with exposure was examined using linear regression adjusting for age, gender, body mass index, smoking status and education in all participants and stratified by sex, smoking status and respiratory health status., Results: We identified a significant dose-response trend between exposure category and FEV1 (p=0.03) and borderline significant trend for FVC (p=0.06) after adjusting for covariates. High exposure was associated with lower FEV1 (-1.0%, 95% CI -2.5% to 0.5%) and lower FVC (-0.9%, 95% CI -2.2% to 0.4%). The effect appeared to be stronger in women. In highly exposed individuals with current asthma or chronic obstructive pulmonary disease, FVC was lower (-4.5%, 95% CI -8.8% to -0.1%)., Conclusions: High traffic exposure at the residential address was associated with lower than predicted FEV1 and FVC lung function compared with living further away in a large general population cohort. There were particular effects on women and individuals with obstructive disease., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

Volcanic ash contributed significantly to particulate matter (PM) in Iceland following the eruptions in Eyjafjallajökull 2010 and Grímsvötn 2011. This study aimed to investigate the association between different PM sources and emergency hospital visits for cardiorespiratory causes from 2007 to 2012. Indicators of PM10 sources; "volcanic ash", "dust storms", or "other sources" (traffic, fireworks, and re-suspension) on days when PM10 exceeded the daily air quality guideline value of 50 µg/m3 were entered into generalized additive models, adjusted for weather, time trend and co-pollutants. The average number of daily emergency hospital visits was 10.5. PM10 exceeded the air quality guideline value 115 out of 2191 days; 20 days due to volcanic ash, 14 due to dust storms (two days had both dust storm and ash contribution) and 83 due to other sources. High PM10 levels from volcanic ash tended to be significantly associated with the emergency hospital visits; estimates ranged from 4.8% (95% Confidence Interval (CI): 0.6, 9.2%) per day of exposure in unadjusted models to 7.3% (95% CI: -0.4, 15.5%) in adjusted models. Dust storms were not consistently associated with daily emergency hospital visits and other sources tended to show a negative association. We found some evidence indicating that volcanic ash particles were more harmful than particles from other sources, but the results were inconclusive and should be interpreted with caution.

In the aftermath of the Icelandic volcano Grimsvötn's eruption on 21 May 2011, volcanic ash reached Northern Europe. Elevated levels of ambient particles (PM) were registered in mid Sweden. The aim of the present study was to investigate if the Grimsvötn eruption had an effect on mortality in Sweden. Based on PM measurements at 16 sites across Sweden, data were classified into an ash exposed data set (Ash area) and an unexposed data set (No ash area). Data on daily all-cause mortality were obtained from Statistics Sweden for the time period 1 April through 31 July 2011. Mortality ratios were calculated as the ratio between the daily number of deaths in the Ash area and the No ash area. The exposure period was defined as the week following the days with elevated particle concentrations, namely 24 May through 31 May. The control period was defined as 1 April through 23 May and 1 June through 31 July. There was no absolute increase in mortality during the exposure period. However, during the exposure period the mean mortality ratio was 2.42 compared with 2.17 during the control period, implying a relatively higher number of deaths in the Ash area than in the No ash area. The differences in ratios were mostly due to a single day, 31 May, and were not statistically significant when tested with a Mann-Whitney non-parametric test (p > 0.3). The statistical power was low with only 8 days in the exposure period (24 May through 31 May). Assuming that the observed relative differences were not due to chance, the results would imply an increase of 128 deaths during the exposure period 24-31 May. If 31 May was excluded, the number of extra deaths was reduced to 20. The results of the present study are contradicting and inconclusive, but may indicate that all-cause mortality was increased by the ash-fall from the Grimsvötn eruption. Meta-analysis or pooled analysis of data from neighboring countries might make it possible to reach sufficient statistical power to study effects of the Grimsvötn ash on morbidity and mortality. Such studies would be of particular importance for European societies preparing for future large scale volcanic eruptions in Iceland.

Background: Air pollution exposure is associated with hospital admissions and emergency room visits for cardiopulmonary disease and stroke. Iceland's capital area, Reykjavik, has generally low air pollution levels, but traffic and natural sources contribute to pollution levels. The objective of this study was to investigate temporal associations between emergency hospital visits and air pollutants ozone (O3), nitrogen dioxide (NO2), and particulate matter (PM10) in the Icelandic capital area., Methods: We constructed a time series of the daily number of adults who visited the emergency room, or were acutely admitted for stroke or cardiorespiratory causes to Landspitali University Hospital 1 January 2003 - 31 December 2009 from the hospital in-patient register. We used generalized additive models assuming Poisson distribution, to analyze the daily emergency hospital visits as a function of the pollutant levels, and adjusted for meteorological variables, day of week, and time trend with splines., Results: Daily emergency hospital visits increased 3.9% (95% confidence interval (CI) 1.7-6.1%) per interquartile (IQR) change in average O3 the same and two previous days. For females, the increase was 7.8% (95% CI 3.6-12.1) for elderly (70+), the increase was 3.9% (95% CI 0.6-7.3%) per IQR increase of NO2. There were no associations with PM10., Conclusions: We found an increase in daily emergency hospital visits associated with O3, indicating that low-level exposure may trigger cardiopulmonary events or stroke.

Objectives: The study aimed to determine whether exposure to a volcanic eruption was associated with increased prevalence of physical and/or mental symptoms., Design: Cohort, with non-exposed control group., Setting: Natural disasters like volcanic eruptions constitute a major public-health threat. The Icelandic volcano Eyjafjallajökull exposed residents in southern Iceland to continuous ash fall for more than 5 weeks in spring 2010. This study was conducted during November 2010-March 2011, 6-9 months after the Eyjafjallajökull eruption., Participants: Adult (18-80 years of age) eruption-exposed South Icelanders (N=1148) and a control population of residents of Skagafjörður, North Iceland (N=510). The participation rate was 72%., Main Outcome Measures: Physical symptoms in the previous year (chronic), in the previous month (recent), General Health Questionnaire (GHQ-12) measured psychological morbidity., Results: The likelihood of having symptoms during the last month was higher in the exposed population, such as; tightness in the chest (OR 2.5; 95% CI 1.1 to 5.8), cough (OR 2.6; 95% CI 1.7 to 3.9), phlegm (OR 2.1; 95% CI 1.3 to 3.2), eye irritation (OR 2.9; 95% CI 2.0 to 4.1) and psychological morbidity symptoms (OR 1.3; 95% CI 1.0 to 1.7). Respiratory symptoms during the last 12 months were also more common in the exposed population; cough (OR 2.2; 95% CI 1.6 to 2.9), dyspnoea (OR 1.6; 95% CI 1.1 to 2.3), although the prevalence of underlying asthma and heart disease was similar. Twice as many in the exposed population had two or more symptoms from nose, eyes or upper-respiratory tract (24% vs 13%, p<0.001); these individuals were also more likely to experience psychological morbidity (OR 4.7; 95% CI 3.4 to 6.5) compared with individuals with no symptoms. Most symptoms exhibited a dose-response pattern within the exposed population, corresponding to low, medium and high exposure to the eruption., Conclusions: 6-9 months after the Eyjafjallajökull eruption, residents living in the exposed area, particularly those closest to the volcano, had markedly increased prevalence of various physical symptoms. A portion of the exposed population reported multiple symptoms and may be at risk for long-term physical and psychological morbidity. Studies of long-term consequences are therefore warranted.

Objective: To estimate physical and mental health effects of the Eyjafjallajökull volcanic eruption on nearby residents., Design: Cross-sectional study., Setting: The Icelandic volcano Eyjafjallajökull erupted on 14 April 2010. The eruption lasted for about 6 weeks and was explosive, ejecting some 8 million tons of fine particles into the atmosphere. Due to prevailing winds, the ash spread mostly to the south and south-east, first over the rural region to the south, later over the Atlantic Ocean and Europe, closing European air space for several days., Participants: Residents (n=207) of the most ash-exposed rural area south and east of the volcano., Methods: The study period was from 31 May to 11 June 2010. Participants were examined by a physician. To ascertain respiratory health, standardised spirometry was performed before and after the use of a bronchodilator. All adult participants answered questionnaires about mental and physical health, their children's health and the use of protective equipment., Results: Every other adult participant reported irritation in eyes and upper airway when exposed to volcanic ash. Adults (n=26) and children (n=5) with pre-existing asthma frequently reported worsening of their symptoms. No serious health problems requiring hospitalisation could be attributed to the eruption. The majority of the participants reported no abnormal physical or mental symptoms to the examining physician. Compared to an age- and gender-matched reference group, the ash-exposed participants reported lower smoking rates and were less likely to have ventilation impairment. Less than 10% of the participants reported symptoms of stress, anxiety or depression., Conclusions: Short-term ash exposure was associated with upper airway irritation symptoms and exacerbation of pre-existing asthma but did not contribute to serious health problems. The exposure did not impair respiratory function compared to controls. Outdoor use of protective glasses and face masks was considered protective against irritation in eyes and upper airway.

Background: Air pollutants in Iceland's capital area include hydrogen sulfide (H2S) emissions from geothermal power plants, particle pollution (PM10) and traffic-related pollutants. Respiratory health effects of exposure to PM and traffic pollutants are well documented, yet this is one of the first studies to investigate short-term health effects of ambient H2S exposure., Objectives: The aim of this study was to investigate the associations between daily ambient levels of H2S, PM10, nitrogen dioxide (NO2) and ozone (O3), and the use of drugs for obstructive pulmonary diseases in adults in Iceland's capital area., Methods: The study period was 8 March 2006 to 31 December 2009. We used log-linear Poisson generalized additive regression models with cubic splines to estimate relative risks of individually dispensed drugs by air pollution levels. A three-day moving average of the exposure variables gave the best fit to the data. Final models included significant covariates adjusting for climate and influenza epidemics, as well as time-dependent variables., Results: The three-day moving average of H2S and PM10 levels were positively associated with the number of individuals who were dispensed drugs at lag 3-5, corresponding to a 2.0% (95% confidence interval [CI] 0.4, 3.6) and 0.9% (95% CI 0.1, 1.8) per 10 μg/m3 pollutant concentration increase, respectively., Conclusion: Our findings indicated that intermittent increases in levels of particle matter from traffic and natural sources and ambient H2S levels were weakly associated with increased dispensing of drugs for obstructive pulmonary disease in Iceland's capital area. These weak associations could be confounded by unevaluated variables hence further studies are needed., (Copyright © 2012 Elsevier Inc. All rights reserved.)