Science With Purpose: 50 Years of the Institute of Occupational Medicine.

The Institute of Occupational Medicine (IOM) was founded in 1969 by the then UK National Coal Board to complete its nation-wide epidemiological study of lung disease in coal miners, the Pneumoconiosis Field Research. The results quantified risks in the industry and were influential across the world in setting preventive standards. The research, based on epidemiology, was multidisciplinary from the start, and the IOM's broad scientific expertise was applied across many other industries with an increasing focus on environmental measurement and ergonomics. In 1990, as the coal industry declined, IOM became a self-funding research charity with a strong commercial arm. It has expanded its research, often with European collaborators and funding from governments, and has achieved wide recognition. This has most recently been applied during the pandemic in areas of hospital ventilation, personal protection, and viral exposure research, illustrating IOM's ability to respond to new environmental or occupational challenges.

Developing Pretend Play in Autistic Children Using the Playboxes Joint Play Approach as Part of Ongoing Practice.

A repeated measures single subject design was used to examine the effectiveness of a joint play approach embedded in professional practice, in supporting pretend play for autistic children. Seven autistic children, aged 5-8 years, with a placement within a specialist educational provision, and who demonstrated restricted play, participated in weekly sessions using the Playboxes approach over a period of 3 months. Pre- and post-approach pretend play abilities were assessed using the Symbolic Play Test and the Test of Pretend Play. Every child gained increased age-equivalent scores on the Test of Pretend Play, ranging from + 8 to + 30 months. Pretend Play abilities can support developmental outcomes and incorporation of this approach into regular practice could be of value for autistic children.

Exposure to Solar UV During Outdoor Construction Work in Britain.

Excessive exposure to ultraviolet (UV) radiation from the sun in summer can cause skin cancer and in Britain there are around 1500 new cases of non-melanoma skin cancer (NMSC) each year, caused by exposure to solar UV at work. Little is known about the magnitude of UV exposure amongst outdoor construction workers in Britain, although this is one of the main groups at risk. The aim of this paper is to summarise measurements of erythema-weighted UVB radiation amongst construction workers in Scotland and the Southeast of England and interpret the data in terms of the risk of NMSC. The measurements were made as part of an intervention study using short mobile phone text messages to alter worker behaviour to either reduce UV exposure in summer or increase serum vitamin D in winter; the intervention is only briefly reported here. Data were collected from 67 workers from 9 worksites, of whom 41 provided measures of UV exposure for 758 working days. Daily exposure ranged from 0 to 13.47 standard erythema dose (SED), with the mean exposure for outdoor workers being 2.0 SED and the corresponding value for indoor workers being 0.7 SED. These data were obtained from a sensor located on the back of the workers hard hat; others have measured exposure on the wrist or upper arm and these locations probably, on average, have higher levels of UV exposure. It is likely that an outdoor construction worker in Britain could accumulate sufficient solar UV exposure over 30-40 years of work to more than double their risk of NMSC. We argue that employers in Britain should take a more proactive approach to manage sun safety and they should take responsibility for skin health surveillance for their workers.

The relationship between personal exposure and ambient PM2.5 and black carbon in Beijing.

This study is part of the "Air Polluion Impacts on Cardiopulmonary disease in Beijing: an integrated study of Exposure Science, Toxicologenomics & Environmental Epidemiology (APIC-ESTEE)" project under the UK-China joint research programme "Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-China)". The aim is to capture the spatio-temporal variability in people's exposure to fine particles (PM2.5) and black carbon (BC) air pollution in Beijing, China. A total of 120 students were recruited for a panel study from ten universities in Haidian District in northwestern Beijing from December 2017 to June 2018. Real-time personal concentrations of PM2.5 and BC were measured over a 24-h period with two research-grade portable personal exposure monitors. Personal microenvironments (MEs) were determined by applying an algorithm to the handheld GPS unit data. On average, the participants spent the most time indoors (79% in Residence and 16% in Workplace), and much less time travelling by Walking, Cycling, Bus and Metro. Similar patterns were observed across participant gender and body-mass index classifications. The participants were exposed to 33.8 ± 27.8 µg m-3 PM2.5 and to 1.9 ± 1.2 µg m-3 BC over the 24-h monitoring period, on average 24.3 µg m-3 (42%) and 0.8 µg m-3 (28%) lower, respectively, than the concurrent fixed-site ambient measurements. Relative differences between personal and ambient BC concentrations showed greater variability across the MEs, highlighting significant contributions from Dining and travelling by Bus, which involve potential combustion of fuels. This study demonstrates the potential value of personal exposure monitoring in investigating air pollution related health effects, and in evaluating the effectiveness of pollution control and intervention measures.

Health Impact Assessment of Volcanic Ash Inhalation: A Comparison With Outdoor Air Pollution Methods.

This paper critically appraises the extrapolation of concentration-response functions (CRFs) for fine and coarse particulate matter, PM2.5 and PM10, respectively, used in outdoor air pollution health impact assessment (HIA) studies to assess the extent of health impacts in communities exposed to volcanic emissions. Treating volcanic ash as PM, we (1) consider existing models for HIA for general outdoor PM, (2) identify documented health effects from exposure to ash in volcanic eruptions, (3) discuss potential issues of applying CRFs based on the composition and concentration of ash-related PM, and (4) critically review available case studies of volcanic exposure scenarios utilizing HIA for outdoor air pollution. We identify a number of small-scale studies focusing on populations exposed to volcanic ash; exposure is rarely quantified, and there is limited evidence concerning the health effects of PM from volcanic eruptions. That limited evidence is, however, consistent with the CRFs typically used for outdoor air pollution HIA. Two health assessments of exposure to volcanic emissions have been published using population- and occupational-based CRFs, though each application entails distinct assumptions and limitations. We conclude that the best available strategy, at present, is to apply outdoor air pollution risk estimates to scenarios involving volcanic ash emissions for the purposes of HIA. However, due to the knowledge gaps on, for example, the health effects from exposure to volcanic ash and differences in ash composition, there is inherent uncertainty in this application. To conclude, we suggest actions to enable better prediction and assessment of health impacts of volcanic emissions.

Sun protection education for adolescents: a feasibility study of a wait-list controlled trial of an intervention involving a presentation, action planning, and SMS messages and using objective measurement of sun exposure.

BACKGROUND: People increase their risk of melanoma unless they are protected from the harmful effects of sun exposure during childhood and adolescence. We aimed to assess the feasibility of a three-component sun protection intervention- presentation, action planning, and SMS messages - and trial parameters. METHODS: This feasibility wait-list trial was conducted in the United Kingdom in 2018. Students aged 13-15 years were eligible. Feasibility outcomes were collected for recruitment rates; data availability rates for objective measurements of melanin and erythema using a Mexameter and self-reported sunburn occurrences, severity and body location, tanning, sun protection behaviours and Skin Self-Examination (SSE) collected before (baseline) and after the school summer holidays (follow-up); intervention reach, adherence, perceived impact and acceptability. Quantitative data were analysed using descriptive statistics; qualitative data were analysed thematically. RESULTS: Five out of eight schools expressing an interest in participating with four allocated to act as intervention and one control. Four parents/carers opted their child out of the study. Four hundred and eighty-seven out of 724 students on the school register consented to the study at baseline (67%). Three hundred and eighty-five were in intervention group schools. Objective skin measurements were available for 255 (66%) of the intervention group at baseline and 237 (61%) of the group at follow up. Melanin increased; erythema decreased. Complete self-report data were available for 247 (64%) students in the intervention group. The number of students on the school register who attended the presentation and given the booklet was 379 (98%) and gave their mobile phone number was 155 (40%). No intervention component was perceived as more impactful on sun protection behaviours. Adolescents did not see the relevance of sun protection in the UK or for their age group. CONCLUSIONS: This is the first study to use a Mexameter to measure skin colour in adolescents. Erythema (visible redness) lasts no more than three days and its measurement before and after a six week summer holiday may not yield relevant or meaningful data. A major challenge is that adolescents do not see the relevance of sun protection and SSE. TRIAL REGISTRATION: International Standard Randomised Controlled Trial Number ISRCTN11141528. Date registered 0/2/03/2018; last edited 31/05/2018. Retrospectively registered.

Occupational Exposures in an Equestrian Centre to Respirable Dust and Respirable Crystalline Silica.

Sand-based products are regularly used as footing material on indoor equestrian arenas, creating a potential occupational exposure risk for respirable crystalline silica (RCS) for equestrian workers training and exercising horses in these environments. The objective of this study was to evaluate an equestrian worker's personal RCS and respirable dust (RD) exposure. Sixteen personal full-shift RD measurements were collected from an equestrian worker and analysed for RD, quartz and cristobalite. Geometric mean exposures of 0.12 mg m-3 and 0.02 mg m-3 were calculated for RD and RCS concentrations, respectively. RCS exposures of between 0.01 to 0.09 mg m-3 were measured on days when the indoor arena surface was not watered, compared to lower exposures (

Effectiveness of face masks used to protect Beijing residents against particulate air pollution.

OBJECTIVES: Many residents in Beijing use disposable face masks in an attempt to protect their health from high particulate matter (PM) concentrations. Retail masks may be certified to local or international standards, but their real-life performance may not confer the exposure reduction potential that is marketed. This study aimed to evaluate the effectiveness of a range of face masks that are commercially available in China. METHODS: Nine masks claiming protection against fine PM (PM2.5) were purchased from consumer outlets in Beijing. The masks' filtration efficiency was tested by drawing airborne diesel exhaust through a section of the material and measuring the PM2.5 and black carbon (BC) concentrations upstream and downstream of the filtering medium. Four masks were selected for testing on volunteers. Volunteers were exposed to diesel exhaust inside an experimental chamber while performing sedentary tasks and active tasks. BC concentrations were continuously monitored inside and outside the mask. RESULTS: The mean per cent penetration for each mask material ranged from 0.26% to 29%, depending on the flow rate and mask material. In the volunteer tests, the average total inward leakage (TIL) of BC ranged from 3% to 68% in the sedentary tests and from 7% to 66% in the active tests. Only one mask type tested showed an average TIL of less than 10%, under both test conditions. CONCLUSIONS: Many commercially available face masks may not provide adequate protection, primarily due to poor facial fit. Our results indicate that further attention should be given to mask design and providing evidence-based guidance to consumers.

A randomised control crossover trial of a theory based intervention to improve sun-safe and healthy behaviours in construction workers: study protocol.

BACKGROUND: Exposure to sunlight can have both positive and negative health impacts. Excessive exposure to ultra-violet (UV) radiation from the sun can cause skin cancer, however insufficient exposure to sunlight has a detrimental effect on production of Vitamin D. In the construction industry there are onsite proactive behaviours for safety, but sun-safety remains a low priority. There is limited research on understanding the barriers to adopting sun-safe behaviours and the association this may have with Vitamin D production. This paper reports a protocol for an intervention study, using text messaging in combination with a supportive smartphone App. The intervention aims to both reduce UV exposure during months with higher UV levels and promote appropriate dietary changes to boost Vitamin D levels during months with low UV levels. METHOD/DESIGN: Approximately 60 construction workers will be recruited across the United Kingdom. A randomised control crossover trial (RCCT) will be used to test the intervention, with randomisation at site level - i.e. participants will receive both the control (no text messages or supportive App support) and intervention (daily text messages and supportive App). Using the Theory of Planned Behaviour (TPB) the intervention focuses on supporting sun-safety and healthy dietary decisions in relation to Vitamin D intake. The intervention emphasises cultivating the perception of normative support in the workplace, increasing awareness of control and self-efficacy in taking sun-protective behaviours, making healthier eating choices to boost Vitamin D, and tackling stigmas attached to image and group norms. Each study epoch will last 21 days with intervention text messages delivered on workdays only. The supportive App will provide supplementary information about sun protective behaviours and healthy dietary choices. The primary outcome measure is 25-hydroxy-Vitamin D [25(OH)D] level (obtained using blood spot sampling), which will be taken pre and post control and intervention periods. Secondary outcome measures are two-fold, (1) using the TPB to detect changes in behaviour, and (2) quantifying UV exposure during the UK peak radiation season (April-September) using body-mounted UV sensors. DISCUSSION: This study will provide important information about the effectiveness of a technology-based intervention to promote sun-safety and healthy behaviours in outdoor construction workers. TRIAL REGISTRATION: ISRCTN15888934 retrospectively registered 15.01.2018.

Mortality Among Hardmetal Production Workers: UK Cohort and Nested Case-Control Studies.

OBJECTIVE: The aim of this study was to characterize the mortality at two hardmetal production factories in the United Kingdom as part of an international study. METHODS: Standardized mortality ratios (SMRs) were calculated on the basis of mortality rates for England and Wales, and local rates. A nested case-control study of lung cancer was undertaken. RESULTS: The cohort comprised 1538 workers, with tracing complete for 94.4%. All-cause mortality was statistically significantly low for all cancers and nonmalignant respiratory disease, and for lung cancer was nonsignificantly low. The SMR for lung cancer for maintenance workers was elevated, based on only six deaths. The odds ratio for lung cancer per year of exposure to hardmetal was 0.93 (0.76 to 1.13). CONCLUSIONS: In this small study, there is no evidence to support that working in the UK hardmetal manufacturing industry increased mortality from any cause including lung cancer.

Health impact assessment of transport policies in Rotterdam: Decrease of total traffic and increase of electric car use.

BACKGROUND: Green house gas (GHG) mitigation policies can be evaluated by showing their co-benefits to health. METHOD: Health Impact Assessment (HIA) was used to quantify co-benefits of GHG mitigation policies in Rotterdam. The effects of two separate interventions (10% reduction of private vehicle kilometers and a share of 50% electric-powered private vehicle kilometers) on particulate matter (PM2.5), elemental carbon (EC) and noise (engine noise and tyre noise) were assessed using Years of Life Lost (YLL) and Years Lived with Disability (YLD). The baseline was 2010 and the end of the assessment 2020. RESULTS: The intervention aimed at reducing traffic is associated with a decreased exposure to noise resulting in a reduction of 21 (confidence interval (CI): 11-129) YLDs due to annoyance and 35 (CI: 20-51) YLDs due to sleep disturbance for the population per year. The effects of 50% electric-powered car use are slightly higher with a reduction of 26 (CI: 13-116) and 41 (CI: 24-60) YLDs, respectively. The two interventions have marginal effects on air pollution, because already implemented traffic policies will reduce PM2.5 and EC by around 40% and 60% respectively, from 2010 to 2020. DISCUSSION: The evaluation of planned interventions, related to climate change policies, targeting only the transport sector can result in small co-benefits for health, if the analysis is limited to air pollution and noise. This urges to expand the analysis by including other impacts, e.g. physical activity and well-being, as a necessary step to better understanding consequences of interventions and carefully orienting resources useful to build knowledge to improve public health.

Inadvertent ingestion exposure: hand- and object-to-mouth behavior among workers.

Contact between contaminated hands and the mouth or the area around the mouth (the perioral area) can result in inadvertent ingestion exposure. Exposure by this route is known to occur among children, but adults may also be exposed. Observations of 48 workers were carried out in 8 UK worksites to study hand- and object-to-mouth behavior. Each subject was observed in real-time for ~60 min during normal work activities. Each contact was recorded along with information about time of contact, glove use, respirator use, task and object type. Subjects were interviewed to gather information about smoking, nail biting and risk perception. The effects of factors (glove use, respirator use, smoking, nail biting, risk perception, work sector and task group) on contact frequency were assessed using non-parametric tests and Poisson regression models. Several determinants of contact frequency were identified, including time spent "between" work tasks, glove and respirator use, smoking and nail biting. Hand-to-mouth contact frequencies were particularly high while workers were "between" work tasks (23.6 contacts per hour, compared with the average contact frequency of 6.3 per hour). The factors that were related to contact frequency differed between object- and hand-to-mouth contacts, suggesting that these should be considered separately. These findings could be used for developing exposure models, to inform measurements of inadvertent ingestion among adults and to identify control strategies.

Multi-walled carbon nanotube induced frustrated phagocytosis, cytotoxicity and pro-inflammatory conditions in macrophages are length dependent and greater than that of asbestos.

The potential toxicity of carbon nanotubes (CNTs) has been compared to pathogenic fibres such as asbestos. It is important to test this hypothesis to ascertain safe methods for CNT production, handling and disposal. In this study aspects reported to contribute to CNT toxicity were assessed: length, aspect ratio, iron content and crystallinity; with responses compared to industrially produced MWCNTs and toxicologically relevant materials such as asbestos. The impacts of these particles on a range of macrophage models in vitro were assessed due to the key role of macrophages in particle clearance and particle/fibre-induced disease. Industrially produced and long MWCNTs were cytotoxic to cells, and were potent in inducing pro-inflammatory and pro-fibrotic immune responses. Short CNTs did not induce any cytotoxicity. Frustrated phagocytosis was most evident in response to long CNTs, as was respiratory burst and reduction in phagocytic ability. Short CNTs, metal content and crystallinity had less or no influence on these endpoints, suggesting that many responses were fibre-length dependent. This study demonstrates that CNTs are potentially pathogenic, as they were routinely found to induce detrimental responses in macrophages greater than those induced by asbestos at the same mass-based dose.

Suitability of human and mammalian cells of different origin for the assessment of genotoxicity of metal and polymeric engineered nanoparticles.

Nanogenotoxicity is a crucial endpoint in safety testing of nanomaterials as it addresses potential mutagenicity, which has implications for risks of both genetic disease and carcinogenesis. Within the NanoTEST project, we investigated the genotoxic potential of well-characterised nanoparticles (NPs): titanium dioxide (TiO2) NPs of nominal size 20 nm, iron oxide (8 nm) both uncoated (U-Fe3O4) and oleic acid coated (OC-Fe3O4), rhodamine-labelled amorphous silica 25 (Fl-25 SiO2) and 50 nm (Fl-50 SiO) and polylactic glycolic acid polyethylene oxide polymeric NPs - as well as Endorem® as a negative control for detection of strand breaks and oxidised DNA lesions with the alkaline comet assay. Using primary cells and cell lines derived from blood (human lymphocytes and lymphoblastoid TK6 cells), vascular/central nervous system (human endothelial human cerebral endothelial cells), liver (rat hepatocytes and Kupffer cells), kidney (monkey Cos-1 and human HEK293 cells), lung (human bronchial 16HBE14o cells) and placenta (human BeWo b30), we were interested in which in vitro cell model is sufficient to detect positive (genotoxic) and negative (non-genotoxic) responses. All in vitro studies were harmonized, i.e. NPs from the same batch, and identical dispersion protocols (for TiO2 NPs, two dispersions were used), exposure time, concentration range, culture conditions and time-courses were used. The results from the statistical evaluation show that OC-Fe3O4 and TiO2 NPs are genotoxic in the experimental conditions used. When all NPs were included in the analysis, no differences were seen among cell lines - demonstrating the usefulness of the assay in all cells to identify genotoxic and non-genotoxic NPs. The TK6 cells, human lymphocytes, BeWo b30 and kidney cells seem to be the most reliable for detecting a dose-response.

Is pesticide exposure a cause of obstructive airways disease?

A systematic review was performed to identify any associations between pesticide exposure and the occurrence (both prevalence and incidence) of airways disease (asthma and chronic obstructive pulmonary disease) and wheezing symptoms. PubMed, MEDLINE, Embase, Scopus, CINAHL, Google Scholar and the Cochrane Database of Systematic Reviews were searched between September 2010 and October 2010 for papers with the inclusion criteria of English language, published after 1990, peer-reviewed and nondietary exposure. From a total of 4390 papers identified, 42 were included after initial assessment of content. After evaluating the included studies for quality, those considered to be at high risk of bias were excluded, leaving a total of 23 relevant papers. Results suggest that exposure to pesticides may be associated with prevalent asthma, but methodological issues, such as cross-sectional/case-control design, measurements of exposure and limited adjustment for confounders, limit the strength of the evidence base in this area. The association between pesticide exposure and asthma appears to be more evident and consistent in children than in adults. Exposure to pesticides may be associated with COPD; however, the strength of evidence for an association with COPD is weaker than for asthma. As the exposure metrics within each health end-point varied across studies, no meta-analyses were carried out.

Associations between environmental exposures and asthma control and exacerbations in young children: a systematic review.

OBJECTIVE: To complete a systematic review of the literature describing associations between all environmental exposures and asthma symptoms and exacerbations in children up to mean age of 9 years. DESIGN: Systematic review. SETTING: Reference lists of identified studies and reviews were searched for all articles published until November 2013 in electronic databases (MEDLINE, EMBASE, CINAHL, Cochrane Controls Trials Register). PARTICIPANTS: Studies were selected which examined a link between exposure to environmental factors and asthma symptoms and exacerbations where the study participants were children with a mean age of ≤9 years. PRIMARY AND SECONDARY OUTCOME MEASURES: Indices of asthma symptoms, control and exacerbations. RESULTS: A total of 27 studies were identified including eight where inhaled allergens and four where environmental tobacco smoke (ETS) were the exposures of interest. There was evidence that exposure to allergen, ETS, poor air quality and unflued heaters had a modest magnitude of effect (ORs between 2 and 3). There was also evidence of interactions observed between exposures such as allergen and ETS. CONCLUSIONS: Exposure to inhaled allergens, ETS, unflued heaters and poor air quality has an important effect on exacerbations in young children with asthma and should be minimised or, ideally, avoided. Better understanding of the effect of exposure to damp housing, air conditioning and dietary factors plus interactions between environmental exposures associated with exacerbations is required.

A preliminary comparison of three dermal exposure sampling methods: rinses, wipes and cotton gloves.

Several methods exist to estimate dermal exposure and it is unclear how comparable they are. These methods fall into three main categories: (i) removal techniques (such as wiping or rinsing); (ii) interception techniques (such as gloves, patches, or coveralls); and (iii) fluorescent tracer techniques. Controlled experiments were conducted to compare two removal methods for exposure to particulate, and a removal method with an interception method for exposure to liquids. Volunteers' hands were exposed to three liquid solutions (glycerol-water solutions of different concentrations) and three particulates (Epsom salts, calcium acetate and zinc oxide) in simulated exposure scenarios. Both hands were exposed and a different sampling method was used on each to allow comparison of methods. Cotton glove samplers and a cotton wipe sampling method were compared for exposure to liquids. For exposure to powders a cotton wipe sampling method was compared to rinsing the hands in deionised water. Wipe and rinse methods generally yielded similar results for Epsom salts and zinc oxide (geometric mean [GM] ratios of wipe-to-rinse measurements of 0.6 and 1.4, respectively) but they did not for calcium acetate (GM wipe-to-rinse ratio of 4.6). For glycerol solutions measurements from the glove samplers were consistently higher than wipe samples. At lower levels of exposure the relative difference between the two methods was greater than at higher levels. At a hand loading level of 24,000 µg cm(-2) (as measured by wiping) the glove-to-wipe ratio was 1.4 and at a hand loading of 0.09 µg cm(-2) the ratio was 42.0. Wipe and rinse methods may be directly comparable but the relationship between glove and wipe sampling methods appears to be complex. Further research is necessary to enable conversion of exposure measurements from one metric to another, so as to facilitate more reliable risk assessment.

Using PM2.5 concentrations to estimate the health burden from solid fuel combustion, with application to Irish and Scottish homes.

BACKGROUND: This study estimates the potential population health burden from exposure to combustion-derived particulate air pollution in domestic settings in Ireland and Scotland. METHODS: The study focused on solid fuel combustion used for heating and the use of gas for cooking. PM2.5 (particulate matter with an aerodynamic diameter < 2.5 µm) was used as the pollutant mixture indicator. Measured PM2.5 concentrations in homes using solid fuels were adjusted for other sources of PM2.5 by subtracting PM2.5 concentrations in homes using gas for cooking but not solid fuel heating. Health burden was estimated for exposure indoors 6 pm - midnight, or all day (24-hour), by combining estimated attributable annual PM2.5 exposures with (i) selected epidemiological functions linking PM2.5 with mortality and morbidity (involving some re-scaling from PM10 to PM2.5, and adjustments 'translating' from concentrations to exposures) and (ii) on the current population exposed and background rates of morbidity and mortality. RESULTS: PM2.5 concentrations in coal and wood burning homes were similar to homes using gas for cooking, used here as a baseline (mean 24-hr PM2.5 concentrations 8.6 µg/m3) and so health impacts were not calculated. Concentrations of PM2.5 in homes using peat were higher (24-hr mean 15.6 µg/m3); however, health impacts were calculated for the exposed population in Ireland only; the proportion exposed in Scotland was very small. The assessment for winter evening exposure (estimated annual average increase of 2.11 µg/m3 over baseline) estimated 21 additional annual cases of all-cause mortality, 55 of chronic bronchitis, and 30,100 and 38,000 annual lower respiratory symptom days (including cough) and restricted activity days respectively. CONCLUSION: New methods for estimating the potential health burden of combustion-generated pollution from solid fuels in Irish and Scottish homes are provided. The methodology involves several approximations and uncertainties but is consistent with a wider movement towards quantifying risks in PM2.5 irrespective of source. Results show an effect of indoor smoke from using peat (but not wood or coal) for heating and cooking; but they do not suggest that this is a major public health issue.