Aims: To assess hazards associated with exposure to dust in the London Underground railway and to provide an informed opinion on the risks to workers and the travelling public of exposure to tunnel dust. Methods: Concentrations of dust, as mass (PM 2.5 ) and particle number, were measured at different underground stations and in train cabs; its size and composition were analysed; likely maximal exposures of staff and passengers were estimated; and in vitro toxicological testing of sample dusts in comparison with other dusts was performed. Results: Concentrations on station platforms were 270-480 mg/m 3 PM 2.5 and 14 000-29 000 particles/ cm 3 . Cab concentrations over a shift averaged 130-200 mg/m 3 and 17 000-23 000 particles/cm 3 . The dust comprised by mass approximately 67% iron oxide, 1-2% quartz, and traces of other metals, the residue being volatile matter. The finest particles are drawn underground from the surface while the coarser dust is generated by interaction of brakes, wheels, and rails. Taking account of durations of exposure, drivers and station staff would have maximum exposures of about 200 mg/m 3 over eight hours; the occupational exposure standard for welding fume, as iron oxide, is 5 mg/m 3 over an eight hour shift. Toxicology showed the dust to have cytotoxic and inflammatory potential at high doses, consistent with its composition largely of iron oxide. Discussion: It is unjustifiable to compare PM 2.5 exposure underground with that on the surface, since the adverse effects of iron oxide and combustion generated particles differ. Concentrations of ultrafine particles are lower and of coarser (PM 2.5 ) particles higher underground than on the surface. The concentrations underground are well below allowable workplace concentrations for iron oxide and unlikely to represent a significant cumulative risk to the health of workers or commuters.

Objectives-To investigate the hypothesis that chronic low level exposure to organophosphates (OPs) in sheep dips is related to clinically detectable measures of polyneuropathy. Methods-The design was a cross sectional exposure-response study of sheep dippers and other non-exposed groups. The study group consisted of 612 sheep dipping farmers, 53 farmers with no sheep dipping experience, and 107 ceramics workers. Retrospective exposure information was obtained by questionnaire based on stable and easily identifiable features of sheep dipping found during the first phase of the study; in particular, estimates of handling concentrate and splashing with dilute dip. Neurological assessments were based on a standard neuropathy symptoms questionnaire, and thermal and vibration quantitative sensory tests. Results-Adjusted for confounders there was a weak positive association between cumulative exposure to OPs and neurological symptoms, the significance of which was dependent on the inclusion of a few individual workers with extremely high exposure. There was no evidence of an association between cumulative exposure and the thermal or vibration sensory thresholds. However, separating the effects of exposure intensity and duration showed a higher prevalence of symptoms, primarily of a sensory type, among sheep dippers who handled the OP concentrate. There was also evidence that sensory and vibration thresholds were higher among concentrate handlers, the highest exposed group of dippers. Conclusions-The findings showed a strong association between exposure to OP concentrate and neurological symptoms, but a less consistent association with sensory thresholds. There was only weak evidence of a chronic eVect of low dose cumulative exposure to OPs. It is suggested that long term health eVects may occur in at least some sheep dippers exposed to OPs over a working life, although the mechanisms are unclear. (Occup Environ Med 2001;58:702-710)

There are limited data describing pollutant levels inside homes that burn solid fuel within developed country settings with most studies describing test conditions or the effect of interventions. This study recruited homes in Ireland and Scotland where open combustion processes take place. Open combustion was classified as coal, peat or wood fuel burning, use of a gas cooker or stove, or where there is at least one resident smoker. 24-hour data on airborne concentrations of particulate matter less than 2.5 microns in size (PM2.5), carbon monoxide (CO), endotoxin in inhalable dust and carbon dioxide (CO2), together with 2–3 week averaged concentrations of nitrogen dioxide (NO2) were collected in 100 houses during the winter and spring of 2009–2010. The geometric mean of the 24-hour time-weighted-average (TWA) PM2.5 concentration was highest in homes with resident smokers (99μg/m3 – much higher than the WHO 24-hour guidance value of 25 μg/m3. Lower geometric mean 24-hour TWA levels were found in homes that burned coal (7 μg/m3) or wood (6 μg/m3) and in homes with gas cookers (7 μg/m3). In peat-burning homes the average 24-hourPM2.5 level recorded was 11 μg/m3. Airborne endotoxin, CO, CO2 and NO2 concentrations were generally within indoor air quality guidance levels.

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Five physicians' radiological assessments of coalworkers' simple pneumoconiosis (CWP) in 2600 coalminers at 10 British collieries have been studied in relation to the individuals' estimated lifetime (mean 33 years) exposure to respirable coalmine dust. Estimates of exposure were based on 20 years of observations at each colliery. Radiographic classifications were clearly associated with the measures of dust exposure. Important unexplained differences between some of the collieries were disclosed. Among men with similar cumulative dust exposures those with longer exposure time had higher prevalence of CWP. In general there was no evidence that the quartz concentrations experienced (average 5 % of mixed dust) affected the probability of developing coalworkers' simple pneumoconiosis. Some men reacted unfavourably (two or more steps of change on the 12-point radiological scale) over a 10-year period to coalmine dust with a relatively high quartz content.Earlier reports from the National Coal Board's Pneumoconiosis Field Research have described an association between exposure to respirable coalmine dust and incidence of coalworkers' simple pneumoconiosis (CWP).1-5 The effect of quartz has also been studied.6 These were interim investigations, based on a 10-year period of observations of coalface workers at 20 British collieries. Results from a longer-term study at 10 collieries are presented in this paper, which has two main objectives. The first is to report new dust-related estimates of long-term incidence risks of pneumoconiosis among working miners. The second is to present further information on how the chances of developing CWP are influenced by the quartz content of the coalmine dust to which men are exposed. SubjectsSince 1953 medical surveys of the Pneumoconiosis Field Research have been carried out at roughly five-year intervals at selected collieries from all the major British coalfields. Ten collieries were surveyed at least five times. They cover a wide range of environmental and geological conditions. All currently employed miners were asked to take part on each occasion. This report considers primarily the 2600 men who attended the first, third, and fifth surveys at the 10 collieries, and for whom complete and reliable data were available. Men no longer in the industry were not studied: 8394 men, examined at these collieries at the first surveys, were alive and under 65 years old 20 years later. The 2600 long-term working miners studied form 31 % of that group. Some results are reported for a further 1730 men who attended the third and fifth surveys, but not the first, at these same collieries. Methods RADIOLOGICAL DATAEach of five physicians experienced in the radiology of pneumoconiosis classified the fifth survey fullsized (posteroanterior) chest radiographs of the men separately, independently, and in random order according to the ILO U/C International Classification of Radiographs of the Pneumoconioses,7 using 1968 standard films. Additionally, the readers classified all 4330 pairs of the third a...

A sample of men working in the British coal industry in the 1950s has been followed up and examined 22 years later. The relations between lung function and individual cumulative exposure to respirable dust have been studied in 1867 men who were still working in the industry at the time of follow up and 2192 men who had left. Levels of forced expired volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC ratio at follow up were found to be inversely related to exposure to respirable dust after allowing for other factors, even in men without pneumoconiosis. The magnitude of this estimated effect was equivalent to a loss of 228 ml FEV1 in response to an exposure of 300 gh/m3, a moderately high exposure for this group. Ex-miners aged under 65 had worse lung function than miners on average, suggesting that ill health had encouraged some of these men to leave the industry. Whereas a more severe response to dust exposure among ex-miners under 65 was suggested, this difference could easily have arisen by chance. The presence of symptoms of chronic bronchitis was associated with reduced levels of lung function, however, and, additionally, ex-miners under 65 with chronic bronchitis showed a more severe response of the FVC to dust exposure than miners without these symptoms. Among these ex-miners with chronic bronchitis a small group of men who had taken other jobs showed a much more severe effect of dust exposure on their lung function than the average, likely in heavily exposed men to contribute importantly to disability. Men in this group who had given up smoking showed an even more severe effect of dust exposure, equivalent to a loss of 940 ml FEV1 in response to an exposure of 300 gh/m3. These results indicate that exposure to respirable dust can occasionally cause severe respiratory impairment in the absence of progressive massive fibrosis. Dust exposure was related to a parallel reduction of FEV1 and FVC, implying that the pathology of dust induced lung damage differs from that induced by smoking. This pattern of abnormality was shown by some non-smokers, whereas smokers and ex-smokers apparently severely affected by dust showed a classic obstructive pattern of abnormality with pronounced reduction of the FEV1/FVC ratio. These studies were based on men still at work in the coal industry; and, since ill-health may influence some men to leave their work, it has not been clear whether Acoepted 17 June 1985 the quantitative dust/disease relation estimated applied to all miners generally, or whether some men who had left the industry had suffered greater response to dust exposure than had been observed in working miners.The first aim of the present study was to confirm the previous finding of a relation between exposure to respirable dust and level of lung function, using a more representative group of British miners, better measures of dust exposure and of smoking habits, and a wider range of lung function measurements than before. The second and main aim was to examine whether men who left t...

Objective: To examine changes in the health of bar workers after smoke-free legislation was introduced. Design: Longitudinal study following bar workers from before legislation introduction, at 2 months after introduction and at 1 year to control for seasonal differences. Setting: Bars across a range of socio-economic settings in Scotland. Participants: 371 bar workers recruited from 72 bars. Intervention: Introduction of smoke-free legislation prohibiting smoking in enclosed public places, including bars. Main outcomes measures: Change in prevalence of self-reported respiratory and sensory symptoms. Results: Of the 191 (51%) workers seen at 1-year followup, the percentage reporting any respiratory symptom fell from 69% to 57% (p = 0.02) and for sensory symptoms from 75% to 64% (p = 0.02) following reductions in exposure, effects being greater at 2 months, probably partly due to seasonal effects. Excluding respondents who reported having a cold at either baseline or 1 year, the reduction in respiratory symptoms was similar although greater for ''any'' sensory symptom (69% falling to 54%, p = 0.011). For non-smokers (n = 57) the reductions in reported symptoms were significant for phlegm production (32% to 14%, p = 0.011) and red/irritated eyes (44% to 18%, p = 0.001). Wheeze (48% to 31%, p = 0.006) and breathlessness (42% to 29%, p = 0.038) improved significantly in smokers. There was no relationship between change in salivary cotinine levels and change in symptoms. Conclusions: Bar workers in Scotland reported significantly fewer respiratory and sensory symptoms 1 year after their working environment became smoke free. As these improvements, controlled for seasonal variations, were seen in both non-smokers and smokers, smoke-free working environments may have potentially important benefits even for smokers.

Objectives To estimate the social costs of occupational asthma in the UK. Methods A desk-top approach using cost-of-illness methodology was employed, defining direct and indirect lifetime costs for six scenarios: a male and a female worker each exposed to isocyanates, latex and biocides (eg, glutaraldehyde) or flour. The numbers of new cases annually in each industry were estimated from Survey of Work-related and Occupational Respiratory Disease (SWORD) data. The main outcome measure was the current value total working lifetime costs of new cases annually for each scenario. Results Assuming 209 new cases of occupational asthma in the six scenarios in the year 2003, the present value total lifetime costs were estimated to be £25.3e27.3 million (2004 prices). Grossing up for all estimated cases of occupational asthma in the UK in 2003, this came to £70e100 million. About 49% of these costs were borne by the individual, 48% by the state and 3% by the employer. Conclusions The cost to society of occupational asthma in the UK is high. Given that the number of newly diagnosed cases is likely to be underestimated by at least one-third, these costs may be as large as £95e135 million. Each year a new stream of lifetime costs will be added as a newly diagnosed cohort is identified. Approaches to reduce the burden of occupational asthma have a strong economic justification. However, the economic burden falls on the state and the individual, not on the employer.