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INSIDE
EXPOSURE MAGAZINE 3 Welcome 4 President’s Column 5 CEO’s Column 6 Meet the Member - Adrian Sims 8 Annals of Work Exposures and Health: 2019 Performance and Activity 12 History of Occupational Hygiene - part 8 16 Something Smells in Here!
Welcome Happy (belated) New Year, and welcome to Exposure Magazine’s first issue of 2020!
We hope you had a very Merry Christmas and an even happier New Year, and have gotten off to a great start through January and February. January always manages to feel like a 6-week month as we settle back into work and start on those resolutions! But now, on to the content of this fabulous 2020 kickstarter. Inside this issue, Trevor Ogden delivers part 8 of his ‘History of British Occupational Hygiene’ series, where he delves into the problem of coal-worker pneumoconiosis, and how tackling this had a big effect on measurement methods for other particulates. On page 8 is our yearly Annals of Work Exposures and Health Review, where Dr. Noah Seixas reports on the journal’s performance and activity during 2019. As he enters his last year as Chief Editor, Noah also penned a few words about his time leading the journal. It is also with great sadness that we say goodbye to Steve Beckett in January, a key BOHS member in the 1970’s, co-designer of the Walton-Beckett microscope graticule for asbestos, and conductor of a number of studies which, led in the end, to the RICE scheme. On page 22, Trevor Ogden has written a touching obituary to celebrate and commemorate the tremendous work Steve did within the field of Occupational Hygiene. We wish his family all the best during this difficult time.
20 Do you want to write for Exposure? 22 Graticules and Chocolate: Stephen Beckett’s legacy
There’s a lot to be getting involved with this year, so if you have any questions or feedback for us, please get in touch at exposure@bohs.org. We’ll see you next issue, where we’ll be talking all things OH2020, we anticipate we’ll see a lot of you there, and not just at the bar!
THE EXPOSURE TEAM LEE BURKETT
EVI KARMOU
JOE MOTT
LATEST BOHS NEWS & INFO @BOHS BOHS Head Office 5/6 Melbourne Business Court, Millennium Way, Pride Park, Derby, DE24 8LZ, UK T: + 44 (0) 1332 298101 | membership@bohs.org | www.bohs.org The views expressed in this issue are not necessarily those of BOHS Board
EXPOSURE #1 FEBRUARY 2020 - the official magazine of BOHS
@BOHSworld @BOHS Video @BOHSworld
3
PRESIDENT’S COLUMN
Hello everyone – in my last column I started by saying “we are well into the first throes of Winter now” and went on to suggest we may well have a potentially harsh Winter! Head of Qualifications & Training), her partner Mark, and myself were also part of the BOHS contingent for the 3M Fancy Dress Dinner, on the subject of recycle, reuse or re-purpose.
JOHN DOBBIE BOHS PRESIDENT
Well so far, I was a long way off the mark – with it remaining very wet, but unseasonably mild. I wrote that column from Perth in Australia, where I was attending the annual AIOH Conference, this was before the devastating fires that we have seen in many parts of the country, resulting in the horrific loss of lives and livelihoods. My heart goes out to everyone who suffered in any way from the fires or their aftermath and I am sure you will join me in hoping they recover and rebuild as quickly as possible. I mentioned too, that Lisa Williams (our
I am sad to report we didn’t win, but there was a very strong field of competitors – who in some cases, at least from my perspective, were only very tenuously linked to the theme of recycle, reuse or re-purpose. I still maintain we didn’t get the recognition we deserved, but that may be a character flaw in that I never like losing to the Aussies! Another good thing to come out of the AIOH Conference was the chance to build on our colloboration on Breathe Freely. The AIOH are not only implementing it very effectively, but we discovered that some of their learnings will be useful to us too. There was also interest from the New Zealand Occupational Hygiene Society in adopting Breathe Freely, which is now actively being looked at.
Many of you will have heard the sad news that our CEO, Simon Festing, has elected to leave the Society, owing to the challenges of balancing his work against his family life, exarcebated by needing to travel between a flat in Derby and his home in London. We fully understand his position and I know he will be greatly missed, and we wish him well for his future ventures. Simon joined BOHS at a time when the Society had ambitious plans to raise the profile of occupational hygiene and had embarked upon the Breathe freely campaigns, which had great success in heightening our external presence. To respond to this rapid progress both the head office staff and the Board (then, the Council) had increased their efforts and workload to meet the technical challenges, but had possibly drifted a little in terms of governance and internal processes. Simon rapidly managed to address both these areas with significant success. He leaves BOHS in a much better place than it was when he started. I wish Simon every success in the future and thank him for all his effort over the past two years.
I am hopeful that we will be successful in recruiting a great CEO, who will continue in the task of building the BOHS into a progressive, outgoing, and successful professional body.
4
BOHS.ORG
CEO’S COLUMN
This is my last editorial as CEO of the Society – a role which I have very much enjoyed over the last couple of years. SIMON FESTING CHIEF EXECUTIVE OFFICER
I’d like to remind all readers of Exposure magazine that the involvement of active members is the lifeblood of the Society. Staff can run the machinery of the Society, but ultimately it’s the expertise of the members which progresses the work. Please do look out for opportunities for getting involved. Volunteer opportunities are regularly posted on our website.
These years have seen some consolidation at Head Office, as we have sought to modernise the systems of the Society. The next stage of this should be a much-improved website, due midsummer. Hopefully this will allow a considerably more streamlined and appealing service to members, with richer and better content. This internal modernisation of the Society has been achieved with substantial financial investment. The Board of Trustees have deliberated carefully over the short and medium-term spending
I’m confident that the Society continues to be in good shape, and should be able to react to the challenges ahead. plans of the Society. We are pleased to see that even with the additional expenditure, and an expansion of staff numbers, during 2019 we still managed to break even in terms of our income and expenditure. Investment returns have been positive as well, allowing the Society to maintain a good level of reserves for continued investment. A number of areas of the Society have demonstrated sustained growth in recent years, and in particular our qualifications are achieving robust results. And our journal (Annals of Work Exposures and Health) continues to be financially strong, as the second largest contributor to our net revenues. Following a retender exercise in the second half of the year, Oxford University Press was successfully reappointed as publisher of the journal for an additional five years from 2020. All of this means I will be able to hand over the reins of the Society while it is in good financial health! There is, of course, still plenty of outwardfacing activity going on. We have just launched a new round of Breathe Freely in Manufacturing Roadshows. We are looking for new ways to evolve this highly successful campaign, and continue to engage with partners and collaborators in a myriad of ways. Meanwhile, we are gearing up for what we hope will be a highly successful OH2020 conference in Bristol towards the end of April, which I very much hope you will be able to attend.
EXPOSURE #1 FEBRUARY 2020 - the official magazine of BOHS
We have new initiatives coming through in membership, such as the launch of a mentoring platform, which should help to address the needs of early-career occupational hygienist. All of the activities of the Society are held together by the strategic plan, which is compiled by the CEO in consultation with key stakeholders, and then adopted and owned by the Board. We are in the process of developing a new strategic plan to start in 2021, which will supersede the existing plan, now in its final year. The new strategic plan is already at the late draft stage, but will be kept open for some months into 2020 to allow an incoming CEO to review. The Board will give a progress update at the annual conference, and then approve the plan later in the year.
May I wish the Trustees and the members of the Society all the best in continuing to improve worker health protection in the years ahead.
5
MEET THE MEMBER
ADRIAN SIMS FOH SPECIALIST MEMBER
Q WHAT LED YOU TO
PURSUE YOUR CURRENT PROFESSION?
A Fate. My father is an
engineer and I used to watch him do technical drawings at home. I thought that looks good so left school and trained to become a building services engineer. After several job moves I ended up working for a centrifugal fan manufacture who did installations of LEV systems. They made me redundant in 2001. I started Vent-Tech working closely with industry manufactures, supplying and installing LEV. It was only by chance that I came across a BOHS conference being held in Norwich back in 2005 (I think) talking about HSG258 which I attended and met Alvin Wooley and Andy Gillies. After talking to Andy, the long drive back led to a bit of ‘blue sky’ thinking about the direction both Vent-Tech and myself were moving in. It was after this that I met Bill Cassells and we did the very first P602 LEV Design course together.
Q WHY DID YOU
BECOME A MEMBER OF BOHS?
A Following the conference
in Norwich, it seemed the right thing to do. BOHS is an organization that is striving to make a difference to people’s wellbeing. As an LEV engineer I have the same goals.
Q WHAT ASPECT OF
YOUR BOHS MEMBERSHIP DO YOU VALUE THE MOST?
A The networking with likeminded people.
Q HOW HAVE THE BOHS QUALIFICATIONS HELPED YOU IN YOUR CAREER?
They have helped me gain a basic understanding of the principles of LEV and occupational hygiene. Together with my building services engineering degree they help me fully understand how LEV works and more importantly is used.
Q
HOW HAVE THE BOHS CONFERENCES BEEN VALUABLE TO YOU THROUGH YOUR CAREER?
A As above, they are a
great place to network and share knowledge.
Q
WHAT DO YOU ENJOY MOST ABOUT OUR PUBLICATIONS (ANNALS OF WORK EXPOSURE AND HEALTH, EXPOSURE, FAAM NEWS, E-BULLETINS, WEBSITE NEWS)?
A They help me keep up
to date with the latest thinking in the industry. Not all of it is relevant to what I do but it is a great resource.
Q
WHAT DO YOU THINK ABOUT THE ROLE BOHS IS PLAYING IN PROMOTING WORKER HEALTH PROTECTION?
A Education and
awareness (if these are not the same thing). The biggest challenge we face is educating people as to the how and who should use them? The BOHS has the ability to position the right people in front of the right audiences to make this happen.
Q
WHAT ADVICE WOULD YOU GIVE TO YOUR YOUNGER SELF, OR THOSE ENTERING THE PROFESSION?
However, this comes with a health warning. There is also a lot of poor information out there.
Q
AWAY FROM YOUR PROFESSIONAL LIFE, WHAT HOBBIES AND INTERESTS DO YOU HAVE?
A I have always done a lot of sport including canoeing, climbing and in later years I started playing rugby.
I try and keep fit and play 5 aside twice a week but I have reached a physical peak now where this is rapidly becoming walking football! Many of the people I play with would describe it more as just walking.
A Read more. There is a
wealth of information out there available at our fingertips. When I was younger the internet was not what it is today so we were limited to the books in the local library however now there are articles, blogs, webinars, videos etc. and all sorts of good information available online.
WANT TO BE OUR NEXT EXPOSURE STAR? Contact us at exposure@bohs.org to find out how! 6
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The Chartered Society for Worker Health Protection
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ANNALS OF WORK - 2019 REVIEW
ANNALS OF WORK EXPOSURES AND HEALTH: 2019 PERFORMANCE AND ACTIVITY
NOAH SEIXAS
ACTIVITY AND PRODUCT
I am pleased to report to the BOHS membership that we have now fully edited, printed, and distributed worldwide Volume 63 of the Annals of Work Exposures and Health. The volume continues to offer readers and scientists a wide range of investigations of working conditions and their impact on the health of those doing the work. This is the third complete volume under the name Annals of Work Exposures and Health, demonstrating our attention to the myriad conditions which are intended by the concept of ‘exposure’, and the wide range of impacts on health and well-being or working people. We believe the content and impact of the journal reflects this broadening perspective.
In 2019 we published nine issues, 80 original articles, 7 editorials, 5 commentaries, 4 short communications, 2 letters to the editor, and 1 review. Of the 250 submissions during the year, 191 were original research articles, 21 short communications, 19 reviews, 8 editorials, 7 commentaries, and 4 letters to the editor. Among the 225 articles for which final publication decisions were made, 86 were accepted, giving us a rejection rate of 61.8%.
8
Notable accomplishments included the publication in July of a special issue relating to X2018, the 9th International Conference on the Science of Exposure Assessment (issue #6). With excellent leadership from the two guest editors, Kate Jones and Martie van Tongeren,
we solicited contributions from keynote speakers and other conference presenters, resulting in 3 editorials, 2 commentaries, 6 original articles and 1 short communication. We have again looked at the distribution of types of studies and hazards addressed in our published papers. Exposure assessment continues as our predominant type of study (44%) although this category is very broadly defined. Ten percent of our papers are epidemiologic in nature and an increased number of studies addressed measurement methods, 21% up from 10% the previous year. We also increased our presentation of sciences underlying the methods used for exposure assessment and control. We had a similar number of articles compared to last year addressing aerosol exposures (20%),
BOHS.ORG
chemicals (28%), psychosocial conditions (7%), and an increase in physical agents, up to 13%. Published articles continue to be from first authors in North America (37%), Europe (outside of the UK, 25%) and Scandinavia (15%) with 6% from the UK, and smaller numbers from Australasia (6%), East Asia (5%) and other countries (6%). The editorial team coordinated the collection of 466 peer reviews from 306 individuals— fewer reviews but more individual reviewers than the previous year. Our time for articles in review has been monitored using a 6-month running average, giving the average (median) time to a first decision of 38 (32) days, while time to reach a final decision (after revision and re-review) was 91 (44) days (based on July to December). Due to the way it is measured, the Annals journal impact factor (JIF) is still being affected by the journal’s name change, although early indications of progress are encouraging. Our JIF for 2018 was 1.713, an increase from 1.615 in 2017; however, this is a combined JIF based on data from the old and new journal, and we must wait until the 2019 JIF is published for a JIF based entirely on the new journal.
During the last year 2,966 institutions were able to access the journal either via a direct institutional subscription or through academic consortia agreements. More than 7,000 notfor-profit institutions in developing countries have potential access through the developing countries scheme. The average number of full-text downloads per month was 35,643, a 2.6% increase on 2018.
as the publisher of the Annals. OUP provides a range of services in support of the journal including peer review system software, typesetting and copy-editing, printing and distribution, and website maintenance and marketing. The editor responsible for the Annals is Paul Kidd, who is supported by Katie Kent in Production, and Emma Horton in Marketing.
STAFF AND MANAGEMENT
PAPER-FREE PUBLICATION
Our Editorial Board remained the same in 2019; the team of 13 Assistant Editors and three additional Board members continued to work hard to develop high quality and relevant papers for the journal.
You may remember that in the June 2019 issue of Exposure magazine, we explained why and how we would be encouraging a move to paper-free publication. As of 1 January 2020, we introduced a surcharge of £40 to cover costs for BOHS members who wish to receive the print edition. We see this as the fairest way to facilitate online access while giving those who value the print edition the opportunity to retain it. By supporting us in this initiative our members are helping BOHS to reduce its carbon footprint and the print-related costs, and we hope that more and more of you will discover the benefits of the digital version in the coming months. Although it is still early days, the response so far has been very encouraging, and we will keep you updated on progress. Thank you for your support.
Some changes took place within the editorial support team, however. We said goodbye to Michelle Chan who had provided efficient administrative support for several years in the BOHS office. That role was taken over by an agency contracted by the publisher, with Emma Steele as main point of contact. Roz Phillips continued to work from the BOHS office as editorial manager. Following a retender exercise during the second half of the year, Oxford University Press (OUP) was successfully reappointed
WHERE WE ARE I am pleased with this last volume, and the work currently under review because I think it shows that the Annals remains in a strong position with a clear mission for the future of occupational hygiene science. I am especially pleased about this, as I have announced that the current volume (64) will be my last as Editor in Chief. Volume 64 will be the eighth volume I have managed in this position, leading the organization through the transition to the new name with the strong support of the editorial board,
EXPOSURE #1 FEBRUARY 2020 - the official magazine of BOHS
BOHS staff and OUP publishing expertise. A search for a new Chief Editor is currently underway by the BOHS (announcement is available at: http://www.bohs.org/aboutus/careers-at-bohs/). So, with this, I thank the BOHS members for the opportunity to serve the organization, and our cause of scientifically-based practices to prevent injury and illness, and promote wellbeing among workers globally.
9
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reasons to attend this unique event 1
Three days of top
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and technical presentations and interactive workshops.
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Over 50 speakers with 19 parallel sessions and workshops.
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IGNITE - an opportunity to presentations, back again as plenary session.
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Five Professional Development Courses.
Free access to the BOHS Mobile App for up to date programme networking.
Aerosol Sampling Methods Update Martin Harper Zefon International DSEAR, ATEX & LEV for Hygienists Adrian Sims Vent-Tech
Four Keynote Lectures from leaders across a broad range of disciplines.
Hygienists Sven Hoffman University of Zurich Risk Assessment for Asbestos and Other Elongate Minerals: Workers, Community, Consumers Andrey Korchevskiy & James Rasmuson C&IH Bruce Case McGill University Andrew Darnton HSE
WARNER LECTURE Simon Weston CBE
Liz Bennet Safety In Design
4
John Cherrie IOM
EXPOSURE #1 FEBRUARY 2020 - the official magazine of BOHS
Victoria Brookbank Minds That Work
The Science and Application of RPE Fit Testing Paul Humphrey 01Dust2Noise Ltd 11
HISTORY OF OCCUPATIONAL HYGIENE PART 8
WHAT COAL TAUGHT US ABOUT DUST MEASUREMENT
SILICA, COAL DUST, AND TB DR. TREVOR OGDEN
it might continue to progress, and lead to disability and death, even if exposure to dust stopped. PMF could occur even if the pneumoconiosis was not very severe, but it became more likely as dust accumulated. Neither simple pneumoconiosis nor PMF were apparently related to the silica in the dust. Coal mined in different parts of the country seemed to carry different degrees of risk of pneumoconiosis, with disease being worst in the anthracite region of South-West Wales. It was known that, as with silicosis, only the fine particles could penetrate to the gas-exchange region of the lung where the damage was done, but the details of cause and effect were unclear.
Fig. 1. Tom Bedford (left) and Cliff Warner, authors of the seminal 1943 report on how coal dust should be measured, and, later, founders of BOHS. The photos are from the time when they were presidents of BOHS, Bedford in 1953 and Warner in 1956.
In Part 7 of this series, we looked at how in the first quarter of the 20th century the Factory Inspectorate applied modern approaches of measurement and control to industries causing silicosis. Better control, and substitution, much reduced this disease in grinding and potteries and elsewhere, but cases still occur today where stone dust is not properly controlled. Continuing risks have been highlighted in the last few years by BOHS in the Breathe Freely construction campaign, and Sharann Johnson wrote in Exposure last year of the epidemic of silicosis in the fitting of engineered stone benchtops in Australia. However, in Britain from the 1930s to the 1980s coal-dust disease attracted much more occupational hygiene effort than silicosis, and as we shall see in this part, that effort fed back in a curious way into standards for silica. We saw in Part 4 how the inhuman working conditions for women and children
12
in mines in the 1830s and 1840s shocked the nation and led slowly to improvements. The effects of dust were less obvious, but about the same time came the first studies of the accumulation of dust in the lungs of coal miners. These, however, remained controversial. Until after World War II, pulmonary tuberculosis (TB) was common in the population, and it was unclear how this infectious disease interacted with the effects of dust, and many experts believed that although silica exposure and TB somehow worked together to increase the risk of dying, coal dust in some way usually reduced the effect of TB.
COAL DUST – WHAT SHOULD WE CONTROL? Apart from the confusion over TB, the effects of coal dust were complicated. It could build up in the lung, and cause simple pneumoconiosis, with little effect on the daily life of the worker. However, coal miners could also develop the much more serious Pulmonary Massive Fibrosis (PMF), and if this was present,
By the 1930s, there were 780,000 people employed in the British coal industry, which was vital for homes and industry. The possibility of a war made conditions for coal-workers politically important. An MRC committee on their lung disease was established, and concluded that there was a form of pneumoconiosis caused by coal dust that was separate and different from silicosis. Their report also included work on the best way to measure dust, by Thomas Bedford and Clifford Warner, who were later to become founders of BOHS. They concluded that only a fraction of a percent of the coal particles which were retained in the depths of the lung were > 5 μm in diameter, and less than 20% were >3 μm, and that the hazardous factor that should be measured for hygiene purposes was the mass concentration in particles below, say 5 μm, “or perhaps the surface area”. At that time the only way of sorting by size was using a microscope. Bedford and Warner favoured collecting the dust with a thermal precipitator (which deposited the particles on a microscope cover slip) and counting particles larger than 1 µm, because this correlated well with the mass concentration of particles < 5 µm. This became the standard method of measuring dust in British coal mines
BOHS.ORG
until 1970; the standards applied were stricter in anthracite collieries and strictest where a tunnel was being driven into stone. In Part 7 we described similar work on silica by the medical inspector of factories EL Middleton in the 1920s. Middleton had concluded that silica particles found in the lung after death were “rarely” greater than 2 μm, and he had designed his measurement method accordingly. The cut-off size for coal will be greater than for quartz, because coal is about half the density (see below), and the
particle shape is different too. Taking these factors into account, Middleton’s 2 μm cut-off for silica will have corresponded roughly to Bedford and Warner’s 5 μm for coal. After World War 2, the British coal industry was nationalized under the National Coal Board, which began a very big study to try to derive safe standards to control pneumoconiosis. This was the Pneumoconiosis Field Research. There were permanent staff based at 25 collieries, measuring the dust exposure of 30,000
Percent of men showing deterioration in 10 years
(a) Using number concrntration
30 25 Scotland
20
North of England Yorks
15
Lancs, N Wales, Mdlds S Walses Anthracite
10
S Wales Steam S Wales Bituminous
5
Kent
0 0
200
400
600
Colliery mean dust concentration in number of 1-5 µm particles per cubic cm
Percent of men showing deterioration in 10 years
(b) Using respirable mass concentration
30 25 Scotland
20
North of England Yorks
15
Lancs, N Wales, Mdlds S Walses Anthracite
10
S Wales Steam S Wales Bituminous
5
Kent
0
0
2
4
6
8
10
Colliery mean dust respirable concentration in mg per cubic m Fig. 2. The relationship of pneumoconiosis progression and dust concentration in a huge study of British coal-miners. When the dust was measured as the number of particles in the fine size range (a), there was no useful relationship, but when the mass concentration in the respirable fraction was measured (b), this was found to be a much more useful measure of risk. Each point is a colliery mean, so it averages a range of conditions. The data used to construct these charts was taken from an IOM paper at the BOHS 1970 symposium, Inhaled Particles III.
EXPOSURE #1 FEBRUARY 2020 - the official magazine of BOHS
men, whose disease was monitored by chest X-rays every 5 years. At first, Bedford and Warner’s method with a thermal precipitator was used, by static sampling of occupational groups, keeping track of the movement of the individual men between occupational groups. An elaborate quality assurance scheme was necessary to ensure agreement between all the people counting the microscope slides. Despite this massive effort, the study produced no useful relationship between dust exposure and pneumoconiosis progression (Fig 2a). The problem can be seen by comparing the South Wales and Scottish mines. As already mentioned, the Welsh mines showed much more disease at the same dust concentration. However, during the study, an instrument became available to measure the respirable fraction gravimetrically, although still as a static instrument. The team measured the number-mass relationship by comparing the two instruments in all the important occupational groups, and converting the ten years of count data to respirable mass concentrations. This much improved the correlation (Fig 2b), and the Scottish and Welsh results, including the single anthracite colliery, looked as if they were part of the same relationship. In 1969, the National Coal Board established a new organization to carry the work of the PFR forward, the Institute of Occupational Medicine in Edinburgh, which in due course became independent and continues to flourish, 50 years later. This outcomes of the PFR led to exposure limits in the coal industry based on respirable mass concentration, but quite apart from that output, the study illustrates the importance of measuring the component of the dust which is actually causing the disease. A hygienist using a thermal precipitator might implement controls at the higher number concentrations, but Fig 2a shows that this would mean that some of the higher-risk environments might be neglected, and instead resources might be used on environments which had a high exposure but low risk. A good correlation between environmental measure and risk (Fig 2b), means that control can be appropriately applied. The Coal Board’s attention to dust control showed in improvement of the disease rates. In 1959,
13
HISTORY OF OCCUPATIONAL HYGIENE PART 8 11.2% of coalminers under 35 in South Wales had pneumoconiosis, but this had reduced to 0.6% by 1975.
MEASURING RESPIRABLE DUST We leapt forward from Bedford and Warner’s statements in 1943 about the size of particles in the lung to their vindication by the National Coal Board research presented in 1970. The work between those dates not only led to the results in Fig 2, but also to modern methods of measuring respirable and inhalable particles used worldwide.
aerodynamic properties – most obviously the rate at which they fall out of the air, but also their inertial behaviour in the bends and divisions of the airways. Both sedimentation and inertia of a particle can be characterized by a quantity called the aerodynamic diameter, which is defined as the diameter of a sphere of density 1 g/cm3 ( 1 kg/dm3) which has the same terminal velocity in air as the particle: a water droplet is such a sphere. This is why silica particles found in the lung are smaller than coal particles – silica has twice the density of
100 Percent of particles in the respirable fraction
90 80 70 60 50 40 30 20 10 0
0
1
2
3
4
5
6
7
8
Particle aerodynamic diameter (µm) Fig. 3. The Johannesburg or MRC definition of respirable dust.
To understand those developments we must go back a bit. It was known that the penetration of particles into the depth of the lung and their deposition there did not depend on the particles’ physical size, but on their
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coal, and a similar small particle will fall twice as fast. Therefore any instrument which selected particles in the same way as the lung airways would not be like a sieve with physical holes, but must select aerodynamically. It also meant that there was no sharp cut-off in the size of particles
which deposited in the lung, but a gradation. The need therefore was for an instrument with a pre-selector which removed the larger particles aerodynamically, like the lung, and which allowed the remaining most hazardous particles to be collected on a filter and weighed, so their concentration could be determined. In 1952 an MRC panel recommended that the selection curve of the preselector should be parabolic in shape, allowing through 50% of particles with an aerodynamic diameter of 5 μm (Fig 3). This roughly matched the size of particles retained in the depths of the lung (the alveoli) which ultimately caused the disease. This definition was adopted by an international conference on pneumoconiosis in Johannesburg in 1959, so it became known as the MRC or Johannesburg curve, and was the standard definition of respirable dust used in Britain until the 1990s. An important practical advantage is that if you pass dusty air through a stack of horizontal plates of the right size, an “elutriator”, so that the heavier particles sediment out, the fraction of each size remaining fits such a curve. Preselectors matching this definition were therefore not difficult to make. When weight-constant filters and small pumps became available, the principles were applied in coal mines by the MRE gravimetric sampler (Fig 4), and it was this which produced the results in Fig 2b. This became the standard respirable dust sampler in British coal mines and for many years the reference sampler in US coal mines as well, because their permitted dust standards were based on the National Coal Board research. By the 1960s, personal sampling was recognized as a better way of measuring exposure, and at the 1965 BOHS Inhaled Particles symposium, two hygienists, Ray Higgins and Peter Dewell, introduced a miniature cyclone preselector which matched the MRC curve. After various manufacturing changes, this remains in use. In the US, personal cyclones were always the sampler of choice for respirable dust, but in surface industry the cyclone and respirable definitions were somewhat different from the British one. However, in British coal mines, the MRE sampler (Fig 4) continued in use as a static sampler. On
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mouth (Fig. 5). The idea started to make its way into standards, but only took off when Vincent and Mark’s IOM sampler for inhalable dust became available in 1986.
HANDLE ELUTRIATOR
NOSE PIECE
FILTER PIPE PUMP
Fig. 4. The MRE gravimetric dust sampler. The dusty air is sucked through a stack of parallel plates (the “elutriator”) designed to select according to the MRC respirable definition (Fig 3). Photograph by courtesy of the University of Toronto Scientific Instruments Collection https://utsic.utoronto.ca/
longwall coalfaces, used in Britain, the air passes along the face, and it was believed that static sampling at the downwind end can satisfactorily characterize conditions on the face.
THE SILICA ANOMALY With the disappearance of deep coal-mining from Britain, silica is the commonest subject of respirable dust measurement. Respirable sampling and gravimetric standards for crystalline silica seem universal, but the reasons are probably practical rather than scientific. The 1959 Johannesburg conference, which adopted the respirable dust definition, recommended measurement of respirable mass concentration for coal, but also recommended “in the case of quartz dust…the surface area of the respirable dust”. An ingenious South African instrument, the DISA, was made which manipulated the diffraction patterns of deposited particles to obtain the surface area concentration, but in the end the ease and familiarity of measuring mass concentration won. However, there has never been a justification for this approach for silica like the one for coal dust illustrated
in Fig 2, and the importance of the surface area of silica is still an occasional subject of research.
THE INHALABLE FRACTION By the early 1970s, measurement of respirable mass was a familiar procedure, but for the hundreds of substances which might occur in the air as particles or droplets, many different samplers were used, and when the ranges of particle size that these collected were investigated, there were found to be big differences which varied with sampler orientation and any outside air movement. Because of this, the measurements in many cases would not have meant much. WH Walton, who 20 years before had been secretary of the MRC panel which defined respirable dust, suggested that a sensible approach was to define “inhalable” dust as what entered the mouth and nose, and to make a sampler which imitated these entry characteristics. In two papers in the mid-1970s, Ogden and Birkett investigated this in calm and moving air, and proposed a specification for the inhalable fraction, based on the directionallyaveraged entry efficiency of the nose and
Fig. 4. The MRE gravimetric dust sampler. The dusty air is sucked through a stack of parallel plates (the “elutriator”) designed to select according to the MRC respirable definition (Fig 3). Photograph by courtesy of the University of Toronto Scientific Instruments Collection https://utsic.utoronto.ca/
EXPOSURE #1 FEBRUARY 2020 - the official magazine of BOHS
There remained the problem of the different European and American respirable dust definitions, but Sidney Soderholm, then at Rochester University, New York, proposed a compromise, and it turned out that that the commonest American and British cyclones could both be used with the compromise by changing the flowrate. This resulted in agreement of the International and European standards ISO 7708: 1995 and EN 481. These incorporated the new respirable convention, specification of the inhalable fraction, and also an extrathoracic fraction for dust depositing in the upper airways. The last four parts of this series have illustrated how increasing understanding and application of principles of occupational hygiene were applied to tackle the major killers of lead poisoning, silica, and coal dust. But this part brings out two other things. Most development work in occupational hygiene was now outside the Factory Inspectorate, and the British workers mentioned in this part were all prominent members of a new organization, which not only brought them together but organized conferences to debate the findings and a journal and proceedings in which many of the key papers were published. The new organization was of course the British Occupational Hygiene Society. How exactly that came about we will see in the next part.
Acknowledgements. The contents of this article have benefitted from the comments of colleagues over many years. Ken Donaldson and Mark Piney in particular helped with this part. A version of this article with references is on-line at https://www. academia.edu/41703111/ Topics_in_the_History_of_ British_Occupational_Hygiene_ Part_8._What_coal_taught_us_ about_dust_measurement
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SOMETHING
SMELLS IN HERE! AN OCCUPATIONAL HYGIENISTâ&#x20AC;&#x2122;S EXPERIENCES OF INVESTIGATING ODOURS IN THE WORKPLACE MICK GRAY, LFOH
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It all started many years ago when I was asked by a client to try and identify the strange odour that appeared occasionally in his office and was upsetting staff. Most odours are volatile organic compounds with some odours from recognised inorganic compounds like the bad egg smell from hydrogen sulfide and the acidic odour of sulfur dioxide. The first thing I realised was that people’s ability to detect an odour was variable with some individuals detecting odours at extremely low levels and others at a level some 100 times more concentrated. Odour thresholds as published are not written in stone and vary greatly from individual to individual. The other anomaly is that an individual’s description of the odour also varies greatly and quite often can be misleading. The second thing I realised was that the concentration of that detectable odour can be less than 1ppb or 1µg/m3. Although we have not got the odour detection limit of a cocker spaniel, we are still very sensitive to odours and therefore ppm levels are no good and unless we can get down to nanogram level on the collection tube we will be wasting our time. So, as a hygienist we are equipped to collect the volatile organic compound on a multibed or Tenax tube using a low flow pump for a 5-10 litre sample. The standard thermal desorption (TD) GC-MS method is the one used for this work. The tube will be desorbed at 2750C and the organic vapours cryofocussed (-300C) before flashvaporisation onto thick film (3μm) capillary GC column (Rtx-5, 30mm, 0.32mm id). The Multibed tube will be spiked with an external standard (o-xylene-d10).
Another use of this technique is what we call the fingerprint analysis. That is, you have an odour penetrating your office/ building possibly from a neighbouring company with a specific odour mixture. One of my first experiences was back in November 2002. I was working with a company who had carried out forensic work on VOC odours and I got to know the chemist Dr Bob Large (sadly no longer with us). Bob had been involved with the Soham Murders case in trying to identify the source of the petrol used to burn the bodies in the ditch. This was identified as coming from the local garage. Bob, in the meantime, had picked another murder case, and had asked me to go out sampling with the Essex police at various locations around the areas. The case was a murder investigation, Ian Jarvis had strangled his brother’s girlfriend, Marie Couldridge, and set fire to her and her flat to hide the evidence. When Jarvis was arrested the police noticed his clothes smelt of smoke. He had gone back to the flat to make sure the flat was burning and add more accelerant. When he entered the building her body was smouldering, Jarvis’s clothes picked up the odour of the burning
fatty tissue along with all the other VOCs. Following Jarvis’s arrest next morning his clothes were collected and sealed in a nylon bag. TD GC-MS was able to identify the smoke odour on Jarvis’s clothes contained the unique odour of burning fatty tissue from a human body.
I can see you asking what was my role in all of this. Because Jarvis had said that he had made a bonfire in a field, he had also been to a greasy café and had a bacon sandwich and to a smoky pub for a drink, we had to go to all these places and sample the indoor air to identify the different odours detected and eliminate them from the analysis.
This will not give us absolute concentration values but good guidelines and a good library fit for the number and nature of the compounds detected. Once we have the analysis report the real research begins. We have to detect which compound or group of compounds are unusual in this indoor environment and are causing the odours. We are looking for chloro, fluoro, sulfur, aldehyde and amine compounds and possibly high boiling alcohols. Once we have identified a possible suspect, we than must try and identify where it comes from or how it might be produced accidently. Although the client needs you to identify the odour, what he really wants is to get rid of it and Identify the cause to prevent it happening again.
EXPOSURE #1 FEBRUARY 2020 - the official magazine of BOHS
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I actually went to court in Chelmsford as a witness of fact and saw Jarvis in the stand. Incidentally Jarvis was convicted and got life.
SOME ODOUR DETECTION SURVEYS I was once asked to go to a bank due to an odour problem which was re-occurring every 2-3 months causing the staff to have watering stinging eyes that lasted for 10-15 minutes. One of my main problems is being there when the odour is present, so in this case I left a couple of pumps and tubes and showed the maintenance staff how to take the samples. About a month later I got a call to pick up the samples and have them analysed. The GC-MS scan showed over 90 VOCs on the scan which is common for an indoor air environment. One compound stood out from the usual VOCs. This compound was Methyl Sulfonyl Chloride present at less than 1ppb. This compound is a lachrymator and is possibly the cause of stinging eyes. This is an unusual compound to find within the indoor environment, so where did it come from? Research showed that the most likely
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cause was a reaction with organic matter and sulfur, chlorine products. During the survey I had looked around the building and saw that the air handling system air intake was at low level. I questioned the maintenance staff with regard to any activity involving chemicals, drain cleaners etc. To my surprise they admitted that they had used sulfuric acid drain cleaner and as they always do pour a quantity of bleach down the drain as a final clean and disinfectant. Hey presto we have the answer. The maintenance staff stopped doing the clean in this way and the problem never returned.
FINGERPRINT ANALYSIS FOR KITCHEN ODOURS From report: A Volatile Organic Compound odour scan to nanogram level was carried out in the kitchen and the nearby office area of the bank. The samples were collected to try and establish the source of cooking odours in the office area adjacent to the kitchen. The scan carried out identified 45 compounds in the kitchen and 36 in the office area, of which 25 were identical to the compounds found in the kitchen.
As the kitchen is adjacent to the office wall there is the possibility that there may be some ingress of odours above the ceiling in the void to the office area. This needs a thorough investigation. Consideration should also be given to checking the integrity of the extract duct on the positive side of the fan as any leaks in the duct will add odours to the void. Further investigation found out that the ceiling voids between the buildings were not isolated as they thought.
IDENTIFICATION OF ODOURS IN VEHICLE: At the request of a client a Top Ten Volatile Organic Compound scan to nanogram levels was carried out within his brand-new vehicle. During a recall of this new car by a major car manufacturer, an engineer spilled diesel fuel all over the leather seats and in the back well of the car. The seats were renewed and several clean ups were carried out by the manufacturer. After many returns of the car where the client complained of diesel fumes giving him headaches, the manufacturer said, â&#x20AC;&#x153;that
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there was nothing else they could do and that no one in their sales team could detect any diesel fumes”. The client was not happy with their response and wanted to confirm that the there was no trace of diesel fumes within the car.
m3. The static result in the car was virtually three times the BREEAM standard. This level of total VOCs in an office environment would be unacceptable and cause many complaints form staff. High background levels of VOCs tend to cause eye, nose and
throat irritation and headaches. The only VOC detected which is not part of the diesel fuel fraction was Propan-2-ol or Isopropanol which was used in the clean-up.
The sample was collected in back seat well on a Tenax tube using a low flow pump to collect an 8.35 litre sample. The vehicle was sampled on a Saturday morning after being stationary overnight. The combination of compounds detected confirm that there are diesel fumes present within the car with the amount of Ethyl Benzene present at over 5 times the published odour threshold value. Although the concentration of the individual Volatile Organic Compounds (VOCs) were less than any workplace exposure limit for any compounds, the overall concentration of the total VOCs was 922µg/m3 and that’s not including the other 54 additional compounds detected on the tube. The standards for total VOCs in the indoor environment for good air quality are <300µg/m3 (BREEAM) with some standards at levels <500µg/
As result of the report the client got a brand-new car and an apology.
EXPOSURE #1 FEBRUARY 2020 - the official magazine of BOHS
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Abstracts & Bookings Open Abstract Deadline 6 March 2020 This symposium is the leading international forum at which recent progress in workplace, residential and environmental exposure assessment strategies and associated analytical air sampling and biomonitoring methodologies can be discussed. The symposium is supported by a consortium of European and International Institutes of Occupational and Environmental Health and Safety, from whom, members of the scientific committees are drawn. An exciting programme is planned which combines thought-provoking keynote presentations with accompanying oral presentation sessions. Practical workshops and presentations for hygienists will be included.
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GRATICULES AND CHOCOLATE: STEPHEN BECKETT’S LEGACY DR. TREVOR OGDEN
Only a handful of members will remember Steve Beckett from his days in BOHS, but hundreds will have benefitted from the microscope eyepiece graticule he co-designed when he was a member, which made airborne asbestos measurement easier and more accurate. Sad to say, Steve died on 9th January. Steve arrived at the Institute of Occupational Medicine in Edinburgh in late 1971, after a physics degree at Durham, and a doctorate at York which involved maintenance and manipulation of high vacuums. His main job at the IOM was to generate steady clouds of asbestos at various concentrations in rat inhalation experiments, which was good exercise for his experimental skills, but over the next few years he also published 11 papers in the Annals of Occupational Hygiene and 8 elsewhere, which had a permanent effect on the way asbestos is measured worldwide. Steve collaborated with the laboratories of the three major British asbestos manufacturers and the Factory Inspectorate, who were all using the membrane filter method for measuring airborne asbestos concentrations. They all believed that they used the standard method, but Steve conducted slide exchanges, which showed that the mean results that the laboratories obtained on the same samples differed by a factor of three, with larger differences on individual samples. Henry Walton, Steve’s boss, knew well the errors in microscope counting of coal dust particles collected with thermal precipitators, and the acknowledgements to the Beckett and Attfield paper say that he suggested the trial of asbestos counting. Similar big differences were found in later exchanges between major laboratories in
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nine countries, and later still huge differences between laboratories in this country. It was clear that the intense public debates about what a safe standard for asbestos might be were of no point if the concentration depended so much on who measured it. Different laboratories were found to be using small variations of the standard method, but a large part of the differences in results were due to unexplained differences in counter perception and behaviour. In 1978 the Government’s Advisory Committee on Asbestos strongly recommended interlaboratory quality control checks, and this led in 1982 to the RICE scheme, which became available to all laboratories in 1984. Participation in RICE remains virtually compulsory for British laboratories using the membrane filter method in the workplace. Asbestos fibres are only counted if they are longer than 5μm, with diameter < 3μm, and length:diameter ratio >3:1, so it is necessary to use an eyepiece graticule, which superimposes a scale on the field of view. The graticule often incorporates a square or circle, and this can be used to define a countable area. Steve’s results showed, to everyone’s further surprise, that laboratories which just counted the fibres within the graticule area found almost three times as many fibres/mm2 (for chrysotile) as laboratories which tried to count fibres in the whole field of view. This was true for graticule areas smaller than about 100 μm in diameter, and the smaller the area, the
greater the effect. It demonstrated again the big differences produced by subtle psychological effects of perceiving and counting fibres. Laboratories were using graticules of various designs, but all intended for compact particles. The linear scales on these had to be used to measure the length and diameter of curly and intersecting fibres, to see whether they fitted the definition. Surely only a perfectionist with a very patient employer would go to this trouble of measuring 100 fibres per sample – there would be a lot of estimate of dimensions by eye. Steve and Henry Walton got together and designed a more suitable graticule, with one scale with 5μm divisions and a perpendicular one with 3μm divisions. Round the perimeter were examples of rectangular shapes of various sizes with 3:1 aspect ratios. To get these sizes right, each graticule had to be individually made for the microscope for which it was intended. This design rapidly found favour, and today is recommended or required all over the world. (Later, John Cherrie investigated the graticule area effect, and showed that it was not significant if the number of fibre ends in the graticule area was counted and halved, as in the modern method in HSE’s “Asbestos: The Analyst’s Guide…”) Gradually the asbestos-measuring world woke up to its deep problems. From 1977 I was responsible for these measurements in HSE, and attended a meeting with
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Steve in Washington DC, organised by the international asbestos industry. It was a pleasure in the discussions to hear people argue over the problems, and from time to time suggest an experiment that should be done, and then to hear Steve, in his clear but modest manner, explain that he had already done it, this was how, and these were the results and conclusions. And then, at a time when the world was beating a path to his door, Steve changed career. He had different priorities, and he wanted to move back to York, where he had been brought up, and where he had met Dorothy. In 1979 he got a job in production research with Rowntree’s chocolates, and Steve and Dorothy settled in York and at Haxby & Wiggington Methodist Church. The bee-hives that Steve had introduced
to the garden of Bush House, where he had his experiments, went with them. The recruitment interviewers at Rowntree asked him if he would mind if he didn’t publish as many papers. Maybe his publishing pattern did change, but he now established an international reputation in his new field, and travelled to Rowntree’s (and, after the takeover, Nestlé’s) factories in different parts of the world. In 1988 he edited a multi-author work, “Industrial Chocolate Manufacture and Use”. The 5th edition, now with two co-editors, appeared in 2017 as “Beckett’s Industrial Chocolate Manufacture and Use”. It is rare for a book to become so wellknown that the original author’s name is incorporated into the title, and very rare for this to happen while the author is still alive.
EXPOSURE #1 FEBRUARY 2020 - the official magazine of BOHS
Sadly, if there are future editions, they will be without Steve’s input. He developed diseases which left him progressively incapacitated, and died of pneumonia at the age of 73. My wife and I visited him and Dorothy several times, and he remained the cheerful and self-effacing Steve that we had always known, and a pleasure to visit. His memorial service in Haxby was attended by about 200 friends and colleagues. His family, his graticule, and his book, will remain as his legacy.
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Occupational Hygiene 2020 (OH2020) is the worker health protection in the UK, focusing on occupational hygiene and the prevention of occupational ill-health and disease. This year the location is the city of Bristol, straddling the River Avon in the southwest of England with a prosperous maritime history.
For the full conference See the programme rates andfull programme and book your place please see inside
Bristol The Premier Conference for Occupational Hygiene in the UK
Bristol Marriott City Centre Hotel April 20-23 2020
