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J Occup HealthJ Occup HealthJournal of Occupational Health1341-91451348-9585Japan Society for Occupational Health 298991982018-0121-RA10.1539/joh.2018-0121-RASpecial ArticleGuidelines for personal exposure monitoring of chemicals: Part VI Expert Division of Occupational Hygiene & Ergonomics, the Japan Society for Occupational Health, "The Committee for Personal Exposure Monitoring"  0000-0003-2406-6584Hashimoto Haruo 1Yamada Kenichi 2Hori Hajime 3Kumagai Shinji 30000-0003-4766-9281Murata Masaru 4Nagoya Toshio 5Nakahara Hirohiko 6Mochida Nobuyuki 71 
University Management Center, Tokyo Institute of Technology
2 
Occupational Health Research and Development Center, Japan Industrial Safety and Health Association
3 
Department of Environmental Management, School of Health Sciences, University of Occupational and Environmental Health
4 
Faculty of Science and Engineering, Waseda University
5 
Professor Emeritus, Waseda University
6 
Safety Health and Environment Department, JXTG Nippon Oil & Energy Corporation
7 
Environment and Safety Group, Kawasaki Refinery, JXTG Nippon Oil & Energy Corporation
Correspondence to: H. Hashimoto, University Management Center, Tokyo Institute of Technology, NE-31, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan (e-mail: hashimoto.h.ah@m.titech.ac.jp)This article is the last part of a six-article series on the guidelines for personal exposure monitoring of chemicals continued from the last number: Vol. 60 (2018) No. 3 p. 203-207. doi: 10.1539/joh.2018-0060-RA Supplementary materials (Appendices) are available in the online version of this article.

14 6 2018 20 7 2018 60 4 275 280 16 5 2017 6 7 2017 Journal of Occupational Health is an Open Access article distributed under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. To view the details of this license, please visit (https://creativecommons.org/licenses/by-nc-sa/4.0/).This Document, "Guidelines for personal exposure monitoring of chemicals" ("this Guideline"), has been prepared by "The Committee for Personal Exposure Monitoring" ("the Committee") of the Expert Division of Occupational Hygiene & Ergonomics, Japan Society for Occupational Health. Considering the background of the growing importance of personal exposure monitoring in risk assessment and the need to prepare for the introduction of monitoring using personal samplers from an administrative perspective in recent years, the Committee was organized in November 2012. The Committee has prepared this Guideline as a "practical guideline" for personal exposure monitoring, so as to offer proposals and recommendations to the members of the Japan Society for Occupational Health and to society in general. The scope of this Guideline covers all chemical substances and all related workplaces regarded as targets for general assessment and the management of risk. It thus is not to be considered to comment on legal regulations and methodology. The main text provides the basic methods and concepts of personal exposure monitoring, while 31 "Appendices" are provided in this Guideline throughout the series; technical descriptions, statistical bases, and actual workplace examples are provided in these appendices, to assist better understanding. The personal exposure monitoring described as per this Guideline is equivalent to an "expert-centered basic method to reasonably proceed with the assessment and management of risk at workplaces." It is considered that practicing and expanding on this method will significantly contribute in reforming the overall framework of occupational hygiene management in Japan.

ChemicalsControlExposure monitoringOccupational hygieneRisk assessmentWorkplace
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Chapter 3: Characteristics and Utilization of Personal Exposure Monitoring-Conclusion
1. Role and responsibility of expert
1-1 Risk assessment supervisor and monitoring staff
A risk assessment supervisor is a facilitator who comprehensively supervises the entire process of personal exposure monitoring (steps 1 to 9 in Fig. 2.1). They are thus required to exhibit appropriate flexible determination in the various stages. The supervisor is also in the position of advising appropriate risk reduction measures to the manager and, from an expert point of view, to actively support the manager in terms of the risk reduction measures advised. In other words, a risk assessment supervisor is a professional who supervises the assessment and management of risk, a professional whose task is similar to that of experts in the field of industrial hygiene and ergonomics in Europe and the USA, known as occupational hygienists. Descriptions of occupational hygienists are provided in the appendix (please refer to Appendix 29).

A risk assessment supervisor is therefore required to possess the relevant expertise and judgment to fulfill his/her duty, a role that also requires adequate education. The first requirement needed is education in the methodologies of the personal exposure monitoring, which is described in this Guideline. Required education also includes knowledge of toxicity and toxicology of chemical substances, actual measuring methods, instantaneous measurement and real-time monitoring, engineering improvement measures and personal protective equipment. Furthermore, risk assessment supervisors require an attitude toward occupational hygiene with which they seek not to discover problems but rather to "solve problems".

A "monitoring staff" member who performs actual monitoring work under the supervision of a risk assessment supervisor (steps 3 to 6 in Fig. 2.1) is also required to receive education according to his/her role. Since Working Environment Measurement experts have already attained to a certain level of knowledge, it is considered appropriate that they would be involved in the monitoring of chemicals according to the category of their qualification after receiving specific education on personal exposure monitoring.

To promote future personal exposure monitoring in Japan, it is necessary to develop the curricula, methodology and operational organizations required for the above expert education.

It is also necessary for both risk assessment supervisors and monitoring staff to receive continuous education even after the completion of their training. Because the scope of the necessary education is broad, and because toxicological information and monitoring techniques concerning chemicals are evolving fast, the initial education alone is not necessarily sufficient. It is thus strongly recommended that they actively disseminate their experience and knowledge through academic conferences and research presentation meetings, and also by sharing them with others to enhance friendly competition. Personal exposure monitoring in Japan has not been widespread; hence, accumulation of experience at a wide variety of workplaces will come to constitute a universal property of domestic industrial hygiene and thus will contribute to the fostering of the risk assessment supervisors and monitoring staff.

1-2 Ethics and responsibility of experts on personal exposure monitoring
Personal exposure monitoring involves a variety of freedom for the expert's flexible determination. This entails a heavy responsibility. For this reason, adequate understanding of, and compliance with, established professional ethics are required. Table 3.1 summarizes the primary code of ethics required for performing duties.

Table 1. Major ethical considerations in the course of performing duties by experts involved in personal exposure monitoring

Reference: ABIH Code of Ethics. Code of Ethics for Occupational Hygienists by the Japan Association for Working Environment Measurement (see References 1), 2) in Chapter 3 for quotation).	
1.	Recognize the first mission to protect workers' health and welfare.	
2.	Comply with laws, regulations, policies, social, and ethical standards.	
3.	Avoid a conflict of interest with employers, customers, workers or the public.	
4.	Assure that a conflict of interest does not compromise the essential purpose of employers, customers, workers or the public (attainment of health and welfare) and does not influence professional decisions.	
5.	Deliver good quality services based on the best efforts in accordance with professional and objective decisions.	
6.	Recognize the limitations of one's professional abilities based on his/her knowledge, skills, experience, and other relevant considerations, and provide services within such scope.	
7.	Follow appropriate health and safety procedures in the course of performing duties.	
8.	Maintain and respect the confidentiality obtained in the course of professional activities, unless the information implies anti-social contents or failure to disclose the said information would likely harm the health and welfare of workers or the public.	
These ethics are almost the same as those necessary for occupational hygienists. For instance, the Japan Association for Working Environment Measurement1), the American Board of Industrial Hygiene (ABIH)2), and the International Occupational Hygiene Association (IOHA)3) have strictly stipulated the professional ethics required for occupational hygienists.

A risk assessment supervisor and a monitoring staff member are, to the best of their abilities, responsible for the performance and recording of the assessment as well as the accurate, conscientious and ethical monitoring of personal exposure, with the precise reporting to the employer. When they are required to engage in flexible determination, what the decisions are based on shall be clarified and recorded. On the other hand, it is the employer's responsibility to accept and understand the report, and also for the implementation of appropriate control measures to protect the workers from exposure. Therefore, should an issue of any adverse health effects on workers arise, it is generally believed that the principal responsibility lies on the employer, as long as a risk assessment supervisor and a monitoring staff member have adequately fulfilled their duties.

Typically, potential problems with ethics concerning personal exposure monitoring include issues regarding the interval for reassessment and monitoring. In this Guideline, it is considered that the flexibility in setting the interval allows more efficient risk management and would result in motivating employers to enhance the control level. However, at the same time, there is a room for ethical concerns to arise. As is often the case when performing current Working Environment Measurement, it is sometimes that case that when monitoring, an employer or the manager provides instructions to workers to reduce the airborne concentration further than usual by reducing the amount of chemical substances, or by opening the windows. If the control class is good and if the system allows the extension of assessment and monitoring intervals, such a fraudulent motivation may occur (for instance, the control class 1A allows reassessment to be conducted after 3 years (basically), thus considerably reducing the monitoring costs). Therefore, a risk assessment supervisor must consider such situations, in which compliance with ethics for the performance of duties would be essential. Similarly, prevention of fraud and compliance with managerial ethics are vital for employers as well. It is thus necessary to conduct measures, dissemination, and enlightenment for the employers.

2. Features of personal exposure monitoring and its significance in occupational hygiene
2-1 Features of personal exposure monitoring
Features of personal exposure monitoring include technical features as a monitoring method and system or operational features.

Table 3.2 shows features of monitoring techniques, including features of area monitoring as a reference. Since personal exposure monitoring compares the measurement results of workers' breathing zone with the occupational exposure limit, the greatest strength is its capacity to directly assess the health risk, which constitutes the core method for health risk assessment. Other advantages of personal exposure monitoring include assessment covering work hours and adaptability to the diversity of work (proximity, intermittent, complex, etc). Thus it is often pointed out that when there is a high concentration of hazardous substances in the work environment, the resultant area monitoring can lead to an overestimation compared to personal exposure monitoring. This is because workers stay in the workplace for a very short time. By contrast, when there is a low concentration of hazardous substances in the work environment, the resultant area monitoring can lead to an underestimation due to the fact that workers are subjected to high exposure in other workplaces. In personal exposure monitoring, the contaminant generation sources can be often identified through workplace observations. This is described separately (Appendix 20).

Table 2. Features of personal exposure monitoring–“Monitoring techniques” (including features of area monitoring for reference)

Item	Personal exposure monitoring (monitoring in breathing zone)	Area monitoring	
Note: The above is based on the assumption of eight-hour/short-term monitoring, and A-measurement/B-measurement.
*1: Possible by comparing the results of measurements with the occupational exposure limit.
*2: Generally identified with the observation results of workplaces (please refer to Appendix 20).	
Direct assessment of “health risk”	Possible (*1)	Impossible	
Contribution of work hours	Yes	None	
Response to movement of workers and diversity of work (proximity, intermittent, complex, etc.)	Possible	Difficult	
Cases where monitoring is difficult (narrowness, danger, etc.)	Almost none	Sometimes yes	
Burden on workers (weight of samplers etc.)	Sometimes yes	None	
Identification of source of generation	Generally possible (*2)	Generally possible	
Table 3.3 shows system or operational features, including features of area monitoring as a reference. Personal exposure monitoring involves a large number of substances (there are around 1,000 kinds of substances with occupational exposure limits) and can be used widely in any target workplaces. Workers are grouped into similar exposure groups (SEGs) for each substance.

Table 3. Features of personal exposure monitoring-"System and operation" (including features of area monitoring for reference)

Item	Personal exposure monitoring (this Guide)	Working Environment Measurement (statutory)	
*1: In principle, substances having occupational exposure limit, about 1,000 kinds.
*2: Outdoor workplaces are subject to the guideline on the workplace environment (LSB Notification No.0331017).	
Purpose	Risk assessment	Management of workplace environment	
Substances to be monitored	Many (*1)	Specified substances (90 kinds or a bit more)	
Target workplace	All	Indoor only (*2)	
Categorization of objects to be moniored	Similar exposure group (SEG)	Unit work area	
Instantaneous measurement	Widely available	Detector tube partly usable	
Method of monitoring	Eight-hour monitoring, short-term monitoring	A-measurement, B-measurement	
Monitoring duration (eight hours or A-measurement)	Eight hours (basically), but may be shortened to two hours	10 minutes or more for one point, one hour or more in total	
Number of samples (ditto)	Five (basically), but one to four also allowed	Five or more	
Statistical assessment value	Arithmetic mean, 95 percentile	Estimated value of arithmetic mean, 95 percentile	
Control class	Six classes	Three classes	
Involvement of monitoring staff in the formulation of control measures	Strongly recommended	Not required	
Format of report	Not defined specifically	Model format	
Management of change in workplace	To be performed	Not performed due to no such concept	
Reassessment and re-monitoring	Reassessment and re-monitoring	Periodic measurement	
	Frequency reduced for better control	(Partial mitigation system)	
Monitoring practitioner	Risk assessment supervisor, monitoring staff	Working Environment Measurement expert	
Procedure for monitoring	Much room for flexible determination	As per the stipulated procedure	
Easiness of monitoring	Requiring knowledge, experience, and skill	Relatively easy	
Burden on employer	Lowers as time passes	Nearly constant	
Reasonable management according to risk	Possible	Difficult	
Motivation to employer	Large	Very small	
Personal exposure monitoring allows instantaneous measurement (using detector tubes or real-time monitors) as a mean for basic characterization of workplaces. This is considered a significant benefit due to the fact that instantaneous measurement can be recognized as a screening assessment of exposure, allowing flexible utilization to contribute to efficient exposure monitoring, responding to irregular and intermittent work in the research laboratories, as well as improving monitoring practices in small and medium-sized workplaces.

The basic assessment method of measurement results consists of using the arithmetic mean and the 95 percentile, which is similar to the case of Working Environment Measurement. However, personal exposure monitoring is characterized by the fact that the control class is divided into six classes. In these six classes, the control class 2B (about 10 to 40% of the workers potentially exceeding the occupational exposure limit) requires control measures, while control measures are not necessarily required in the Working Environment Measurement. This is the unique feature of this guideline.

With respect to reassessment and monitoring, significant features can be seen. One of these is that reassessment and re-monitoring are separated, each having its own basic frequency and modifiable range. Since the better the control class, the lower the frequency becomes, it is considered to be a big motivation for employers to implement exposure reduction measures. Even for the same control class, there is a room for mitigation of the frequency, depending on the risk assessment supervisor's decisions based on the stability over time, etc. Moreover, the management of change is required prior to the reassessment and monitoring, and it guarantees the restriction of risk associated with changes in the equipment and contents of work.

In terms of the overall procedure of monitoring, personal exposure monitoring offers flexibility, such as execution or non-execution of monitoring, sampling method (number of samples, monitoring duration, etc.), and frequency of re-monitoring depending on the risks of SEGs estimated in the basic characterization or reassessment, thus allowing reasonable progress of risk assessment and management.

Concerning ease of monitoring, a risk assessment supervisor requires a certain level of knowledge, experience, and skills for personal exposure monitoring because there is a room for flexible determination and because the supervisor shall be proactively involved in the design of control measures.

The burden on employers (in terms of labor costs and other expenses) may be relatively heavy at the introduction of personal exposure monitoring method. This is due to the fact that the increase in the number of samples and longer duration, and also because of the lack of experience of a risk assessment supervisor and the lack of past measurement results. However, for instance, within a short term of 1 to 3 years, a sharp reduction in this burden may be anticipated because the frequency of reassessment and monitoring would be reduced with improved control class and because the supervisors' efficient decision-making would be expected based on the experience and the accumulated past data.

Detailed considerations in this regard are provided in the appendix (please refer to Appendix 30).

Summarizing all of the above, personal exposure monitoring has definite beneficial features from the viewpoint of the reasonable risk-based control. For employers, personal exposure monitoring as a mean of risk assessment and risk management shall be a big motivation.

2-2 Social effects and future prospects of personal exposure monitoring
In the case of personal exposure monitoring, a risk assessment supervisor can reasonably proceed with risk assessment and risk management by exercising his/her flexible determination as well as their originality and ingenuity. Thus the supervisor has a motivation to improve his/her own skills and to enhance their judgment. However, when there is no room for originality and ingenuity, and the supervisor shall follow the existing protocols, such motivation may not arise. From the point of view of employers, improvement in the control situation of workplaces would reduce the load of assessment and monitoring. Securing of a risk assessment supervisor of good quality and the utilization in full of his/her judgment would ensure such improvement. Consequently, it will come to be a motivation for employers to foster risk assessment supervisors and to control the risk of workplaces voluntarily and proactively through continued employment of a risk assessment supervisor.

Based on the above two benefits, various social developments can be expected. Firstly, a mechanism for educating risk assessment supervisors and monitoring staff is required. For the foreseeable future, lecture classes are conceivable. The need for professional education courses at a university or postgraduate level may also increase. At the same time, a qualification system (e.g., certification) of such engineers may become necessary. In order to proceed with control of workplaces through originality and ingenuity, the importance of mutually reporting and sharing knowledge among other workplaces (such as good practices around assessment and management, or high-risk work) would arise. This would lead to more active academic social activities. Through such activities, the overall level of industrial hygiene in Japan will improve, and the accumulated industrial hygiene knowledge will then be disseminated to related engineers through various media. Moreover, local academic societies of industrial hygiene could deliver key information, such as emerging risks and case reports, and enlighten the administration and employers. Within business establishments, on the other hand, as a risk assessment supervisor proactively controls the workplaces, their responsibility and influence will become stronger. Then, it is expected that, even without legal regulations, risk reduction measures against problems will be implemented under the leadership of risk assessment supervisors. For employers, after the continuous course of such proactive control practices, a voluntary attitude "to take voluntary measures against high risk" will develop within them, replacing the current passive attitude of "performing only the legal requirements." 

As mentioned in the previous section, personal exposure monitoring has technical and system/operational features. In order to ensure the motivations and social propagation effects based on personal exposure monitoring, it is necessary to make use of the latter, system/operational features, where risk assessment supervisors perform with flexible determination. As a management technique, this corresponds to the methodology, in which the goal is set, and the process toward the goal is left entirely up to a practitioner (this is referred to as 'management with performance standards'). If, by contrast, all implementation details are defined (this is referred to as "management with specification standards"), a practitioner will simply follow the rote procedures. In this case, neither motivations nor the afore-mentioned beneficial social effects can be expected. And therefore, in order to make a real use of the advantages of personal exposure monitoring in the field of occupational health, it is necessary to fully harness not only the monitoring techniques but also the system/operational features. (However, although flexibility in the system and operation is desirable, it may be intentionally misapplied (please refer to Section 1-2 in Chapter 3). Employers and risk assessment supervisors, therefore, should keep this in mind and prevent it).

In the legal systems concerning exposure control in the USA, European countries, Australia as well as in other countries, this performance standards concept has already been incorporated, under which personal exposure monitoring with professional flexible determination has become widely adopted. As a result, during the last 40 years or so, professional engineers' groups called occupational hygienists or industrial hygienists have grown to a great extent. This has enhanced the level of nationwide occupational hygiene and has become an important social function. This is an example of the successful social propagation effect where the personal exposure monitoring has been adopted. Details on this are provided in the appendix (please refer to Appendix 31).

Thus, it is expected that an appropriate application of personal exposure monitoring would enhance the level of nationwide control of chemical substances. This can have a propagation effect over controlling all hazardous factors, including not only chemical substances but also physical, biological, and human engineering aspects. Since many physical factors (noise, radiation, etc.) have their own exposure reference values, the method of personal exposure monitoring may be applicable as a fundamental concept. Although such a method is not directly applicable to the other hazardous factors, the personal exposure monitoring presented in this Guideline shall be a "basic method used by the experts for the reasonable risk assessment and risk management," and this concept itself may be applicable. In other words, promotion of the personal exposure monitoring presented in this Guideline would eventually bring the enhancement of the entire occupational hygiene control in Japan.

As mentioned above, the personal exposure monitoring (the entire process presented in this Guideline) is not just a monitoring technique. It may be regarded as a "problem-solving method" with a potential to build the subject of occupational hygiene nationwide, leading to a "paradigm shift (i.e., a complete change in the framework of thinking) " of occupational hygiene.

3. Conclusion
As repeatedly described in this Guideline, personal exposure monitoring is the most basic and accepted method, toward the risk assessment and management of chemical substances. In Japan, the implementation of personal exposure monitoring has been very much limited. It must be better highlighted for the proper implementation and further adoption in the future.

In this Guideline, personal exposure monitoring is not regarded as a mere measurement in the narrow sense of the word. It is to be recognized comprehensively as a process of the risk assessment and risk management. And on that basis, the procedure and judgment criteria for each factor are shown as a guideline. Moreover, a responsible professional is assigned as a risk assessment supervisor, and the freedom of his/her flexible determination is adequately secured to promote the precision and simplicity depending on the risk. Promulgation of personal exposure monitoring such a procedure would lead to not only the effective control of each workplace but also to overall improvement, on a nationwide level, of occupational hygiene.

It is conceivable that personal exposure monitoring will be officially incorporated into the legal system in future. It would be our great pleasure if, in the process of system design in the administrative organizations, the contents of this Guideline, the reasonable procedures with respect to expert flexible determination, were used as references.

At the present moment, this Guideline has been summarized and published only once. But this "first edition" will be subjected to future revisions as needed. Japan does not have adequate accumulation of insights into personal exposure monitoring. It is expected that this Guideline shall be developed into a more complete form based on the actual outcomes and experience. In this sense, the offering of valuable opinions, particularly those based on experience, will be highly appreciated.

Those involved in national occupational hygiene are kindly requested to thoroughly understand the contents of this "GUIDELINES FOR PERSONAL EXPOSURE MONITORING (Expert Division of Occupational Hygiene & Ergonomics) " as a base for the procedure for personal exposure monitoring and to positively make the best use of it. We hope that personal exposure monitoring will become widely propagated and utilized in Japan.



Conflicts of interest: None declared

Supplementary material: This article contains supplementary material (Apendix), which is available in the online version (doi: 10.1539/joh.2018-0121-RA).

Supplementary Material
APPENDIX Click here for additional data file.
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