Exposure assessment is the process of estimating or measuring the magnitude, frequency and duration of exposure to an agent, along with the number and characteristics of the population exposed”. (US EPA) Results of exposure assessment help industrial hygienists understand exposure level of workers and design the required control measures to protect workers. Also, it could be used for exposure-response in epidemiologic study. Exposure assessment involves industrial hygiene sampling and analysis and estimating true level of occupational exposure.
2. Uncertainty and variability in exposure assessment
Uncertainty in occupational exposure assessment cause imprecise estimation of true exposure. Two 2 major sources of uncertainty are: natural variability and the lack of knowledge or fundamental ignorance. (Bullock and Ignacio, 2006; Keil et al, 2009; US EPA, 2008)
2.1 Natural variability or Type I uncertainty plays a big role in occupational exposure assessment since it causes heterogeneity and large variability as well as lognormal distribution and autocorrelation in occupational exposure data. Natural variability cannot be eliminated but can be characterized, quantified and minimized by proper industrial hygiene sampling strategies and statistical methods. Examples of natural variability in occupational exposure assessment are: variability between workers such as breathing rate or height of workers; variability between work days or working shift such as cycle of production, rate of production; variability of work environment such as air movement, ventilation rates, chemicals emission rate, difference of temperature; and variation in time. (Bullock and Ignacio, 2006; Keil et al, 2009; US EPA2008)
2.2 The lack of knowledge or Type II uncertainty results from limitation of knowledge in occupational exposure assessment. Example of this type of uncertainty are limitation in industrial hygiene monitoring instrument or the limited availability of actual exposure level of workers population or limitation in method of analysis. (Bullock and Ignacio, 2006; Keil et al, 2009; US EPA2008)
Among studies of variability in occupational exposure assessment, several studies have investigated effect of variation in time in occupational exposure estimation. Results from those studies confirmed that variation in time causes concentration variation and leads to less precise estimation of exposure. Moreover, increasing of sampling time or number of samples will decrease GSD, thus increases precision. (Buringh and Lanting, 1991; Lee et al, 2004; Lee et al, 2008; Louma and Batterman, 2000; Spear et al, 1986; Woskie et al, 1994)
3. Lognormal distribution
The two common exposure distributions in occupational exposure are normal and lognormal distribution. Occupational exposure data have long been described as log-normally distributed. (Bullock and Ignacio, 2006; Esmen and Hammad, 1977) There are several causes that lead occupational exposure data to the lognormal distributions:
Throughout the risk assessment process, ideas for action were identified and documented. The documentation of these ideas led to the development of potential action item worksheets which were then selected, prioritized, and refined. Detailed risk assessment information for each hazard is included and located through this document.
DeArmond, Stephen J., M.D., Ph.D., Safar, Jiri, M.D., Groth, Darlene, A.B., Prusiner, Stanley B., M.D. “Prions” Office of Health and Safety. 28 July 2006 < www.cdc.gov/od/ohs/biosfty/bmbl4/bmbl4s7d.htm>.
An extensive part of WEACT’s mission is to “promote actions that people can take in their own homes as well as addressing the larger policy issues of where industry is located and its effects on the health of neighborhood residents” (Carlson & Stroebel). In order to take these actions and help guarantee that policy makers were listening, the creation of the risk maps were vital. The risk map was able to present areas where “young people experienced foul odors, irritated throats, watery eyes, shortness of breath, and other self reported symptoms” (Corburn 55). The mission of this street science project was to safeguard the community’s health concerns, in addition to allowing further action to be implemented. However, the risk maps were not the only way that WEACT sought to address these
Work practice controls: controls reduce the likelihood of exposure by modifying procedures and reducing the risk for exposure.
Residents living closest to manufacturing plants and factories reap the most adverse health affect, however, hazardous air pollutants effect the ozone layer which effects everyone.
EPA. (2009, December 29). Retrieved January 15, 2011, from Toxicity and Exposure Assessment for Children's Health: http://www.epa.gov/teach/
CBT allows the patient to control and change his or her thoughts by changing his or her specific behaviors. There are two parts to CBT, exposure and response prevention. Exposure forces a patient to “stay in contact” with the objects; for example, a person with a fear of germs might hold a dirty dollar bill for an extended period of time. Response prevention ensures that a person does not perform the ritual he would normally; for example, after holding the dollar, he is not allowed to wash his hands. CBT is free of side effects but it does increase a patient’s anxiety level. I believe psychotherapy will work well for patients because it forces them to confront their fears and over an extended period of time. This guarantees the patient faces
Stephania A. Cornier, S. L. (2006). Origin and Helth Impacts of Emissons of Toxic By-Produts and Fine Particles from Combustion and Thermal Treatment of Hazardous Wastes. Environmental Health Perspectives, 810-817.
Australian Bureau of Statistics, 2012, ABS Personal Safety Survey 2012, cat. p. 113. no. Then you can use the. 4906.0, ABS, Canberra, Table 21-33.
type of exposure there is reliable information on (Sray 49). The bill requires all pesticides to be
Professor’s comment: This student’s research paper synthesizes the results of a well-selected group of articles that explore relationships between asthma and air pollution. That laboratory science is at base a social enterprise is nicely exemplified by the focus of the studies she reviews. In drawing from the articles she reviews and in organizing her paper, the student maintains a good balance between discussing air-borne pollutants themselves and their physical effects, between analysis and implication. The result is a readable and interesting explanation of current work on this increasingly important subject.
Hazardous materials can be important in everyday life when properly handled. However, when improperly handled, they can result in injury, death, and destruction as well as have lingering effects that may last for years to come. To address the risk of an uncontrolled hazardous materials release, there must be a coordinated effort to identify, locate, and quantify the hazardous materials in a particular location (Drexel University Safety & Health, 2001). Typically, industry and government agree that a hazardous materials incident is one where
Starting with the four levels of Uncertainty, to determine the level where your industry is at, there are few factors to consider, including current clear trends, such as market demographics, and there are other factors that are currently unknown but managers can figure them out by conducting the right analysis. The uncertainty that remains after the best possible analysis has been done is called residual uncertainty. It has been
Technological and accidental hazards can be occur without warning and can be both hazardous material incidents and failures at nuclear power plant. In some cases, victims that have been exposed to harmful chemicals or radiation show little to no symptoms until several years later. There are an increasing number of new substances and chemicals being manufactured which has increased the likelihood of a hazardous material spill or release. This also increases the risk to the environment and to the health and safety of a community.
Wildavsky, A. (1995). But is it true? A citizen’s guide to environmental health and safety issues. Cambridge, MA: Harvard University Press.