Neil C. Hawkins

A PROPOSAL FOR IMPROVING THE ROLE OF EXPOSURE MODELING IN RISK ASSESSMENT

This paper explores the adequacy of using currently available exposure assessment models for indoor air inhalation exposures in the context of the uncertainty that exists in both the dose-response assessment and the exposure assessment. A tiered system is proposed for implementing exposure assessments. Each tier involves additional research, but also would lead to reductions in uncertainty. The authors discuss a possible comprehensive research program that will permit the building of well-validated models for indoor air inhalation exposures among classes of chemicals, building types, and exposure scenarios. The authors believe that until such a research program is undertaken, modeling of exposures (and therefore risks) using the current, unvalidated modeling approaches provides little more than worst-case estimates that are useful primarily for making screening decisions about risks.

A rationale and framework for establishing the quality of human exposure assessments

Exposure assessments, performed as input to an evaluation of potential human health risk, are an element of risk assessment. Risk assessment results feed governmental and corporate risk management decisions, which seek to balance the estimated potential human health risks with other factors. Risk managers presume that the risk information provided to them is scientifically valid and accurate. Government agencies have begun to apply a system known as good laboratory practices (GLP) to ensure adequate data quality on animal studies, which are often the first step in the health-effects evaluation of risk assessment. This paper explores a rationale and framework for establishing the quality of human exposure assessments and proposes a set of good exposure assessment practices (GEAP). The components of the proposed GEAP include the writing of a study protocol before conducting the study, consideration of available resources, specification of an exposure model, a study design (including sampling and analytical methods and data analysis), quality assurance, archiving, communications, and a statement of overall uncertainty in exposure estimates. The GEAP concept is offered as a starting point for developing a consensus among the community of exposure assessors regarding a minimum standard for good practices. If a consensus on GEAP can be reached and applied, exposure assessments would have improved scientific bases, interpretability, and utility.

Creating the Future We Want

Abstract Although the world faces serious environmental, economic, and social challenges, we believe that a combination of science and innovation, effective governance, and public-private collaboration can help to overcome many of them and achieve sustainable development. Numerous government policies are now promoting sustainable management practices, while many people in the business and financial communities view sustainability as a means to reduce long-term risk, enhance competitiveness, and promote social well-being. Advances in science and technology are creating new economic opportunities and producing sustainable solutions, while expanded public access to global data and information is helping to shape business and government policies. Looking ahead, sustainability will be best pursued by building on these trends and encouraging new collaborative initiatives among governments, businesses, and the nonprofit sector. This article is an example of a collaboration that includes government, business, academic, nongovernmental, and international organizations.

EFFECTS OF SELECTED PROCESS PARAMETERS ON EMISSION RATES OF VOLATILE ORGANIC CHEMICALS FROM CARPET

There has been increased interest over the last several years in issues related to indoor air quality. Although the factors affecting indoor air quality are recognized to be very broad, ranging from building design, operation, and ventilation to biological contamination, recent emphasis has been placed on chemical contaminants, particularly volatile organic chemicals (VOCs). New floor covering systems, including new carpets, have been identified as a potential, short-term source of VOCs in the indoor air of new or renovated buildings. This report describes an exploratory study designed to examine several manufacturing variables and their effects on VOC emission rates from new carpets. It was based on a statistical experimental design and was conducted at a single carpet mill on a full-scale production line. The outcome variable, VOC emission rate, was examined relative to selected independent variables: latex type, latex amount, makeup air into the drying oven, residence time in the drying oven, and their interactions. Significant variables were identified for a number of emission rate models. The study results suggest that there are no simple answers for easily reducing VOC emission rates, but several conclusions could be inferred from the study as to future directions to pursue.

Exposure Database Improvements for Indoor Air Model Validation

Abstract Recent research in the area of public health has identified indoor and near-field exposure as typically dominant sources of airborne, low level exposure to people. Historically, the answer to the specific questions about, “What is in this buildings or that rooms air?” have been accomplished by direct measurement of the airborne concentrations. If an exposure studys sample (i.e., the number of different locations of the same class) is large enough and representative enough, then some conclusions can be made about the exposures in that class of building. Given finite resources, one could argue that we will probably never have sufficient means to adequately sample (by direct measurement) the universe of human exposures for each microenvironment of importance. The scientific community will continue to investigate and seek to understand and develop the science of contaminant source generation and control. As part of this critical activity, mathematical exposure models need to be developed and used ...

Statistical Control Charts: A Technique for Analyzing Industrial Hygiene Data

Abstract Industrial hygienists are often confronted with decisions regarding the acceptability of monitoring or other types of data. Professional judgment is used most often to make these evaluations, but some industrial hygienists are now beginning to apply more rigorous, quantitative methods such as statistical data analysis. In cases where monitoring data have been collected sequentially with a structured sampling plan, the statistical control chart may be a suitable method for evaluating results. Control charts facilitate the evaluation of time trends in data and allow the industrial hygienist to identify changes in the levels over time and in the variability of data gathered in monitoring campaigns. While a useful tool in some situations, control charting has some limitations as applied to industrial hygiene data. These limitations are discussed.

Response to Creating the future we want

“Creating the Future We Want” by Alan Hecht et al. presents a policy approach designed to address a range of social, economic, and environmental issues, grouped under the heading of sustainability. The approach is a version of “doing good by doing well” (Bonini & Mendonca, 2011). It emphasizes alignment of interests and actions between government and business. The opening paragraph conveys the article’s tone:

An Overview of Cancer Risk Assessment

Risk assessment is broadly used as a regulatory tool by a number of federal and state agencies. There has, however, been some controversy surrounding the broad application of the methodology to the protection of human health and the environment. Some of this controversy results from the uncertainties in the process, whereas other issues deal with the overall relevance of the tool. As new environmental legislation comes before congress, and existing laws come up for reauthorization, the use of risk assessment sometimes becomes an element of public debate in an arena where the methodology is not well understood. The purpose of this article, therefore, is to present an overview of the technical aspects of the process.