Ambient Air – The air outside of structures. Often used interchangeably with “outdoor air.”
Analytical Models – Models that can be solved mathematically in closed form. For example, some model algorithms that are based on relatively simple differential equations can be solved analytically to provide a single solution.
Application Niche – The set of conditions under which the use of a model is scientifically defensible.
Bayesian analysis – An approach to statistical analysis that is based on Bayes’s Theorem, which states that the posterior probability of a parameter p is proportional to the prior probability of parameter p multiplied by the likelihood of p derived from the data collected. The Bayesian approach attempts to keep track of how a priori expectations about some phenomenon of interest can be refined and how observed data can be integrated with such a priori beliefs, to arrive at updated posterior expectations about the phenomenon. The Bayesian approach to decision making incorporates new information or data into the decision process. It allows the analyst to use both sample (data) and prior (expert-judgment) information in a logically consistent manner in making inferences. As further information becomes available, the original assumptions are refined and corrected.
Bias – Systematic deviation between a measured (observed) or computed value and its “true” value. Bias is affected by faulty instrument calibration and other measurement errors, systematic errors during data collection, and sampling errors, such as incomplete spatial randomization during the design of sampling programs.
Biologically Based Dose-Response (BBDR) Model – A predictive model that describes biological processes at the cellular and molecular level linking the target organ dose to the adverse effect. BBDR models predict dose-response relationships on the basis of principles of biology, pharmacokinetics, and toxicology.
Boundaries – The spatial and temporal conditions and practical constraints under which environmental data are collected. Boundaries specify the area or volume (spatial boundary) and the time period (temporal boundary) to which a decision will apply.