National Athletic Trainers' Association. The certifying and governing body of the athletic training profession, as approved by the National Commission for Health Certifying Agencies.
National Association of Testing Authorities Body which accredits services which test equipment against standards.
National-Scale Air Toxics Assessment. A project undertaken by USEPA in which they estimate exposure to air toxics nationwide for 1996. It consists of an inventory of air toxics emissions from point, area, and mobile sources; dispersion modeling of those emissions to estimate ambient air concentrations; and estimates of the resulting risk to the population nationwide.