Suppression of phagocytic cell responses by conidia and conidial products of Aspergillus fumigatus.

This chapter reviews the factors to be considered in health-related aerosol measurement. These factors include not only the level of initial challenge but also the time-dependent history of exposure, chemical composition, and indices of biological response. Epidemiology is usually concerned with relating the two extremes of this chain of processes since it is the disease at one end which is the “problem” and exposure at the other end which can be monitored and controlled. Risk assessment requires knowledge beyond that relating to just the mass deposited. It also requires consideration of the kinetics of how particulate material deposited in the lung is cleared and the rate at which “harmfulness” is transmitted to tissue. Aerosol measurement for risk assessment is concerned with particle size-selective sampling within the framework of a sampling strategy designed to match the kinetics of the health effect under consideration.