aerosol - particles dispersed in a gas.

aliquot - a subsample drawn from a larger sample.

alpha-emitting - producing ionizing radiation in the form of alpha particles.

anthropogenic - referring to environmental alterations resulting from the presence or activities of humans.

actinides - the series of radioactive elements that starts with actinium and ends with lawrencium.

aerodynamic diameter - distance around a sphere of unit density with the same settling velocity as the particle size of concern.

attenuation - the reduction in level of a quantity, such as the intensity of a wave, over an interval of a variable, such as the distance from a source.

coefficient of variation - a statistical parameter that expresses standard deviation as a percentage of the mean, calculated as standard deviation divided by the mean, multiplied by 100.

Compton continuum - energy levels in the response of a photon spectroscopy instrument corresponding to scattered electrons.

dosimetry - the measurement of radiation doses.

gamma-emitting - producing ionizing radiation in the form of gamma rays.

gross alpha - measurement of total number of alpha decays without specification of individual energies

in vivo - taking place in a living cell or organism.

informatics - information management systems.

kiloelectronvolts - a unit of energy, equal to 1,000 electronvolts.

lumen - a unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source of one candle intensity.

multi-channel analyzer - a device that convert successive electronic signals into parallel amplitude channels.

photon - a massless particle, the quantum of the electromagnetic field, carrying energy, momentum, and angular momentum.

radionuclide - a type of atom that loses particles and energy through decay or transformation into other elements.

standard deviation - a statistical parameter, calculated as the positive square root of the expected value of the square of the difference between a random variable and its mean.

standard error - the standard deviation of the probability function or probability density function of a random variable and of a statistic.

temporal - pertaining to or limited by time.

tertiary - third level.