Inhalation exposure and alveolar load of nanomaterials in spray products

During use of a spray product, the nanomaterial is released and may become airborne.

Nanomaterials will generally be released as part of aerosol particles. Aerosol particles carrying the nanomaterial may be inhaled and may deposit in various regions of the respiratory tract, in particular in the alveolar region. Deposited particulate material will be removed from the alveoli by clearance (e.g. macrophage and ciliary clearance), dissolution and interstitialisation. For poorly soluble nanomaterials, all these processes are expected to be slow.

The total alveolar load of a nanomaterial at any given time is the result of competing kinetic processes of (repeated) exposure, deposition and clearance.

The magnitude of the aerosol air concentration is determined by the spray and the conditions of its use. It is in particular a result of the mass generation rate of the spray, the size (distribution) and mass density of the generated aerosol, the duration of use of the spray, ventilation of the air et cetera.

Deposition of the inhaled aerosol in the respiratory tract will depend on both aerosol characteristics and human physiology. The most important aerosol characteristics that determine deposition are the aerosol diameter and its mass density. The critical aspects of human physiology are the geometry of the lung and the breathing pattern (i.e. intensity of breathing) of the exposed person.

To model exposure and the alveolar load, ConsExpo nano combines a number of models.