Paint, Ink, Varnish
The paint, ink, and varnish industries are deeply affected by the issue of particle inhalation risk, because many raw materials in powder form are integrated into products. Many pigments that have long been used exist in nanomaterial form, while newer substances are also incorporated to make formulas stronger, pollution-resistant, self-cleaning, conductive, etc.
Information related to particle size provides a different kind of insight into the perceived dangerousness of substances, but does not necessarily mean deep changes are needed to prevention strategies. The type of substances and actual exposures must be taken into account when interpreting and setting targets.
The complexity of particle mixtures present in air involves the use of high-level selective techniques, like PARTICLEVER.
When stored together, nanoparticles aggregate and agglomerate to form micrometer-scale particles. The latter kind, as they are assemblies of nanoparticles, must be understood as nanoparticulate matter. The aggregation and agglomeration states are such that isolated particles smaller than 100 nm are often negligible anyway (in terms of mass or numbers). If there is any doubt as to whether a substance contains nanoparticles, the only way to measure is to look at the particles under an electron microscope.
Although it is obvious that handling liquid nanomaterials entails lower risks (except for spraying processes), it is not totally free of them. The main issue in such cases comes in drying phases, during which the material will be deposited on walls in a potentially concentrated way. If the deposit is large, the material might become suspended in air again, and dermal exposure also needs to be taken into account.