Particle surfaces Where pollutant specials are present in or associated with a condensed phase,it is necessary to establish whether the pollutant is part of the bulk system or present on it's surface. Such a consideration is particularly meaning since material present on the surface of an airborne particle,for example, comes into immediate contact with the external environment,whereas that which is distributed uniformly throughout the particularly is effectively present at a much lower concentration and can exert a much lower chemical intensity at the particle surface. Since airborne particles can be inhaled, surface predominance can result in high localized concentrations of chemical species at the points of particle deposition in the lung.

颗粒表面，在那里污染组分以浓缩态出现或者伴随。有必要去证实污染物是块本身的部分还是出现在它的表面。这种考虑特别有意义，因为出现在空气浮动颗粒表面的材料，比如说，直接接触外部环境，在整个颗粒内均匀分布，实际上在颗粒表面以一个相对低很多的浓度出现并且施加一个相对低很多的化学密度。因为在空气中浮动的颗粒可以被吸入，所以表面主导性（surface predominance）可以导致化学组分在肺部颗粒沉积点高度局部聚集。