Total Suspended Particulates

Total suspended particulates (TSP) are solid matter or liquid droplets from smoke, dust, fuel ash, or condensing vapours that can be suspended in the air. They either come from natural sources such as the sea (wind-blown sea-salt) and soil (wind-blown soil particles) or from man-made sources such as diesel exhausts, construction activities and factories. TSPs include a range of different sized particles. The coarser particles are 50-100 micrometres (where 100 micrometres is the thickness of a human hair) and finer particles are smaller than 10 micrometres in diameter.

They represent a broad class of chemical particles and may include inorganic fibres, trace metals (such as lead) and a variety of organic materials. TSP may originate from combustion, forming hydrocarbons, or from sulphates and nitrates formed during sulphur dioxide or nitrogen dioxide emissions.

Particulates can be inhaled but larger particulates can be filtered by the upper respiratory tract. Smaller particulates (respiratory suspended particulates) can enter deeper into the lungs.