Suspended particulate matter (SPM) are finely divided solids or liquids that may be dispersed through the air due to combustion processes , industrialactivities or natural sources.
There is a wide range of minute particles in the air that can be seen only using an electron microscope. They include sulphates, nitrates, black carbon, particle-bound water, metals (cadmium, copper, nickel, zinc) and hydrocarbons. In addition, biological components such as allergens (pollen, dust mites)and microbial compounds (fungi) are also PM.
PM10: inhalable particles, with diameters that are generally 10 micrometres.
Standard Values of SPM According to the National Ambient Air Quality Standards of the Central Pollution Control Board (CPCB) of India, the 24-hour average for PM10 is 100micrograms/cubic metre and 60 micrograms/ cubic metre for PM2.5.