The NPI contains data on 93 substances that have been identified as important due to their possible effect on human health and the environment. The data comes from facilities like mines, power stations and factories, and from other sources, such as households and transport.
The NPI is tracking emissions of substances to air, land and water, and the transfer of substances, on-site or off-site, to a mandatory or voluntary reporting destination.
The substance list shows all the substances required to be reported (if a facility exceeds reporting thresholds) the relevant threshold category, and thresholds.
There are fact sheets describing the physical and chemical properties of each substance, how you might be exposed to a substance, common uses, and sources of emissions.
There also are ten fact sheets that have been developed for students.