Let us recall that the current Hygienic Standards for atmospheric air in urban and rural settlements, on the territories of industrial organizations were approved on August 2, 2022. They indicate the maximum permissible concentrations of pollutants.
For example, for carbon monoxide (aka carbon monoxide), the maximum one-time MPC is 5 mg per cubic meter of air. More is dangerous to health and even life. But the problem is that a smaller amount is also dangerous. If, in addition to carbon monoxide, there are other harmful substances in the air that act in the same direction , that is, they have a similar effect and cause the same diseases.
For example, hexane is a relatively safe and easily evaporating solvent. The maximum permissible concentration for it is as much as 60 mg per cubic meter of air.
If we count them separately, as was done before, then formally the concentration of MPC of these substances in the air may be within the norm. However, in reality the harm will be unacceptable, since their MPCs must be summed up.
This, that is, taking into account the summation effect , is the subject of the order of the Minister of Health of the Republic of Kazakhstan No. 10 on amendments and additions to the Hygienic Standards.
This supplement is a list of substances that have a summation effect. And also a calculation formula.
On March 7, 2025, the new rules will come into effect.
https://www.zakon.kz/pravo/6469552-dyshat-stanet-legche-k-soderzhaniyu-vrednykh-veshchestv-v-vozdukhe-predyavlyayut-novye-trebovaniya.html