Rationing and calculation of maximum permissible emissions of pollutants into the atmosphere

Physicochemical principles of atmospheric pollution standardization

The main physical characteristic of atmospheric impurities is concentration (mg/m3). The concentration of impurities determines the physical, chemical, and other types of impact of a substance on the environment and is the main parameter for the standardization of atmospheric pollution.

Standards for the content of pollutants in the air are maximum permissible concentrations (MPC).

MPC is the concentration of a harmful substance in the environment which, upon constant contact or exposure over a certain period of time, has practically no effect on human health and does not cause adverse consequences for their offspring.

From an ecological perspective, MPCs for harmful substances represent the upper limit of an organism's stability; if exceeded, the substance (i.e., factor) becomes a limiting one.

The most characteristic effects of harmful substances on an organism are toxic and reflex effects. This fact has necessitated the establishment of two types of MPC for pollutants:

• maximum one-time;
• average daily.

The maximum one-time MPC value must not permit reflex reactions in humans (runny nose, perception of odor, etc.). The average daily MPC must not permit toxic, carcinogenic, or mutagenic effects.

Methods for regulating pollutant emissions

When designing enterprises in areas where the ambient air is already polluted by emissions from other operating facilities, it is necessary to standardize their emissions, taking into account the impurities already present in the air (background concentration).

If there are several sources of emissions, the requirement for the air quality of a settlement is as follows:

max i ≤ MPC − Cb, (6.1) where Cmax i is the maximum concentration of a harmful substance in the air of a settlement from the i-th source; Cb is the value of the background concentration; N is the number of sources from which the substance enters the air.

In the presence of emissions of several substances possessing a summation effect, the conditions of sanitary standards will be met if

To regulate the emission of harmful substances into the atmosphere, individual standards for maximum permissible emissions (MPE) are used for each substance and enterprise, which take into account the number of sources, their height, the distribution of emissions in time and space, and other factors.

Maximum permissible emissions constitute the limit quantity of a harmful substance allowed for emission from a given source that does not create a ground-level concentration dangerous to humans, livestock animals, and plants. MPE is a calculated value determined by formulas and using special computer programs. Each enterprise must have a list (volume) of MPEs approved by the local environmental protection authority.