Introduction. The city of Chita of Zabaikalsky region is one of the cities of Russia, priority on level of pollution of atmosphere. Of the order of 130 impurities emitted by the sources of the city, 12 are monitored at 5 posts of the Roshydromet network. Maximum monthly average concentrations are formed by benz (a) pyrene (up to 56.8 MPC), hydrogen sulfide (12.3 MPC), suspended particles (up to 4PDC), phenol (up to 3.6 MPC). Significant emissions (59.73 thousand tons in 2018) are aggravated by the use of coal as a fuel by heat and power enterprises and the private sector, climatic and geographical features. Within the framework of the Federal project “Clean Air” of the national project “Ecology”, it is envisaged to reduce the gross emission of pollutants into the atmosphere of Chita by 8.75 thousand tons by 2024, which should lead to a significant improvement in the safety and quality of life of citizens. It is necessary to identify the most “risky “components of pollution for health.It is important to understand: whether the environmental monitoring system reflects the real picture of the dangers posed by pollution of the city’s atmosphere; whether there is a need to optimize the monitoring system for the subsequent assessment of the effectiveness and efficiency of measures; what impurities and at what points should be monitored in the interests of the population, administration and economic entities implementing air protection measures.The aim of the study is to develop recommendations for optimizing the program of environmental monitoring of air quality in the city of Chita, taking into account the criteria of danger to public health for the subsequent evaluation of the effectiveness and effectiveness of the Federal project “Clean Air”.Materials and methods. Justification of optimization of monitoring programs was carried out through the calculation of hazard indices, considering: the mass of emissions and toxicological characteristics of each chemical; the population under the influence. A vector map of the city with a layer “population density” was used as a topographic base. The indices were calculated for regular grid cells covering the residential area. For each cell, the repeatability of winds of 8 points from the priority enterprises and the population within the calculated cell were taken into account. As a result, each calculation cell was characterized by a total coefficient, taking into account the danger of potential impacts of emissions. Based on the results of the assessments, recommendations were formulated to optimize the placement of posts in the city and the formation of monitoring programs.Results. Indices of carcinogenic danger to the health of the population of Chita ranged from 584,805. 96 to 0.03 (priorities: carbon (soot), benzene, benz (a) pyrene); indices of non-carcinogenic danger — from 1,443,558. 24 to 0.00 (priorities: sulfur dioxide, inorganic dust containing 70–20% SiO2, fuel oil ash). The greatest danger to public health stationary sources of emissions form in the North-Western, Western and South-Eastern parts of the city. Roshydromet posts in these zones are absent.Conclusions. As part of the objectives of the project “Clean Air”, it is recommended to Supplement the existing state network of observations of atmospheric air quality in Chita with two posts; to include manganese, xylene, vanadium pentoxide in the monitoring programs, to carry out the determination of Benz(a)pyrene et all posts, which will allow to fully and adequately assess the danger of emissions of economic entities, as well as the effectiveness and efficiency of the provided air protection measures.
The value of long-term environmental monitoring programs: an Ohio River case study