On the evaluation of storage facilities on the dustiness of the urban environment

Examined the classification of dust from different storage facilities. Were considered different samples of dust (construction, textile, food), generated in storage facilities. Studied the influence of anti-dust coverage on dustiness of storage facilities as the pollution source. This paper presents the results of chemical analysis, studied dustiness, determined classification of studied dust. Constructed integral distribution curves of mass particles by equivalent diameter.


Introduction
In the production of construction materials, dust is considered to be solid particles, the size on these categories [1]: 1. Large-dispersed dust (50medium and is noticeable without the use of special devices; 2. Small-dispersed dust (20examined under a microscope at small increases; 3. Fine dust (0,1visible in standard microscopes; 4. Ultrausing an electron microscope.
There are also other classifications. Despite their diversity -it can be said, that many authors [2,3] considers dust is small-The characteristics of dust from different dispersion groups differs from each other, both in quantitative changes in the dust physical properties and in the nature of the laws expressing these changes.

Methods
Currently, in a number of countries, including Russia, the content of particles in the dispersed dust is the most dangerous, because it can get inside of human lungs. A system for monitoring and evaluating the concentration and composition of small sized particles in storage facilities is currently absent, which does not allow to give an objective evaluation of the dust influence on the quality of the working environment and air emissions.
The aim of the research is to improve the evaluation of storages as a source of dust pollution of the environment, to develop, based on the acquired data, measures to improve the ecological safety of these premises.
To achieve this goal the following tasks were solved: Determination of the dust small fractions concentration of non-production storages influence of anti-dust coverage on dustiness of the environment near storages; The storage as the source of pollution has some dust emission zones, through which dust, subsided on the floor and service platforms, released in the environment. These include deflectors, various openings in the room and aspiration systems in the presence of technological operations (packaging, overfilling, etc.).
In order to evaluate the pattern of air pollution near storage facilities, was used the method of determining the concentration and dispersal composition of dust inside and outside storages. Measurements of dispersal composition and concentration of dust were carried out in accordance with normative documents [4][5][6][7]. Several points of dust concentration measurements points were chosen. The points were in unloading/loading zone. Also, was considered further distribution of harmful substances from the windward and leeward sides. Since a loading-unloading works zone is unorganized source of pollutants emission, to calculate the dust emission volumes were used the following formulas: M = (k1 k2 k3 k4 k5 k7 k8 k9 G 10 6 ) / 3600, g/sec (1) M = (k 4 k 5 k 6 k 7 q F ) + ((k 4 k 5 k 6 k 7 0,11q (F -F ) (1-)), M = (k1 k2 k3 k4 k5 k7 k8 k9 G 10 6 ) / 3600, g/sec Where the ratios, used for calculations during unloading, storage and loading, are taken from the methodical guide [8]. Further, with the help of the program UPRZA "Ecologist" (Fig. 1) were giving the coordinates for the source of dust emissions from the storage during the loading-unloading works, and also, the coordinates of points at the distance from were acquired in the points of given coordinates. Based on the acquired data, the distribution picture of the dust emission concentration from the storage in the loading-unloading zone, was constructed (Fig. 2).  Defined the total and fractional dust concentrations. Constructed integral distribution m values for PM10 and PM2,5: where C -total dust concentration in researched point, mg/m 3 , PM2,5 and PM10 -concentration of dust with the size less than 2,5 m and 10 m, accordingly, mg/m 3 , F (d)-integral distribution function of particles by equivalent diameter, %, d = equivalent particle diameter [9] For determination of dispersal composition and characteristics of dust in the air of storage facilities, the microscopy method was used [10][11][12]. In this regard, was conducted the dust analysis, sampled in the atmosphere from the storages for three types of the materials. On the Fig.3 presented integral distribution functions of mass dust particles by equivalent diameter in the probabilistic-logarithmic coordinate system for storage facilities of textile, construction and food materials, in the lower and upper zones.
According to the data, acquired in the experiment and shown on Fig.3, it may be concluded, that the size of dust particles in the upper zone is a lot smaller, then in the lower zone. For textile dust d50 50 m (in the lower zone); for food dust d50 50 construction dust d50 50 In the course of the research, was implemented the chemical analysis of construction materials dust, with the subsequent micro-X-ray analysis. The analysis was performed on optical microscope 3D Versa. With the use of this microscope, were measured the sizes of construction dust particles with different zoom. For comparison were chosen samples of some representative dust samples from the storage. In composition of all samples were found silicates and carbonates of alkali and alkaline earth metals, sodium chloride, iron oxide and molybdenum oxide, and aluminum oxide. Silicon oxide prevails. The composition is close to bauxite, this is confirmed by stored material in the storages -brick. The size of a small particles (Fig. 3) varies from 0,6 for example, during the technological operations (packing, overfilling, cutting, and etc.). Dust of this size causes significant harm to workers in this room, also, it is taken outside of the storage. Consequently, it becomes necessary to install additional dust collectors. The research, conducted near storages for food, construction and textile, allowed to obtain data on distribution of dispersal dust composition during at different wind directions relatively to the storage (leeward and windward sides), and with an anti-dust coverage, and without it. As an example, the Fig. 4 and 5, show the results of the studies for the distribution function of construction and food dust. According to the acquired data, for both types of storages, in the air from windward side the particles of dust were larger, because, mostly -it is urban and roadside dust.

Results and Discussion
Research, conducted for storages with anti-dust coverage in the unloading/loading zone of materials (Fig.5) showed, that in this case the percentage of small-dispersed dust of PM10 drastically increases (to 100 %). Nevertheless, the total and integral fractional concentration in storages with anti-dust coverage is smaller.
The conducted studies allowed to analyze the ratio of the dust dispersal composition of harmful substances in the air from the leeward and windward sides of the storage, near to the sanitary protection zone with the existence and absence of anti-dust coverage. Nevertheless, the wind with the speed 3-6 m/s was bringing large dust from the windward side (from the sanitary protection zone) of the road. And on the other side (leeward side)small dust. Accordingly, with the existence of anti-dust coverage in storages, smalldispersed dust is more prevalent. The proportion of construction materials on leeward and 10 and less, in the air of the working zone is 100 % from the total mass of dust. The content of dust on the leeward and windward sides without anti- 10 and less, in the air of the sanitary protection zone is 0,5 % from the total mass of dust. The content of dust with the 2,5 in the storages without anti-dust coverage is absent. In the storages with anti-2,5 particles are approximately an equal and amounts to 3 % of the total mass of dust.
Similarly, based on the research given by the author, the content of food dust on leeward and windward sides without anti- 10 and more in the air of the working zone is 99 % from the total mass of dust, with anti-dust coverage on the windward side is 70 %, on the leeward side -8 %. Other -large particles. The content of dust on the leeward and windward sides without anti- 2,5 in the air of the sanitary protection zone is absent. The content of dust on the leeward side with anti-2,5 is less than 1%, on the windward side -0,3 %. At high wind speed 6-12 m/s the picture changed. Large-dispersed dust did not settle in the SPZ of the storage, therefore, the concentration at the border of the sanitary zone of the storages increased (to 30 %), then on the windward. The proportion of small-dispersed dust increased PM10 (to 26 %). The proportion of PM2,5 in all studies did not exceed 5 %.

Summary
The results of the experiment showed, that the largest percentage of dust removal from the storage depends on the humidity index, wind speed and particle size. Furthermore, was studied the influence of dust removal from storages on the dustiness of the environment.
Dust size depends on the side of the storage relatively to wind and from existence of anti-dust coverage.
In addition to meteorological parameters, the acquired results are also influenced by the density, size and sorbing properties of particles, as a result -the influence of total dust concentration on the content of small fractions in residential area, which are located near the industrial enterprises, requires further study.
The classification of studied dust is determined. For all types of storages the dust, from the windward side, as a rule, is smaller.