Dust – Trojan Horse of working environment? - Riga Stradiņš University

Dust – Trojan Horse of working environment?

11:45, 09 September, 2015
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Dust or particulate matter, usually abbreviated as PM, of different sizes is a part of our everyday life. Is there anyone who has not complained about the dust? Dust is in the indoor air and in the air of the surrounding environment, and the main sources of it are mostly man-made. For example, vehicle exhaust gases or emissions of manufacturing and heating systems, or more modern and less known sources of dust as emissions created by copying machines and printers consisting of very small dust particles (see Picture 1). Of course, dust can originate and actually originates from any other solid substance. The most frequently controlled dust in the surrounding environment is the dust having the largest effect on health. Due to its size, this kind of dust can get into our lungs (PM10 and PM2.5 – particles with a diameter of 10 and 2.5 µm). People intake these dust particles by inhaling them, however, the issue on the intake of particles of substances dermally, for example, by using various cosmetic products (sunscreen etc.) has become more topical nowadays.

dust 1For centuries, people have been concerned whether inhalation of dust is harmful. The danger posed by dust is mainly determined by the size, shape (round, edgy etc.) and chemical composition of these particles. Dust of irregular shape with chemical activity and small size is the most dangerous for health. Nowadays, more serious concerns arise specifically from very small-sized dust particles (also known as nanoparticles, as their size is smaller than 0.1 µm or 100 nm), since these particles can remain in the air for long period of time, and after inhaling them, these particles are able to penetrate deep into lungs and then spread via blood throughout the entire body and accumulate in the walls of blood vessels, lymph nodes, brain, liver and other organs – dust of larger size does not have such ability. It has to be noted that in recent years the use of nanoparticles has increased significantly – nowadays, almost everyone of us comes into contact with these particles (for example, vehicle emission, cosmetics, equipment coating etc.).

Under normal conditions, human body successfully deals with the amount of inhaled dust, however, in situations when the dust concentration is very high or for persons suffering from chronic lung diseases, by inhaling dust, including nanoparticles, the health condition may deteriorate and dust can provoke worsening of the course of chronic disease, for example, cause an asthma attack. Therefore, it is important to control the level of pollution caused by dust particles in the indoor air and in the air of surrounding environment.

However, in household situations high concentration of dust usually occurs very rarely. In the working environment, dust can be detected more frequently while performing specific working processes, for example, by grinding or polishing any kind of material, performing welding works, painting with powder paints or making nano-coatings for surfaces, we can expose ourselves to significant amounts of dust.

While scientists and doctors have learned to determine the concentrations of simple dust particles and estimate their effect relatively well, still risk caused by nanoparticles is yet to be assessed. The wish to study detection, effect and risks caused by nanoparticles was the main guiding principle while implementing the project “Development of Modern Diagnostic and Research Methods for the Risks Created by Nanoparticles and Ergonomic Factors in Workplaces”, co-financed by the European Social Fund. Within the framework of this project, studies were conducted in the working environment and several guidelines and methodologies were developed.

The most significant problem is that by observing the working process visually it is impossible to distinguish whether very small dust particles or nanoparticles are “hiding” in the dust. Therefore, it is necessary to use special equipment which helps to “sort”, “count” and “measure” dust particles according to their size and mass (weight) (see Picture 2), and to use microscopes that can “decode” the content, size and shape of dust particles.

dust 2Of course, it is important not only to learn how to measure nanoparticles, but also to understand in which workplaces there are more of them and what are their features. During the project, while assessing the air quality in an office (pollution of the surrounding environment, emission of copying machines and printers etc.), metal processing (welding processes) and wood processing (grinding processes) companies, dust samples were obtained, the analysis of which showed that nanoparticles can be found in the air of working environment of these companies. In addition, it has to be noted that shapes of these particular nanoparticles were both spherical and edgy (see Picture 3), and their chemical composition was very complex – we detected presence of silicon, manganese, zinc, chrome and other chemical elements that may strengthen the overall adverse effect of dust on the health of employees, since the effect of zinc, manganese and chrome on the human body is more toxic.

dust 3Overall, the lowest concentration of nanoparticles was observed in the office, whereas the highest – during the welding process (17 times higher than in the office), as well as during the wood grinding process (8 times higher than in the office). Regarding the risk caused by nanoparticles and other types of dust, it shall be kept in mind that it is very important to ensure efficient operation of ventilation systems and their proper use, because the traditionally used respirators (gas masks) are not efficient against nanoparticles, as the size of pores of materials used in these respirators is larger than 0.1 µm or 100 nm, thus they are not able to block nanoparticles. The fact that ventilation systems in companies are not always operating efficiently enough and the effect of nanoparticles on human health can be negative, is also proved by health condition data that were obtained by performing nasal lavage and taking nasal mucous membrane smears and blood analysis of employees. It was concluded from the data that penetration of nanoparticles into cells causes increased inflammatory response.

Without implementing any changes or changing their existing job for a less dusty job with lower concentration of nanoparticles, these employees are more likely to suffer from bronchitis, pneumonia, and dust initiated diseases (pneumoconiosis), bronchial asthma can develop. Also the possibility of oncologic diseases is not excluded.

Everyone can at least slightly influence the level of pollution caused by dust particles in the surrounding environment and the working environment by choosing environmentally friendly materials and technologies, and observing safe working methods, thereby saving the environment, their own health and the health of other people.

This article has been prepared in cooperation with the specialists of the Institute of Occupational Safety and Environmental Health of Rīga Stradiņš University within the framework of the project “Development of Modern Diagnostic and Research Methods for the Risks Created by Nanoparticles and Ergonomic Factors in Workplaces” (Agreement No 2013/0050/1DP/

Rīga Stradiņš University, 16 Dzirciema Street, Rīga, LV-1007, Latvia, +371 67409261 (UTC +2), international@rsu.lv