Estimating Respirable Dust Exposure from Inhalable Dust Exposure

Abstract

In the sector of occupational safety and health only a limited amount of studies are concerned with the conversion of inhalable to respirable dust. This conversion is of high importance for retrospective evaluations of exposure levels or of occupational diseases. For this reason a possibility to convert inhalable into respirable dust is discussed in this study. To determine conversion functions from inhalable to respirable dust fractions, 15 120 parallel measurements in the exposure database MEGA (maintained at the Institute for Occupational Safety and Health of the German Social Accident Insurance) are investigated by regression analysis. For this purpose, the whole data set is split into the influencing factors working activity and material. Inhalable dust is the most important predictor variable and shows an adjusted coefficient of determination of 0.585 (R2 adjusted to sample size). Further improvement of the model is gained, when the data set is split into six working activities and three material groups (e.g. high temperature processing, adj. R2 = 0.668). The combination of these two variables leads to a group of data concerned with high temperature processing with metal, which gives rise to a better description than the whole data set (adj. R2 = 0.706). Although it is not possible to refine these groups further systematically, seven improved groups are formed by trial and error, with adj. R2 between 0.733 and 0.835: soldering, casting (metalworking), welding, high temperature cutting, blasting, chiseling/embossing, and wire drawing. The conversion functions for the seven groups are appropriate candidates for data reconstruction and retrospective exposure assessment. However, this is restricted to a careful analysis of the working conditions. All conversion functions are power functions with exponents between 0.454 and 0.946. Thus, the present data do not support the assumption that respirable and inhalable dust are linearly correlated in general.

Occupational Exposure to Mineral Dust in Mining and Earthmoving Works: A Scoping Review

“…Of the analysed studies, only one [43] was conducted in a construction-site environment; all other studies concerned mines or quarry sites. The exploited materials were, from the most commonly to least commonly exploited: coal [6,22,[30][31][32]41,44,52,56], iron [25,42], limestone [28,53], aggregates [24,51], taconite [47], granite [46], sandstone [55], copper [45], gold [48], platinum [54], and manganese [25].…”

“…However, the actual settings of such exposure were not determined. It is very demanding to proceed to dust measurements within actual operating conditions due to several factors, namely: study setup and measuring points [24]; weather conditions, such as wind speed, wind direction, presence of rain, and temperature [25]; and mining method [26].…”

Sources of airborne particulate matter-bound metals and spatial-seasonal variability of health risk potentials in four large cities, South Korea

“…Inhalable dust fraction consists of particles with an aerodynamic diameter up to 100 µm (WHO 1999). Thus, the largest particles in TSP can be inhaled and deposited in the air passages between the mouth, the nose, and the larynx (WHO 1999;Wippich et al 2020). Smaller particles with an aerodynamic diameter up to 10 µm in TSP are able to form respirable fraction and reach the gas-exchange region of the lungs (ISO 7708 1995;WHO 1999;Wippich et al 2020).…”

“…Thus, the largest particles in TSP can be inhaled and deposited in the air passages between the mouth, the nose, and the larynx (WHO 1999;Wippich et al 2020). Smaller particles with an aerodynamic diameter up to 10 µm in TSP are able to form respirable fraction and reach the gas-exchange region of the lungs (ISO 7708 1995;WHO 1999;Wippich et al 2020). However, the EPA guidance used for health risk estimation in this study assumes that 100 percent of deposited dose is available for uptake into the systemic circulation or for activity in the respiratory tracts without clearance mechanisms of large particles (US EPA 2009).…”

“…( 3)) in health risk estimation via inhalation. Recently, a method of interpreting TSP data was reported using a mathematical conversion ratio between inhalable and respirable particle depending on working activity and material including metal, fiber, and mineral (Wippich et al 2020). Several studies have compared chemical compositions in different size of PM from specific emission sources (Li et al 2017;Lyu et al 2017;Tian et al 2021) and however, the exact size distributions of airborne PM or metals are not yet available due to the variety of emission sources and physicochemical changes during the aging processes of particles (Li et al 2017;Lyu et al 2017;Tian et al 2021).…”