Figures
- FIGURE 1
Pathogenesis of dust particulate matter (PM)-associated occupational lung diseases. Schematic shows the entry of particulate matter (PM10 and below) through environmental/occupational exposure into lungs and development of subsequent respiratory complications, which include increased cellular influx (macrophages, neutrophils, T-lymphocytes and B-cells), alveolar destruction (emphysema) and structural changes (collagen and mucus deposition) leading to chronic bronchitis. PMx: particles with a 50% cut-off aerodynamic diameter of x µm; CWP: coal worker's pneumoconiosis.
- FIGURE 2
Mechanisms of dust particulate matter (PM) toxicity. Schematic representation depicting ambient airborne PM with various cellular mechanisms and triggering cascade reactions, i.e. cellular inflammation, reactive oxygen species (ROS) and reactive nitrogen species (RNS) production, cytokine production and DNA damage, leading to cell death and scar tissue formation. Created with BioRender.com. IL: interleukin; NF-κB: nuclear factor-κB; TNF: tumour necrosis factor.
- FIGURE 3
Pathogenesis of reactive crystalline silica (RCS). The illustration depicts the interaction of RCS with lung epithelial cells and subsequent activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome pathway and production of pro-inflammatory cytokine interleukin (IL)-1β, free radicals and fibroblast-activating factor leading to fibrosis. Created with BioRender.com. ROS: reactive oxygen species; RNS: reactive nitrogen species; ASC: apoptosis-associated speck-like protein containing a caspase activation and recruitment domain; TNF: tumour necrosis factor; NF-κB: nuclear factor-κB.
- FIGURE 4
Occupational exposure limits (OELs) of a) silica (quartz) and b) coal dust particulate matter (PM). The graphs show that the OEL or safe dust exposure limits of respirable and inhalable fractions of silica and coal dust PM vary significantly among different coal-producing countries. These limits are set primarily on particle size. TWA: time-weighted average; ACGIH: American Conference of Governmental Industrial Hygienists; NIOSH REL: National Institute for Occupational Safety and Health recommended exposure limit; OSHA PEL: Occupational Safety and Health Administration permissible exposure limit; TLV: threshold limit value; MSHA: Mine Safety and Health Administration.
Tables
- TABLE 1
Safety standards of particulate matter (PM) in ambient air in different geographical areas
Agency PM10 PM2.5 Reference World Health Organization (2018) 20 μg·m−3 (annual)
50 μg·m−3 (24-h)10 μg·m−3 (annual)
25 μg·m−3 (24-h)[2] US Environmental Protection Agency 50 μg·m−3 (annual)
150 μg·m−3 (24-h)12 μg·m−3 (annual)
35 μg·m−3 (24-h)[28] New South Wales Environment Protection Authority (Australia) 25 μg·m−3 (annual)
50 μg·m−3 (24-h)8 μg·m−3 (annual)
25 μg·m−3 (24-h)[29] UK and EU UK/EU: 40 μg·m−3 (annual)
50 μg·m−3 (24-h)#UK: 25 μg·m−3 (annual) [30] Scotland: 18 μg·m−3 (annual)
50 μg·m−3 (24-h)¶Scotland: 10 μg·m−3 (annual) PMx: particles with a 50% cut-off aerodynamic diameter of x µm. #: not to be exceeded more than 35 times a year in the UK; ¶: not to be exceeded more than seven times a year in Scotland.
