Inhalable Particulate (PM10) Emission Externalities From Overburden Dumps and Associated Health Risk Assessment in Densely Populated Coalfield

Overburden (OB) dumps and associated haulage are the significant contributors to increased respirable particulate levels in mining areas. Earlier studies have only focused on reporting seasonal variation of size-segregated particle mass concentration, limiting the role of specific emission sources on sensitive receptors nearby. This study estimated the impact of OB dump expansion (between years 2016 to 2018) with associated haulage on spatial pattern of particulate concentration, associated health effects, and health cost. Furthermore, a model to identify critical health risk zones was also developed. Haulage of OB and its unloading contributed to a significant increase in particulate concentration on the windward side. Moreover, OB dumping resulted in a higher respiratory dose for workers and inhabitants nearby the OB dumpsite. The results indicated that coughing along with lower respiratory problems were the dominant health effects. Moreover, the cases of lower respiratory symptoms due to PM10 emissions from OB dumps increased in 2018. The risk potential model indicated a 4.9% increase in high risk category for population exposed to PM10 emission from OB expansion within two years. An alternative management option was proposed to reduce health risk potential. The control resulted in 73% peak concentration curtailment and 84% reduction in the surface area exceeding prescribed PM10 (100 µg/m3) levels. The said study will be useful in demarcating risk zones and findings have particular significance for dispersion of particulates emanating from OB dumps.

The Development of Strategies to Reduce Exhaust Emissions from Passenger Cars in Rzeszow City—Poland. A Preliminary Assessment of the Results Produced by the Increase of E-Fleet

Urban agglomerations close to road infrastructure are particularly exposed to harmful exhaust emissions from motor vehicles and this problem is exacerbated at road intersections. Roundabouts are one of the most popular intersection designs in recent years, making traffic flow smoother and safer, but especially at peak times they are subject to numerous stop-and-go operations by vehicles, which increase the dispersion of emissions with high particulate matter rates. The study focused on a specific area of the city of Rzeszow in Poland. This country is characterized by the current composition of vehicle fleets connected to combustion engine vehicles. The measurement of the concentration of particulate matter (PM2.5 and PM10) by means of a preliminary survey campaign in the vicinity of the intersection made it possible to assess the impact of vehicle traffic on the dispersion of pollutants in the air. The present report presents some strategies to be implemented in the examined area considering a comparison of current and project scenarios characterized both by a modification of the road geometry (through the introduction of a turbo roundabout) and the composition of the vehicular flow with the forthcoming diffusion of electric vehicles. The study presents an exemplified methodology for comparing scenarios aimed at optimizing strategic choices for the local administration and also shows the benefits of an increased electric fleet. By processing the data with specific tools and comparing the scenarios, it was found that a conversion of 25% of the motor vehicles to electric vehicles in the current fleet has reduced the concentration of PM10 by about 30% along the ring road, has led to a significant reduction in the length of particulate concentration of the motorway, and it has also led to a significant reduction in the length of the particulate concentration for the access roads to the intersection.

The Effects of Virgin and Recycled PA12 Powders in SLS Processes on Occupational Exposures

Particulate matter and ultrafine particles are emitted during the pre-processing and post-processing activities of selective laser sintering (SLS) processes, which is major concern to operators exposed to the powders. This study aims to determine the occupational exposure (in terms of the total particle concentration and respirable particulate concentration) during the pre-processing and post-processing activities of SLS processes using virgin and recycled polyamide 12 (PA12) powders. Personal air sampling was performed for each activity according to the NIOSH 0500 and NIOSH 0600 methods. Based on the results, both powders were uniform spheres with a particle size of 40–60 μm. The total particulate concentration was most significant during the following pre-processing activities: 1) pouring powder into the mixing machine and 2) transferring the powder to the SLS AM machine. The total particulate concentration and respirable particulate concentration were slightly higher for the virgin powder for these activities. In conclusion, the virgin and recycled PA12 powders were both inhalable and respirable, which poses serious health hazards to the SLS AM operators. Hence, it is essential for operators to use suitable personal protective equipment (including respirators) and the working practices need to be improved by automating

A foehn-induced haze front in Beijing: observations and implications

Despite frequent foehns in the Beijing–Tianjin–Hebei (BTH) region, there are only a few studies of their effects on air pollution in this region, or elsewhere. Here, we discuss a foehn-induced haze front (HF) event using observational data to document its structure and evolution. Using a dense network of comprehensive measurements in the BTH region, our analyses indicate that the foehn played an important role in the formation of the HF with significant impacts on air pollution. Northerly warm–dry foehn winds, with low particulate concentration in the northern area, collided with a cold–wet polluted air mass to the south and formed an HF in the urban area. The HF, which is associated with a surface wind convergence line and distinct contrasts of temperature, humidity and pollutant concentrations, resulted in an explosive growth of particulate concentration. As the plain–mountain wind circulation was overpowered by the foehn, a weak pressure gradient due to the different air densities between air masses was the main factor forcing advances of the polluted air mass into the clean air mass, resulting in severe air pollution over the main urban areas. Our results show that the foehn can affect air pollution through two effects: direct wind transport of air pollutants, and altering the air mass properties to inhibit boundary layer growth and thus indirectly aggravating air pollution. This study highlights the need to further investigate the foehn and its impacts on air pollution in the BTH region.

A foehn-induced haze front in Beijing: observations and implications

Despite frequent foehns in the Beijing–Tianjin–Hebei (BTH) region, there are only a few studies of their effects on air pollution in this region, or elsewhere. Here, we discuss a foehn-induced haze front (HF) event using observational data to document its structure and evolution. Using a dense network of comprehensive measurements in the BTH region, our analyses indicate that the foehn played an important role in the formation of the HF with significant impacts on air pollution. Northerly warm–dry foehn winds, with low particulate concentration in the northern area, collided with a cold–wet polluted air mass to the south and formed an HF in the urban area. The HF, which is associated with a surface wind convergence line and distinct contrasts of temperatures, humidity and pollutant concentrations, resulted in an explosive growth of particulate concentration. As the plains-mountain wind circulation was overpowered by the foehn, a weak pressure gradient due to the different air densities between air masses was the main factor forcing advances of the polluted air mass into the clean air mass, resulting in severe air pollution over the main urban areas. Our results show that the foehn can affect air pollution through two effects: direct wind transport of air pollutants, and altering the air mass properties to inhibit boundary-layer growth and thus indirectly aggravating air pollution. This study highlights the need to further investigate the foehn and its impacts on air pollution in the BTH region.