First results on transient plasma-based remediation of nanoscale particulate matter in restaurant smoke emissions

Lessons from the history of inorganic nanoparticles for inhalable diagnostics and therapeutics

The respiratory tract is one of the most accessible ones to exogenous nanoparticles, yet drug delivery by their means to it is made extraordinarily challenging because of the plexus of aerodynamic, hemodynamic and biomolecular factors at cellular and extracellular levels that synergistically define the safety and efficacy of this process. Here, the use of inorganic nanoparticles (INPs) for inhalable diagnostics and therapies of the lung is viewed through the prism of the history of studies on the interaction of INPs with the lower respiratory tract. The most conceptually and methodologically innovative and illuminative studies are referred to in the chronological order, as they were reported in the literature, and the trends in the progress of understanding this interaction of immense therapeutic and toxicological significance are being deduced from it. The most outstanding actual trends delineated include the diminishment of toxicity via surface functionalization, cell targeting, tagging and tracking via controlled binding and uptake, hybrid INP treatments, magnetic guidance, combined drug and gene delivery, use as adjuvants in inhalable vaccines, and other. Many of the understudied research directions, which have been accomplished by the nanostructured organic polymers in the pulmonary niche, are discussed. The progress in the use of INPs as inhalable diagnostics or therapeutics has been hampered by their well-recognized inflammatory potential and toxicity in the respiratory tract. However, the annual numbers of methodologically innovative studies have been on the rise throughout the past two decades, suggesting that this is a prolific direction of research, its comparatively poor commercial takings notwithstanding. Still, the lack of consensus on the effects of many INP compositions at low but therapeutically effective doses, the plethora of contradictory reports on ostensibly identical chemical compositions and NP properties, and the many cases of antagonism in combinatorial NP treatments imply that the rational design of inhalable medical devices based on INPs must rely on qualitative principles for the most part and embrace a partially stochastic approach as well. At the same time, the fact that the most studied INPs for pulmonary applications have been those with some of the thickest records of pulmonary toxicity, e.g., carbon, silver, gold, silica and iron oxide, is a silent call for the expansion of the search for new inorganic compositions for use in inhalable therapies to new territories.

Exposure characteristics and risk assessment of air particles in a Chinese hotel kitchen

Background

The hazards of kitchen particles have attracted social attention, but their distribution characteristics and risk assessment are rarely reported.

Objective

To explore the temporal and spatial distribution characteristics of kitchen particles, analyze the variations in characteristics of number concentration (NC), mass concentration (MC), surface area concentration (SAC), and particle size distribution, provide reference indexes for evaluating worker exposure, evaluate the risk of kitchen particles, as well as suggest improvements and control measures.

Patients and methods

Different cooking posts in a Chinese hotel kitchen were selected to monitor exposure to particles, explore the temporal and spatial distribution characteristics of NC, MC, and SAC of particles in the cooking post, analyze changes in the particle size, compare the individual exposure of particles between the cooking and steaming posts, and analyze the correlation between NC, MC, and SAC. Risk assessment of kitchen ultrafine particles was performed using a Nanotool.

Results

The sizes and fluctuation ranges of NC_{10 - 500nm} at cooking posts during lunch preparation and at peak periods were significantly higher than those at the end of the lunch period. The mean values of MC_{10 - 500nm} during the lunch preparation peak and ending periods were 0.149, 0.229, and 0.151 mg m^-3, respectively. The mean values of SAC_{10 - 500nm} were 225, 961, and 466 μm²·cm^-3, respectively. The mode diameter of exposed particles at the cooking post [(34.98 ± 2.33) nm] was higher than that at the steaming post [(30.11 ± 2.17) nm] (P < 0.01). The correlation between SAC_{10 - 500nm} and NC_{10 - 500nm} (r = 0.703) was the strongest. Nanotool gave a hazard rating ratio, exposure rating ratio, and risk ratio of 0.75.

Conclusion

The sizes of the NC, MC, and SAC of the particles at the cooking post were related to the kitchen operations. Since kitchen particles are of high exposure and risk levels, protective measures should be formulated and implemented to deal with them safely.

Effect of upflow and downflow baffle configuration on particulate matter removal in a mirror-symmetrical multi-compartment scrubber

Control over particulate matter (PM) emission from grilling is required for improving public health and air quality. The performance of mirror-symmetrical multi-compartment scrubbers with an upflow (U-type) and downflow baffle (D-type) configuration was evaluated for PM emission control from grilling at a flow rate of 30 m³ min^-1. The PM removal efficiency of the U-type scrubber was the highest when the water level was 8 cm (95.6%), and the pressure drops recorded at the water levels of 6, 8 and 10 cm were 103, 122 and 153 mmH₂O, respectively. Although PM removal efficiency of the D-type scrubber was over 91.0% at the water levels of 8, 10 and 12 cm, the pressure drops were 124, 142 and 185 mmH₂O, respectively. A comprehensive evaluation of the water volume, pressure drop and PM removal performance, as well as device size, revealed that the U-type scrubber with a PM removal efficiency of 92% or higher and a pressure drop of 122 mmH₂O or lower at the water levels of 6-8 cm was more economical for removing PM from grilling gas than the D-type scrubber.