Respiratory Protection PPE to Safeguard against Engineered Nanoparticles
At present the field of nanotechnology is undergoing a notable change in research and development of material science. Most efforts for the research are focused on different applications; implications (i.e., its effects on health and environment) research has been behind. The overall success of nanotechnology requires assurances that all products which are developed are safe from the perspective of environment, health and safety (EHS). For this reason, earlier it was reported in pulmonary toxicity studies that lung exposures to ultrafine or nanoparticles (herein defined as particle<100 nm in a single dimension) can produce enhanced adverse inflammatory responses when comparing to large particles of alike composition.
Surface properties (typically surface area particles) and free radical generation that can result from particle interactions with cells would play vital roles in the toxicity of nanoparticles. The brief review would identify many aspects to study hazard effects and EHS risks to nanoparticle exposure. Environmental and health risk evaluations would be products of exposure and hazard assessments.
The key factors meant for discussion and selection of surgical mask would herein include importance of particle characterization studies; developing risk assessment framework for nanomaterial; as well as corresponding ‘hypothesis-driven, mechanistically-oriented investigations, attendant with base set hazard studies that can clearly demonstrate particle size would be the only factor affecting safety from nanomaterials.
Respirator Key Performance Investigation
The article discusses about the recent updates in nanoparticle safety technology and explains the science behind recommendations of NIOSH for selection and use of respiratory mask against engineered nanoparticles.
Even with decades of research by NIOSH for assuring predictable exposure reduction levels, engineered nanoparticles would easily be able to present new challenges. For example, current NIOSH certification filtration performance test (for determining whether a respirator mask is at least 95.99, or 99.97% effective) require wide range of particles, like significant nanoparticles, but only checks particles that are greater than 100nm and penetrate through the filter. In general, due to the challenges in measuring and generating nanoparticles, only a little research has been done for assessing leakage and filter penetration around the respirator face seal area.
In the year 2005, a laboratory research program was conducted by NIOSH to get a better understanding on performance of N95 mask for protection against nanoparticles. Being a vital part of the project, NIOSH researchers constructed test systems for generating aerosol challenges that are as small as 4 nanometers for determining filtration properties of EU marked and NIOSH certified respirators and non-certified dusk masks too.
All these experiments got conducted under aggressive conditions like charged neutralized particles and higher flow rates for assessment of worst-case situations. Shaffer and Rengasamy reviewed most of these works in 2009. According to a subsequent study, all these respirators got donned on manikin and other controlled sized leaks got created in respirator face seal for accessing whether nanoparticles preferentially got leaked when compared to larger particles.
Other significant Stories Behind Respiratory Objects
During a subsequent story, all respirators were donned on manikin and other sized controlled leaks got created in the dust mask face for sealing and accessing whether nanoparticles were preferentially leaked when comparing to larger particles. According to many studies it was found:
- As forecasted by single fiber filtration theory, 4 to 20 nanometer particles got captured effectively through respirator filter media, as most particles constantly got bombarded through air molecules, due to which these are deviated from airstream and come in contact with filter fiber to become trapped through filter;
- Most penetrating particle size (MPPS) range (shown in Figure 1) for electret filter media (most common filter required for using respirators in market) was between 30 to 100 nanometers, with 100-class dusk mask online having higher laboratory filtration performance when compared to N95 mask price and performance.
The most important aspect of respirators was the leak size affecting the number of nanoparticles within the respirator face-piece worn on manikin, although for the small leaks nanoparticles were more likely to found within the face-piece of disposable mask and N95-class filtering respirators.