Multiple Chemical Sensitivity Etiology
Airway Genetics and Ambient Combustion Aerosol
Mgt 104 Respirators: Particles and Adsorbed Hydrocarbons
Also see Mgt 104a Carbon in Respirators.
Moldex 2300 and 3M 8511 disposable NIOSH N95 particulate respirators with exhalation valves are available from Airgas.com and Grainger.com possibly less contaminated than if purchased from a retail environment. Airgas.com price was lower but with a minimum order requirement. 3M 8511 are also sold as sanding respirators at Home Depot.
The 3M 8511 has a glue-like odor and is prone to clogging with moisture during damp conditions.
The Moldex 2300N95 has a thinner construction with an interior layer having an almost moist or sticky aspect - which may result in less exposure to accumulated particles compared to the thicker material of the 3M 8511. The Moldex may also filter more effectively, does much better concerning dampness, holds its shape, and may be a better choice. The Moldex valve may curl and leak after extended use. However, by that time it is usually overdue to be replaced.
The Moldex requires wiring clips to the mesh because they come without nose clips. The customization is done as with the 8511 - the wire obtained from supermarket produce twist ties by separating from the paper material.
The 8511 required wiring on additional stiffer clips and removing the nose cushion to tighten the fit. I also replaced the straps with nylon velvet trim - connected to round elastic (through hole in trim - knot at end to hold in place) - to easy on off velcro attachment behind the head and neck - with cordlock adjustment where the elastic goes through the velcro. Similar 3M models such as the 8211 differ in having a black rubber face seal and did not perform well. The soft rubber reduces pressure and tightness against the face allowing leakage.
One moment with the Moldex 2300N95 or 3M 8511 taken off brings more extended, intense hangover than all day with the respirator on. This would seem to indicate that the respirator is providing far greater efficiency than 95% - perhaps more than 99% effective in blocking MCS provoking chemical in the airway.
The respirator is rated 95% efficient with .3 micron NACL aerosol - much of exposure consisting of adsorbed hydrocarbons on particle cores or agglomerates approx .3 micron in size (SOCIETY OF AUTOMOTIVE ENGINEERS. SCHEMATIC OF DIESEL PARTICLES AND VAPOR PHASE COMPOUNDS. SAE PAPER NO. 940233 1994).
Woodburning and charbroiling peak at .1 to .2 and cigarettes between .3 and .4 micron diameter (KLEEMAN ET AL. SIZE AND COMPOSITION DISTRIBUTION OF FINE PARTICULATE MATTER EMITTED FROM WOOD BURNING, MEAT CHARBROILING, AND CIGARETTES. ENVIRON SCI TECHNOL 33(20): 3516-3523). These sizes are also near the rated efficiency of the respirator.
Larger particles from combustion - such as woodburning, charbroiling, cigarettes, and diesel just mentioned - in the .5 to 10 micron range may be nearly 100% removed by the respirator.
The denser adsorbed chemical on the particles is in larger quantity than that in the gas phase and have a longer residence time in tissue than gases.
A possible advantage of the disposable PM respirator over a PM filter cartridge mask is the ability to pinch the nose closed with the clips. Much of the reactive sensory nerves are in the nasal airway - being able to prevent direct flow may be helpful.
Though reducing symptoms and intensity - there are still effects while wearing the respirator.
Disposable respirators without exhalation valve are more difficult for breathing - unimpeded exhalation powers the reflex for inhalation - and those printed are contaminated with fine particles of the print material.
If anyone is using a respirator that is more practical and effective than the Moldex just described - please let me know.
From Wikipedia concerning how PM respirators work:
"...by particles which are following a line of flow in the airstream coming within one radius of a fiber and adhering to it, called interception;
- by larger particles unable to follow the curving contours of the airstream being forced to embed in one of the fibers directly, called impaction; this increases with diminishing fiber separation and higher air flow velocity
- by an enhancing mechanism called diffusion, which is a result of the collision with gas molecules by the smallest particles, especially those below 100 nm in diameter, which are thereby impeded and delayed in their path through the filter; this effect is similar to Brownian motion and increases the probability that particles will be stopped by either of the two mechanisms above; it becomes dominant at lower air flow velocities
- by using certain resins, waxes, and plastics as coatings on the filter material to attract particles with an electrostatic charge that holds them on the surface of the filter material;
- by using gravity and allowing particles to settle into the filter material (this effect is typically negligible); and
- by using the particles themselves, after the filter has been used, to act as a filter medium for other particles.
Considering only particulates carried on an air stream and a fiber mesh filter, diffusion predominates below the 0.1 μm diameter particle size. Impaction and interception predominate above 0.4 μm. In between, near the 0.3 μm most penetrating particle size (MPPS), diffusion and interception predominate.
For maximum efficiency of particle removal and to decrease resistance to airflow through the filter, particulate filters are designed to keep the velocity of air passing through the filter medium as low as possible. This is achieved by manipulating the slope and shape of the filter to provide larger surface area..."
Mgt 104a Carbon in Respirators
References
Kleeman M.J. et al. Size and composition distribution of fine particle matter emitted from woodburning, meat charbroiling, and cigarettes. Env Sc Tech 33;20: 3516-23 1999
Society of Automotive Engineers. Schematic of diesel particles and vapor phase compounds. SAE Paper no. 940233 1994
Views: 307
About
© 2024 Created by michael edward badolato jr.
Powered by
