[Stoves] personal pollution monitors (Andrew)

[IPC]

Hi, Frank
Yes, I think humidity affects charge on airborne particles, and facilitates clustering. The pressure at -2500m is around 135.8kPa, vs 101.3 at sea level.  It is necessary to derate diesel engines operated at those depths, or they are over-supercharged. Both density and viscosity effects caused by pressure affect precipitation. Gravity effects - no, too small to matter. And no, there is a significant wind in many places, because the workers need both fresh air and cooling, and ventilation air is the primary coolant (the virgin rock temperatures - i.e.rock temperatures when first exposed by mining - at 2500m can be over 80 deg C). Humans cannot work at wet bulb temperatures above 36 deg C.
Philip
   

-----Original Message-----
From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Frank Shields
Sent: Sunday, December 25, 2016 12:53 AM
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] personal pollution monitors (Andrew)

> The fraction in air was strongly dependent on humidity and somewhat dependent on pressure (some mines were 2500m below sea level). The fraction also fell with time after blast, but this process was quite slow.
Philip

Interesting!  High humidity lowers the air particle count? due to moisture making the particles heavy - stick and they fall faster?

And pressure? What is the pressure at 2500m below sea level? Never thought of that before. Higher than that at sea level? and how will that effect air particles? What about gravity? That will be higher and more pull?

I assume no wind meaning a greater chance the particles will have a chance to fall. 

Thanks

Frank











Thanks

Frank
Frank Shields
Gabilan Laboratory
Keith Day Company, Inc.
1091 Madison Lane
Salinas, CA  93907
(831) 246-0417 cell
(831) 771-0126 office
fShields at keithdaycompany.com



franke at cruzio.com



> On Dec 24, 2016, at 2:07 AM, IPC <ipcipc at mweb.co.za> wrote:
> 
> At the Chamber of Mines we did an enormous amount of work on silica inhalation. In brief our findings were that the material of most concern was the 1.6-0.5 micron fraction, because that had significant retention in the deep-lung tissue. The fraction in air was strongly dependent on humidity and somewhat dependent on pressure (some mines were 2500m below sea level). The fraction also fell with time after blast, but this process was quite slow.
> Philip
> 
> -----Original Message-----
> From: Stoves [mailto:stoves-bounces at lists.bioenergylists.org] On 
> Behalf Of Crispin Pemberton-Pigott
> Sent: Saturday, December 24, 2016 1:17 AM
> To: Discussion of biomass cooking stoves
> Subject: Re: [Stoves] personal pollution monitors (Andrew)
> 
> "I do wonder why we have gravitated to PM2.5 when 15 years ago only pm10 seemed to be mentioned.‎"
> 
> PM 10 looks bad but isn't very harmful, on average (equitoxicity).
> 
> PM2.5 is a 'blank zone'. There is almost none around. A small measurement error such as a separator running slightly 'off' gives the same result as one 'on'. It was chosen deliberately because there isn't much to be wrong about. 
> 
> PM10 was early days stuff. There is a lot right on that size. If the sampler is a little off, there is a lot to be wrong about so calibrating and replicating are a bit challenging (to say the least).
> 
> Even a small difference in a separator's function ‎created a significant difference in the result. 
> 
> 'Breathable' in terms of inhalation starts at PM 4, not 2.5. However nearly all wood and coal and LPG and ethanol smoke is under PM1.6. The particles are very different in terms of their toxicity. Nikhil is making that point. 
> 
> Regards
> Crispin
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