Module 17: Air Cleaners for Nanoparticles
Channel: METPHAST Program
Date: 2017-01-25

The objectives for this module are that, by the end, learners should be able to (1) list the main technologies used to remove particles from moving air, (2) identify air cleaning technologies that are effective for nanoparticles, (3) describe the mechanisms by which fibrous air filters capture particles, and (4) explain why fibrous air filters can capture nanoparticles with high efficiency.

Table of Contents: 

00:00 - Slide 1
00:05 - Air Cleaners for Nanoparticles
00:17 - Slide 3
00:41 - Factors that Influence Air Cleaner Selection
01:59 - Important Parameters
03:10 - Particle Collectors
03:33 - Settling Chambers
04:27 - Inertial Collectors
06:00 - Cyclones
07:32 - Particle Scrubbers
09:01 - Electrostatic Precipitators (ESPs)
10:42 - Types of ESPs
11:58 - Fabric Filters
14:26 - Inside Collectors
15:02 - Outside Collectors
15:44 - Fibrous Filters
18:12 - Slide 17
18:37 - Mechanical Filtration Mechanisms
20:28 - Single-Fiber Efficiency Prediction
24:32 - Single-Fiber Efficiency
26:17 - Total Filter Efficiency
26:45 - Electrostatic Attraction Scenarios
27:44 - Electrostatic Filtration Mechanisms
28:51 - Types of "Electret" Filters
30:38 - Why use electret filters?
31:12 - Predictive Equations
32:13 - Influence of Mechanisms
33:51 - Electrostatic Effects on Respirator Filters
34:58 - ASHRAE Filter Test Standards
36:50 - MERV
37:55 - Nanoparticle Filtration Theory
38:41 - Filtration Study (w/ Methodological Errors)
39:18 - Filtration Studies (Good Ones)
41:00 - Important Points!!
41:21 - Do filters work as well as they're rated?
42:07 - Hospital HVAC Filter Performance
43:00 - Filter Performance with Use
43:41 - Test Filters
44:24 - Test Location
45:23 - Sampling
45:38 - Testing Dates
45:57 - Test Procedure
46:56 - Results: Glass vs. Synthetic Fibers
48:01 - Efficiency vs. Time, Diameter = 1.03 μm
48:40 - Pressure Drop vs. Time
49:20 - What's going on?
50:08 - Are these results generalizable?
51:02 - What about engineered nanomaterials?
51:55 - Recommendations for Control Filters
52:48 - Respirator Filter Penetration
54:39 - Respirator Penetration with Steady Loading
55:03 - Penetration with Intermittent Loading
55:41 - Respiratory Protection Key Points
56:50 - Slide 54
57:30 - Slide 55