Air and Climate Change Research
Indoor Air Toxics Chamber Tests
Both Small and Large Chambers
As a result of recent studies indicating significant correlations of increased mortality and morbidity with increases in ambient fine particles, it has become even more important that we better understand personal exposures to fine particles indoors. Most people spend most of their time indoors, and the ones at greatest risk in the studies mentioned above spend nearly all their time indoors.
One of the major thrusts of APPCD's fine-particle research efforts is to determine the contribution to personal indoor exposure of fine particles that originate outdoors. The Division's two-compartment research facility is used to study the mechanisms by which fine particles in the outdoors penetrate into the indoor environment.
The facility consists of two, nearly identical, room-sized (30 m3) compartments. The compartments are separated by a partition in which simulated air entry paths can be mounted. The partition has an open surface area of 9 m2. This facility is used to verify mathematical models for penetration of fine particles through well-defined entry paths. In the future, it will be used to measure particle penetration through openings created by installation of commercially available building components such as windows and doors.
Statement of Work
The facility consists of two, nearly identical, room-sized (30 m3) compartments. The compartments are separated by a partition in which simulated air entry paths can be mounted. The partition’ has an open surface area of 9 m2. This facility is used to verify mathematical models for penetration of fine particles through well-defined entry paths. In the future, it will be used to measure particle penetration through openings created by installation of commercially available building components such as windows and doors.
Design Specifications for Two Compartment Chamber –TCC (aka the Replacement Indoor/Outdoor Research Chamber)
The new Indoor/Outdoor Research Chamber design consists of two adjoined compartments, an air distribution system, contaminantsampling and generation systems, and a process control and monitoring system. Planned areas of study include:
- relationship between indoor pollutants (gaseous and particulate) and their outdoor counterparts.
- relationship of indoor and outdoor combustion related products.
- interactions between indoor and outdoor environmental conditions.
- contaminant transport through building envelopes.
The chamber contains two identically sized compartments with interior dimensions of 10’ depth by 12’ width by 8’ height. Materials used throughout are non-emitting and non-shedding (stainless steel, Teflon, etc.). The chamber system is seamless stainless steel, polished to No. 4 grade or better. The exterior walls are insulated, double wall construction 4 to 6 inches thick. The chamber has leak tight penetrations to accommodate entry, electrical power, environmental sensors, and instrument sampling and media injection. Extra penetrations for future use are included. A removable partition separates the two compartments. Various leak paths are installed into the partition for testing. The acceptable leak rate for the chamber system, when assembled, is less than 0.1% of the circulation rate.
The air distribution system provides clean, conditioned air to the chamber through multiple flow modes. Ultra Low Particle (ULPA) and High Efficiency Particle (HEPA) filtration, carbon beds and UV lamps are used to filter out particles, organic and inorganic compounds, and bio-aerosols from the gas stream. An inline heating/cooling/humidity unit adjusts and controls the temperature and humidity of the gas stream. The chamber is designed to operate in single-pass and circulation modes with or without cleaned and conditioned make-up air. Airflow is monitored through orifice plates and controlled by variable flow rate blowers. Operating environmental conditions are monitored by typical instrumentation; differential pressure transmitters, RTD temperature and humidity probes, etc.
The chamber design incorporates numerous sampling ports for particles or gases throughout the chamber system. Groups of two or more tube penetrations are spaced on all outer walls at multiple horizontal and vertical locations. Tubes are ¼” and ½” stainless steel in diameter and extend into the compartments to varying depths. Sampling ports are designed for various locations within the air control ducting. These locations allow performance monitoring of the system components and monitoring the exhaust gas stream to the atmosphere. Numerous particle and gas injection (generation) ports are designed for the chamber walls and the inlet gas stream.
A central monitoring and process control station is planned to automate the operation of the chamber system. Background contamination requirements for the chamber are:
- Particles: <100 particles/m3(approximate instrument minimum detection limit)
- Total organic compounds: <1mg/m3
- Individual organic compound: <0.2mg/m3
- Inorganic compounds: <1mg/m3(O3, NOx, SOx, etc.)
- Inorganic compounds: <1mg/m3(O3, NOx, SOx, etc.)
- Bio-aerosols: undetermined at this point
- Temperature: 15 to 35 oC, +/-0.5 oC
- Humidity: 30 to 80 % RH, +/-5 % RH
- Differential pressure between chamber compartments: 0 to 20 Pascal, +/-0.1 %
- Air exchange rate of chamber: 0.03 to 2.5 ACh-1
- Flow rate range expected to produce desired air exchange rates is 0.5 to 40 cfm.
- Total system leak rate: <0.1 % of total circulation flow rate.
Instruments available for sampling and generation include:
- TSI, Aerosol Particle Sizer, Model 3320
- TSI, Aerosol Diluter, Model 3302
- TSI, Impactor Inlet, Model 3306<
- TSI, Scanning Mobility Particle Sizer, Model 3934
- PMS, Laser Aerosol Spectrometer, Model LAS-X CRT
- Dekati, Electrical Low Pressure Impactor
- Climet, Spectro .3
- Climet, CI-500
- Grimm, Portable Dust Monitor, Model 1.104
- TSI, Condensation Monodisperse Particle Generator, Model 3475
- TSI, Constant Output Atomizer, Model 3075/6
- TSI, Aerosol Atomizer, Model 9302
- TSI, Fluidized Bed Aerosol Generator, Model 3400
- Dust Generator (In house)
- LAT, Automatic Tracer Gas Monitor, Model 101
- Pylon, Portable Radiation Monitor, Model AB-5
- Genitron, AlphaGuard Portable Radiation Monitor