This project covered 16 aircrafts including both smoking and non-smoking flights from June 1996 to August 1997. The parameters concerned were carbon dioxide (C02), humidity, temperature, carbon monoxide (CO), ozone (03), bacteria, fungus, and respirable suspended particulate (RSP). Compared with the Federal Aviation Administration (FAA) standard, C02, CO and ozone levels on all flights were within such standards. Peak levels of C02 and particulate were observed during both boarding and deboarding periods.
This paper summarizes baseline results from the U.S. Environmental Protection Agency's (EPA) school demonstration studies. Indoor pollutants of concern were formaldehyde, sum of targeted volatile organic compounds o:VOC), carbon monoxide (CO), particulate matter less than 2.5 microns (PM2.5), particulate matter less than 10 microns (PM10), and bioaerosols (bacteria, fungi, and thermophiles). The five schools presented here had no significant indoor air quality problems. Locations of these schools were distributed throughout various climate zones in the United States.
The numerical investigation of airflow and chemical transport characteristics for a general class of buildings involves identifying values for model parameters, such as effective leakage areas and temperatures, for which a fair amount of uncertainty exists. A Monte Carlo simulation, with parameter values drawn from likely distributions using Latin Hypercube sampling, helps to account for these uncertainties by generating a corresponding distribution of simulated results.
This paper is based on a dual approach (experimental and numerical) in order to predict the indoor air quality for small ventilated enclosures. The experimental part employs a ventilated test room and a tracer gas technique (constant method as gas injection) to estimate the diffusion of a pollutant. The gas used is the sulphur hexafluoride (F6S). The numerical approach is a CFD simulation, adding a convection - diffusion equation (to determine the local mass fraction of the pollutant) to the equations normally used to solve a turbulent flow.
Measurement campaign was conducted in a controlled office environment during January 1999 to get indoor/outdoor ratio for particles less than 0.5 micrometers in diameter. Aerosol concentrations for diameters between 7-500 nanometers were measured simultaneously indoors and outdoors with two DMPS systems. Other continuously measured quantities included temperature, ventilation rate, relative humidity, air pressure and four inorganic gases (S02, NO, NOx and 03). The measured room was practically airtight and had a mechanical ventilation system.
Gas cooking in the home can release high levels of nitrogen dioxide (N02) and carbon monoxide (CO). This study investigated the effect of various ventilation strategies to reduce personal exposure to these pollutants. It considered the effectiveness of windows, a kitchen extract fan and trickle ventilators for different dwellings, occupant behaviour, environmental conditions etc. Strategy selection was based on the need to minimise both personal exposure and energy loss. These strategies were simulated using BRE's BREEZE multi-zonal computer code.
Symmetry is not a sufficient condition for the design of a ventilated room to generate two-dimensional airflow. Three-dimensional effects were observed in a symmetrically designed 3m x 5m x 8.5m test mom having a 0.019m slot inlet opening height under the ceiling in the one end wall. The ceiling jet velocity profile measured in the symmetric plane agreed well with the jet models for two-dimensional !low, but large differences were found out of the symmetric plane.
The flow in a ventilated room will not always be a fully developed turbulent flow. Reduced air change rates owing to energy considerations and the application of natural ventilation with openings in the outer wall will give room air movements with low turbulence effects. This paper discusses the isothermal low Reynolds number flow from a slot inlet in the end wall of the room. The experiments are made on the scale of I to 5. Measurements indicate a low Reynolds number effect in the wall jet flow.
The aim was to develop a simple dynamic model for predicting air exchange caused by short time single-sided ventilation and necessary window opening time in classrooms. Tracer gas measurements have been made in a full-scale room. The comparison indicates that the model can be used when rough estimates of air exchange are of interest.
This paper shows that under certain conditions, multiple solutions for the flow rate exist in a natural ventilation system, induced by the non-linear interaction between buoyancy and wind forces. Under certain physical simplifications, the system is governed in steady state by a non-linear algebraic equation or a system of equations. Three examples are given here: a single-zone building with two openings, a channel with two end openings, and a two-zone building with two openings in each zone. Analytical and numerical solutions are presented.
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