particle

The risen awareness of improved indoor air quality has resulted in an increased energy demand for HVAC systems due to higher air exchange rates and the additional operation of air purifiers. Therefore, the need for energy-efficient methods to improve indoor air quality has grown. In this experimental study, we develop an innovative wet scrubber concept to remove solid particles from the airflow. In contrast to conventional wet scrubbers, this concept uses a perforated plate and the hydrostatic pressure to feed water droplets into the air stream.

Cooking activities generate massive fine particulate matter (number concentration). Effective ventilation system can improve the indoor air quality impacts of pollutants from residential cooking. Make-up air supply system can improve the range hood and Indoor air quality. In this study, we measured a capture efficiency of range hood with make-up air supply and indoor particles during cooking activates. For household’s comfort, make-up air supply was installed the line diffuser type. Case 1 PN concentrations increased to around 60,000#/cm3.

Scientific studies have linked particulate matter with a series of significant health problems. In ventilation systems, indoor particle concentration and dust load on air duct surfaces are two concerns for human health. PROBE-PM (Predicting code for building environment-particulate matter transport simulation), a code to simulate the particle transport in the whole ventilation system is developed.

This study developed a drift-flux model for particle movements in turbulent indoor airflows. To account for the process of particle deposition at solid boundaries in the numerical model, a semi-empirical deposition model was adopted in which the sizedependent deposition characteristics were well resolved. After validation against the experimental data, the drift-flux model was used to investigate human exposures to particles in three normally-used ventilation types: mixing ventilation (MV), displacement ventilation (DV), and under-floor air distribution (UFAD).

LBNL - Proceedings of Indoor Air 2002 (9th International Conference on Indoor Air Quality and Climate) - June 30 - July 5, 2002 - Monterey, California - vol 1, pp 521-526, 3 figs, 10 refs","This paper presents a model for particle deposition on fin-and-tube heat exchangers, that takes into account mechanisms such as impaction, diffusion, gravitational settling and turbulence. Models results are presented and analysed. They agree with experimental data.

This report is concerned with the strategy and methodology for investigating four major categories of biological particles in the indoor air of private houses, non-industrial workplaces and public buildings (excluding hospitals). These particles are mites and their faeces; dander from pets and other furred animals; fungi, including moulds and yeasts; and bacteria, including actinomycetes.

The concentrations of ozone, particles (PM10 and PM2.5) and ultra-fine particles were measured duringdriving the automobile and during standing. Two ventilation modes were prepared; 1) all fresh air modeand 2) all re-circulation mode. The windows of the automobile had been always closed during thismeasurement. The indoor/outdoor ratio of the concentrations and the correlation among thosesubstances were reported. The concentrations of particles (PM10 and PM2.5) and ultra-fine particleswere dramatically had been increased while the automobile followed the trailer bus.

Use of a portable HEPA filter cleaner in a room is believed to be capable of reducing the risk oftransmission of infectious diseases through removing the particles or large droplets to which pathogensare attached. It is hoped that the portable HEPA filter(s) can increase the effective air change rate (forparticle removal only) in a general ward to the ventilation standard of an isolation ward for emerginginfection diseases when there are insufficient number of isolation wards.

The fine filter (EU7) was included in the ventilation system which operated at full capacity only during working days. The first three months the filter was located in the ventilation system of the office building and it was later moved for one month period into the laboratory chamber. The aim of the study was to investigate whether particles or microbes are released from the filter during the turn off and start up of the fan. The released particle (size range of 0.3 m) concentration was below 10 #/dm 3 in normal field conditions.

Values for total dust concentration in indoor air in day-care centres, offices and schools with no reported problems are measured. These are: day-care centres 41 14 g/m3, offices 16 5 g/m3, schools 20 10 g/m3. In parallel the particle size distribution in six interval from 0.3 m - >20 m are reported. No seasonal variation in total dust concentration could be seen. Sudden increase in number of the particles in the smallest intervals are found at night for some systems when they are shut down or working on reduced speed.