outdoor air

We studied the effect of ventilation and air filtration systems on indoor air quality in a children's day-care center in Finland. Ambient air nitrogen oxides (NO, N02) and particles (TSP, PM10) were simultaneously measured outdoors and indoors with automatic nitrogen oxide analyzers and dust monitoring. Without filtration nitrogen oxides and particulate matter generated by nearby motor traffic penetrated readily indoors. With chemical filtration 50-70% of nitrogen oxides could be removed. Mechanical ventilation and filtration also reduced indoor particle levels.

Knowledge and estimation of the wind speed and air flow characteristics, in a city, is of vitalimportance for passive cooling applications and especially in the design of naturallyventilated buildings. This study is referred to the analysis of the wind characteristics in urbancanyons as a function of the free stream wind. The impact on the airflow rate calculation isdiscussed for an urban canyon. The goal of this study is to get a better insight of the impact ofthe urban environment on the ventilation effectiveness.

Natural ventilation is one of the most fundamental techniques to reduce energy usage inbuildings. However, due to complicated site plans and building layouts, it is difficult todesign optimal layouts for the enhancement of ventilation without knowledge about the flowpatterns. The employment of computational fluid dynamic (CFD) tools in the design processcan give predictive feedback to the designers, allowing them to optimize airflow around thesite to decide on building placement, orientation, and interior space layout.

The traditional way to dehumidify the outdoor air in an A/C-system is by cooling the air downbelow the dew point temperature. For this process a refrigeration system is necessary torealise these low temperatures. Nowadays the disadvantages of refrigeration systems fordehumidification are widely known. An alternative method to dehumidify the air is byseparating the process of dehumidification and cooling.The paper will present a testing plant of 1200 m air/h which is installed in the University ofEssen. This A/C-systems works with liquid desiccants.

A park influences its surroundings. Temperature inside and around the park varies in a special way. Air quality also varies. And the park creates its own wind system.          

Breathing walls were installed on opposite sides of a scale mock-up model of a housing structure that was situated in an artificial climate test room. We analyzed the thermal insulation capability. heat recovery effect and indoor climate for the inflow of outdoor air across the breathing wall. The rate of heat recovery reached 30% under strong winds of up to 8 mis. Even when the ventilation rate tripled due to the strong wind, the temperature difference in the vertical direction was less than 2 K.

This publication is intended to provide guidance on the nature and characteristics of pollutants in the outdoor air and how this impacts on indoor air quality. In particular, the document summarises the available knowledge to provide designers with information that will help in locating their ventilation inlets to minimise cross contamination from a range of polluting sources.                   

Gives a brief account of some of the parameters that are important in understanding the interactions of the external environment with the indoor environment, in order to enable the development of low energy ventilation solutions for buildings in urban locations with regard to indoor air quality and thermal comfort. Also describes work that is being carried out at the Building Research Establishment Ltd (BRE) in the UK to address them.