Pollutants of outdoor air

Pollutants produced outdoors may penetrate into the indoor environment and may affect human health by exposure both indoors and outdoors. This is why it is important to control the air intake into a building. Also the use of openable windows needs to be considered in most polluted areas.

• Various chemicals are emitted into the outdoor air from both natural and man-made sources. The increase in air pollution is result of expanding use of fossil energy sources and the growth in the manufacture and use of chemicals. However concentrations of e.g. sulfur dioxide and nitrogen oxides emission are already declining in Europe today, the pollutants of most concern for human health are airborne particulates and ozone – indeed no safe levels have yet been identified for either.
    
• The subject of the long-range transport of air pollution expands the problem of fine (PM2,5) particulates over national frontiers and from city centres to rural districts. Recent studies suggest that short-term variations in particulate matter exposure are associated with health effects even at low levels of exposure (below 100 µg/m3). The range of health effects is broad, but are mainly to the respiratory and cardiovascular systems. All population is affected, but susceptibility to the pollution may vary with health or age. Loss of statistical life expectancy in the Europe is from 1 to over 10 years with existing fine particulate level. Outdoor air particulates including fine particulates can be reduced using high-efficiency fine filters (F7 or F8) in air handling units (AHU) and replacing filters regularly, minimum 2 times per year.
    
• Ozone in the stratosphere is valuable as it protects us from harmful ultraviolet radiation, but ozone near ground level is harmful to ecosystems and human health. Ground-level ozone is formed in the atmosphere by reaction between volatile organic compounds (VOC) and NOX in the presence of sunlight. There is a great deal of evidence to show that high concentrations of ozone can harm lung function and irritate the respiratory system. However ozone can be used for killing micro organisms in air and water sources,as long as there is a safety system in place to prevent ozone to get into the occupied spaces.
     
• In areas where there are high radon levels in rock mantle, the base floor design and implementation is critical.
    

At the same time we have to take care of how the building effects its environment. It is important that the quality of exhaust air from building is clean enough. A special attention needs to be paid in densely populated areas.