Wind prefiltering and Indoor Air Quality in the vernacular architecture ofhot arid regions of Iran.

The results of a recent research and it'sstatistical analysis, show that in some of theIranian cities like YAZD, there are two periods(from end of august to end of September andfrom end of February to end of March) in whichoutdoor pollution is higher than other periods.School starting and industrial activities in thesummer could be the prime reasons of thisphenomenon. Also dry land due to hightemperature and less humidity make summer bethe most contaminated period (Naddafi, 2006).The above problems are increased afterindustrialization of the city by construction ofthe new and modern buildings instead of theancient way of architecture in some quarters ofthe city.It's clear that more attention should be paid toincrease the quality of indoor air and the threestrategies for reducing pollutants-which aresource control, ventilation, and air cleaning-(inorder of effectiveness) should be respected.While obvious solution to such problems is toinstall a mechanical air filtration system, that isnot always practical. In particular, the characterod some historical houses and somearchaeological sites would be degraded bypresence of mechanical air distribution system.This paper presents some rules of design inthe vernacular urban design and traditionalhouses to better understand how to avoidentrance of sands, dusts and large particles intothe indoor environment.Of course the ancient strategies of airsupplyingare not completely and enough efficient to filter particles; but help us to examine possibility of using some simple design criteria to have passive pre filtration of the wind (which is the first source of natural ventilation in the hot arid vernaculararchitecture).