Tracing Outdoor/Indoor Penetration of PM2.5,PM1.0 by 210Po/210Pb

Abstract

Alpha activities of 210Po were determined in low-volume, 24-hour samples of 2 particulate matter (PM) size fractions indoors and outdoors in 3 localities in the centre of Prague during the winter periods of 2002-2003. High values of ventilation rates (0.34 0.12h 1) and penetration of outdoor aerosols into the indoor environment, which favours particles smaller than 1 m size, allows the application of a simplified equation of the indoor/outdoor (I/O) relationship. The slope of linear regression of indoors against outdoors for both mass concentrations and alpha activities as well as the I/O penetration factors C_mass, and Calpha, respectively were determined. While the C_mass ranged from 0.46 to 0.64, appropriate Calpha ranged from 0.57 to 0.95 being always greater and reflecting size selective particle penetration through the building envelope. Personal activities indoors had little effect on particle deposition indoors, which is in agreement with the finding that the majority (70%) of PM_2.5 indoors is formed by PM_1.0. For all 3 localities it was shown that outdoor PM concentrations determined indoor ones while probably the particle removal during infiltration through the building envelope is the most important aerosol loss mechanism.

Keywords

Urban air Penetration coefficient Natural radioisotopes PM 2.5 PM 1.0

Get full access to this article

View all access options for this article.

References

Jones NC , Thornton CA , Mark D , Harrison RM : Indoor/outdoor relationships of particulate matter in domestic homes with roadside, urban and rural locations . Atmos Environ 2000;34: 2603-2612 .

Morawska L , He C , Hitchins J , Gilbert D , Parappukkaran S : The relationship between indoor and outdoor airborne particles in the residential environment . Atmos Environ 2001;35: 3463-3473 .

Chao CYH , Tung TC : An empirical model for outdoor contaminant transmission into residential buildings and experimental verification . Atmos Environ 2001;35: 1585-1596 .

Mosley RB , Greenwell DJ , Sparks LE , Guo Z , Tucker WG , Fortmann R , Whitfield C : Penetration of ambient fine particles into the indoor environment . Aerosol Sci Technol 2001;34: 127-136 .

Ní Riain CM , Mark D , Davies M , Harrison RM , Byrne MA : Averaging periods for indoor-outdoor ratios of pollution in naturally ventilated non-domestic buildings near a busy road . Atmos Environ 2003;37: 4121-4132 .

Marley NA , Gaffney JS , Drayton PJ , Cunnigham MM , Orlandini KJ , and Paode R : Measurement of 210Pb, 210Po, and 210Bi in size-fractionated atmospheric aerosols: an estimate of fine-aerosol residence times . Aerosol Sci Technol 2000;32: 569-583 .

Baskaran M , Shaw GE : Residence time of arctic haze aerosols using the concentrations and activity ratios of 210Po, 210Pb, and 7Be . J Aerosol Sci 2001;32: 443-452 .

Harley NH , Chittaporn P , Fisenne IM , Perry P : 222Rn decay products as tracer of indoor and outdoor aerosol particle size . J Environmental Radioactivity 2000;51: 27-35 .

Ramachandran G , Adgate JL , Pratt GC , Sexton K : Characterizing indoor and outdoor 15 minute average PM2.5 concentrations in urban neighborhoods . Aerosol Sci Technol 2003;37: 33-45 .