Stochastic analysis of concentration field in a wake region.
BACKGROUND
Identifying geographic locations in urban areas from which air pollutants enter the atmosphere is one of the most important information needed to develop effective mitigation strategies for pollution control.


METHODS
Stochastic analysis is a powerful tool that can be used for estimating concentration fluctuation in plume dispersion in a wake region around buildings. Only few studies have been devoted to evaluate applications of stochastic analysis to pollutant dispersion in an urban area. This study was designed to investigate the concentration fields in the wake region using obstacle model such as an isolated building model. We measured concentration fluctuations at centerline of various downwind distances from the source, and different heights with the frequency of 1 KHz. Concentration fields were analyzed stochastically, using the probability density functions (pdf). Stochastic analysis was performed on the concentration fluctuation and the pdf of mean concentration, fluctuation intensity, and crosswind mean-plume dispersion.


RESULTS
The pdf of the concentration fluctuation data have shown a significant non-Gaussian behavior. The lognormal distribution appeared to be the best fit to the shape of concentration measured in the boundary layer. We observed that the plume dispersion pdf near the source was shorter than the plume dispersion far from the source.


CONCLUSIONS
Our findings suggest that the use of stochastic technique in complex building environment can be a powerful tool to help understand the distribution and location of air pollutants.
Yassin
Mohamed F
MF
Department of Environmental Technology Management, College for Women, Kuwait University, P.O. Box 5969, Kuwait, Safat 13060, State of Kuwait. mohamed_f_yassin@hotmail.com
Elmi
Abdirashid A
AA
D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000517:prevention & control; D002947:Cities; D005030:Ethylenes / Q000032:analysis; D005410:Flame Ionization; D007202:Indicators and Reagents / Q000032:analysis; D008956:Models, Chemical; D011336:Probability; D013269:Stochastic Processes; D014919:Wind
D000393:Air Pollutants; D005030:Ethylenes; D007202:Indicators and Reagents; C036216:ethylene