The main goal of this research is to contribute to the best understanding of the determining factors of the dirtiness in the Porto-Novo city. The probabilist method and the random choice technique are adopted for the selection of the sample proportionally to the size or the height of the structures based on some numbers of criteria. The size of the sample is determined with Schwartz method. To identify the determining factors of the dirtiness, parameters have been set in the software mini tab 14 to realise the analysis of the simple regression. Durbin-Watson statistic testing's with, Ryan Joyner normality, and with Henry adjustment have been used to evaluate the meaningfulness of the model.
The study of the clean spaces evaluation is realised through some factors like networked evacuation of rainwater, flood and the rate of cover of the of the pre-collect in order to determine a salubriousness map. The combination of the factors of space salubriousness is realised.
So for that fact the clue or the rating of the dirtiness has been calculated taking in account the effects of the "anthropic" factors (rainwater evacuation network, pre-collect cover rate, waste bulk) on the salubriousness. It emerges the regression analysis that the increase in the subscription cost by the pre-collect structures, the empty space availability in the quarters, the overflowing of the gathering places by the DSM in the agglomeration, existence of floodable areas, the realisation of some sacrifices during religions rituals make increase the rate of dirtiness in the quarters of the study field. Moreover the DSM pre collect frequency increase in the households, brings the diminution of the rate of dirtiness in the quarters whereas, the subscription cost increase by the pre-collecte structures reduces the subscription rate and makes the houses dump some products in the empty spaces available in their areas or the refer to some gathering points (places) that are badly maintained or rarely emptied.