**4. Conclusion**

PAH concentrations were variable through the study due to environmental conditions of season, wet (rain) and dry (dust) deposition mainly for crops and soil. The quality of atmospheric conditions defines the contamination in these zones, both for wet and dry deposition. For the case of crops (apple and cactus stem) the values were high over the skins for high and intermediate molecular weights, but values declines with adequate washing or peeling. In soils the values found were within permissible limits of individual PAHs such as benzo(a)pyrene. Organic matter has a high affinity to catch organic contaminants in soils; it is a crucial environmental parameter that regulates the availability of inorganic and organic contaminants in the environment.

This type of study is important to evaluate the degree of contamination in specific environments, considering environmental variables to know the movement the organic contaminants. This will also help guarantee the quality of food produced in semi rural zones nearest to high density population and/or industrial areas such as Mexico City.

Nowadays, the new technologies employ in fuels, gasoline and diesel engines and programs of industrial-vehicular control has improvement the air quality in Mexico City. These actions have the goal to reduce many organic contaminants in favour of human and environment health. In the last years.
