*3.1.3 Analysis by land use*

To assess the variability of sulfate atmospheric deposition fluxes by land use, sampling sites were grouped according to the prevailing land use as follows:

Industrial land use: Sites I, II, III, IV, V.

Urban land use: Sites VI, VII, VIII, IX, X.

According to **Figure 4**, it can be observed that mean sulfate deposition fluxes were slightly higher in sites with an urban land use; however, sites with an industrial land use showed extreme values. When Friedman tests was applied, significant differences between land use were not found. It demonstrates a spatial homogeneity that suggests the regional origin of sulfate as a result of long-range transport mainly during the rainy season.

**51**

14.05 Kg Ha<sup>−</sup><sup>1</sup>

year<sup>−</sup><sup>1</sup>

**3.2 Nitrate**

year<sup>−</sup><sup>1</sup>

*3.2.1 Seasonal variability*

was 0.78 Kg Ha<sup>−</sup><sup>1</sup>

found (**Figure 5**).

*3.2.2 Spatial variability*

flux of 1.61 Kg Ha<sup>−</sup><sup>1</sup>

Kg Ha<sup>−</sup><sup>1</sup>

**Figure 4.**

Ha<sup>−</sup><sup>1</sup>

year<sup>−</sup><sup>1</sup>

*Sulfate atmospheric deposition fluxes by land use.*

(Universidad de León) (**Figure 4**).

mean value found was 13.51 Kg Ha<sup>−</sup><sup>1</sup>

and a maximum value of 3.93 Kg Ha<sup>−</sup><sup>1</sup>

year<sup>−</sup><sup>1</sup>

with a maximum value of 2.84 Kg Ha<sup>−</sup><sup>1</sup>

season and the other two sampling seasons.

year<sup>−</sup><sup>1</sup>

minimum value of 0.22 Kg Ha<sup>−</sup><sup>1</sup>

*Mapping and Estimation of Nitrogen and Sulfur Atmospheric Deposition Fluxes…*

In the case of sites grouped with an urban land use, the mean value found was

On the other hand, in the case of sites grouped with an industrial land use, the

year<sup>−</sup><sup>1</sup>

(Instituto Tecnológico de León at SE), whereas the lowest value (1.81 Kg Ha<sup>−</sup><sup>1</sup>

was registered in site III (monitoring station IMSS-T21 at downtown of the city).

From **Figure 5**, it can be observed that the higher nitrate deposition fluxes

year<sup>−</sup><sup>1</sup>

Blanca, at SW). On the other hand, the mean value obtained for warm dry season

with a maximum of 1.47 Kg Ha<sup>−</sup><sup>1</sup>

year<sup>−</sup><sup>1</sup>

Applying Friedman tests, significant differences were found between cold dry

From the analysis by sampling site, a mean nitrate atmospheric deposition

found. The highest value was observed in site X (Loma Blanca at SW) (**Figure 6**).

with a maximum value of 3.93 Kg Ha<sup>−</sup><sup>1</sup>

Blanca at SW). Finally, during the rainy season, a mean value of 1.13 Kg Ha<sup>−</sup><sup>1</sup>

year<sup>−</sup><sup>1</sup>

were obtained during cold dry season, with a mean value of 2.93 Kg Ha<sup>−</sup><sup>1</sup>

, with a maximum and minimum values of 20.70 and 6.58

, with a maximum value of 25.82 Kg

, which corresponds to site X (Loma

in site X (Loma Blanca at SW) and a

year<sup>−</sup><sup>1</sup>

was

year<sup>−</sup><sup>1</sup>

in site V (Instituto de la Mujer at SE) were

 year<sup>−</sup><sup>1</sup> )

year<sup>−</sup><sup>1</sup>

year<sup>−</sup><sup>1</sup>

in site X (Loma

, respectively, observed in sites VI (Zoológico at NE) and site VII

. Considering extreme values, the highest values were found in site IV

*DOI: http://dx.doi.org/10.5772/intechopen.90878*

**Figure 3.** *Sulfate atmospheric deposition fluxes by site.*

*Mapping and Estimation of Nitrogen and Sulfur Atmospheric Deposition Fluxes… DOI: http://dx.doi.org/10.5772/intechopen.90878*

**Figure 4.** *Sulfate atmospheric deposition fluxes by land use.*

In the case of sites grouped with an urban land use, the mean value found was 14.05 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> , with a maximum and minimum values of 20.70 and 6.58 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> , respectively, observed in sites VI (Zoológico at NE) and site VII (Universidad de León) (**Figure 4**).

On the other hand, in the case of sites grouped with an industrial land use, the mean value found was 13.51 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> , with a maximum value of 25.82 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> . Considering extreme values, the highest values were found in site IV (Instituto Tecnológico de León at SE), whereas the lowest value (1.81 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> ) was registered in site III (monitoring station IMSS-T21 at downtown of the city).

### **3.2 Nitrate**

*Spatial Variability in Environmental Science - Patterns, Processes, and Analyses*

atmospheric deposition fluxes were found between seasons.

analyzed by site. A mean value of 13.78 Kg Ha<sup>−</sup><sup>1</sup>

whereas the minimum value (1.81 Kg Ha<sup>−</sup><sup>1</sup>

Industrial land use: Sites I, II, III, IV, V. Urban land use: Sites VI, VII, VIII, IX, X.

character of sulfate precursor (SO2).

year<sup>−</sup><sup>1</sup>

*3.1.2 Spatial variability*

value of 25.82 Kg Ha<sup>−</sup><sup>1</sup>

*3.1.3 Analysis by land use*

during the rainy season.

season, suggesting that the lack of dilution during this season could result in higher values in the region. Applying the Friedman tests, significant differences in sulfate

To assess the spatial distribution, sulfate atmospheric deposition fluxes were

year<sup>−</sup><sup>1</sup>

mean value was found in site IV (Instituto Tecnológico de León) located at SE,

monitoring station IMSS-T21 is located just at downtown of the city. Considering extreme values, the higher fluxes were found for site IV; however, when Friedman test was applied, significant differences were not found. It suggests a certain homogeneity in sulfate deposition levels in the study region, which confirms the regional

To assess the variability of sulfate atmospheric deposition fluxes by land use,

According to **Figure 4**, it can be observed that mean sulfate deposition fluxes were slightly higher in sites with an urban land use; however, sites with an industrial land use showed extreme values. When Friedman tests was applied, significant differences between land use were not found. It demonstrates a spatial homogeneity that suggests the regional origin of sulfate as a result of long-range transport mainly

sampling sites were grouped according to the prevailing land use as follows:

year<sup>−</sup><sup>1</sup>

. From **Figure 3**, it can be observed that the highest

was found, with a maximum

) was registered for site III, where

**50**

**Figure 3.**

*Sulfate atmospheric deposition fluxes by site.*

#### *3.2.1 Seasonal variability*

From **Figure 5**, it can be observed that the higher nitrate deposition fluxes were obtained during cold dry season, with a mean value of 2.93 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> and a maximum value of 3.93 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> , which corresponds to site X (Loma Blanca, at SW). On the other hand, the mean value obtained for warm dry season was 0.78 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> with a maximum of 1.47 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> in site X (Loma Blanca at SW). Finally, during the rainy season, a mean value of 1.13 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> with a maximum value of 2.84 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> in site X (Loma Blanca at SW) and a minimum value of 0.22 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> in site V (Instituto de la Mujer at SE) were found (**Figure 5**).

Applying Friedman tests, significant differences were found between cold dry season and the other two sampling seasons.

#### *3.2.2 Spatial variability*

From the analysis by sampling site, a mean nitrate atmospheric deposition flux of 1.61 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> with a maximum value of 3.93 Kg Ha<sup>−</sup><sup>1</sup> year<sup>−</sup><sup>1</sup> was found. The highest value was observed in site X (Loma Blanca at SW) (**Figure 6**).

**Figure 5.** *Nitrate atmospheric deposition fluxes by season.*

**Figure 6.** *Nitrate atmospheric deposition fluxes by site.*

However, when Friedman test was applied, differences found were not statistically significant, suggesting a certain uniformity in the distribution of sources (especially mobile sources) and nitrate levels around study area.
