Fitting the probability distribution functions to model particulate matter concentrations

الملخص EN

The main objective of this study is to identify the best probability distribution and the plotting position formula for modeling the concentrations of Total Suspended Particles (TSP) as well as the Particulate Matter with an aerodynamic diameter <10 μm (PM10).

The best distribution provides the estimated probabilities that exceed the threshold limit given by the Egyptian Air Quality Limit value (EAQLV) as well the number of exceedance days is estimated.

The standard limits of the EAQLV for TSP and PM10 concentrations are 24-h average of 230μg/m3 and 70μg/m3, respectively.

Five frequency distribution functions with seven formula of plotting positions (empirical cumulative distribution functions) are compared to fit the average of daily TSP and PM10 concentrations in year 2014 for Ain Sokhna city.

The Quantile-Quantile plot (Q-Q plot) is used as a method for assessing how closely a data set fits a particular distribution.

A proper probability distribution that represents the TSP and PM10 has been chosen based on the statistical performance indicator values.

The results show that Hosking and Wallis plotting position combined with Frechet distribution gave the highest fit for TSP and PM10 concentrations.

Burr distribution with the same plotting position follows Frechet distribution.

The exceedance probability and days over the EAQLV are predicted using Frechet distribution.

In 2014, the exceedance probability and days for TSP concentrations are 0.052 and 19 days, respectively.

Furthermore, the PM10 concentration is found to exceed the threshold limit by 174 days.