  In this report, the evolution of PM2.5 concentration at Escuelas Aguirre
monitoring station during the quarters of 2019 and the significance of the
differences with the concentration of the quarters of previous years is
analysed. These periods include the activation of Madrid Central, which is a
major initiative for reducing motor traffic and the associated pollution at the
city centre. These periods correspond to the initialisation of, 2019Q1; and to
tree fully-operational quarters of Madrid Central, 2019Q2, 2019Q3 and 2019Q4.
Escuelas Aguirre monitoring station is not inside Madrid Central but 2 km away.
The analysis of the PM2.5 concentration at this station allows discerning the
rise of negative effects due to an increment of the motor traffic around the
traffic restricted area. The analysis is based on the Binomial Sign Test for a
Single Sample. The sample of signs is generated by subtracting the daily mean
concentration of PM2.5 for the measurements of the period of two years: 20xx
and 2019. Samples for the pair-wise comparisons for the year 2019 versus the
years of the periods from 2010 to 2018 are evaluated. An excess of positive or
negative sign indicates that the differences between the measurements of
concentrations in the comparison of two years are significant. Conversely, a
balanced number of positive and negative signs points to no impact of the
action. Since wind is an efficient pollution remover, the Binomial Sign Test is
also applied to its intensity in the two-periods comparison. This allows
discerning if the pollution reduction could be associated to a larger number of
windy days in the 2019 quarter under comparison.
