A study on the reconstitution of daily PM10 and PM2.5 levels in Paris with a multivariate linear regression model

The amount of time air spends over a region is linearly related to the regionʹs contribution in PM. The residence time of air masses over emission sources was the main criterion for the division in 15 regions-origins. Daily PM concentrations in Paris (France), were reconstituted by multiplying the air mass residence time for each-one of the 15 regions by a regression coefficient (Bk) expressing the ability of each region to enrich the daily PM concentrations. The comparison between observed and predicted values gave satisfactory results. Local regions contributed cumulatively more than 50% of PM2.5 and PM10 in an average daily basis, whereas the residing areas of air parcels were particularly located around the city. Due to the scarceness of eastern circulation, continental airflows were associated with few episodes of extreme aerosol contributions, whereas peak air mass residence time values were isolated above Germany.