Derk Bakker^1,, Ariba Ashgar¹, Ehtisham Gill¹, Sima Saleem¹

Vegetation as a sink of air pollutants is well known and models have been developed to describe the processes involved. Vegetation as a sink for air pollutants in one of the most polluted cities in the world, Lahore, Pakistan, has not yet been documented. Lahore is known as the ‘Garden City’ and a model was developed to estimate the role of green urban spaces (GUS) as a sink for air pollutants in the city. Several GUSs in Lahore were described, and tree and leaf area (LA) dimensions were measured. This information formed the vegetation input of the model. The deposition fluxes of the gaseous pollutants and the dry and wet deposition of particulate matter were calculated and then applied to the LA of the GUSs. The precipitated and absorbed quantities of pollutants were contrasted with the amount present in the atmosphere. It was found that even relatively small GUSs have a significant ability to reducethe atmosphericpollutant concentrations. However, when extrapolating these findings to the urban area of Lahore at large, this impact reduces significantly due to the lack of GUSs in Lahore. The pollution generated by the city of Lahore far exceeds what the existing vegetation can accommodate. The existing vegetation of the city therefore needs to be protected, and the area of GUSs increased because without such spaces the city is even worse off. The prevailing atmospheric conditions during the winter monthsdoes however, limit the effectiveness of the role of vegetation as a sink for air pollutants.

Green urban spaces, semi-arid area, pollutant absorption, pollutant deposition