تحديد التغير المكاني لملوثات الغلاف الجوي بمكة المكرمة

Abstract

There is a high interest in quantifying temporal trends in air pollutant concentrations as they serve to assess the effects of emission control strategies. In this paper temporal trends (1997 – 2012) in air pollutant concentrations in the City of Makkah, near Al-Haram have been assessed with the help of TheilSen approach and changepoint analysis, which are applicable to both normal and non-normal distributed data and are therefore preferred over parametric statistics. Trend analysis of nitrogen oxides (NOx), nitric oxide (NO), nitrogen dioxide (NO2), carbon monoxide (CO), sulphur dioxide (SO2), particulate matter with aerodynamic diameter of 10 micron or less (PM10) and ozone (O3) was performed not only at mean concentrations but also at several selected quantiles (Minimum, first quartile, median, third quartile and maximum) . TheilSen function revealed significant positive trends in SO2, NO2, PM10 and ozone concentration and negative trends in CO and NO. Trends vary at various metrics suggesting different behaviour of air pollutants at various quantiles of the distribution. Reasons for the reported temporal trends are discussed. Further work on source apportionment of various emission sources and their temporal trend is required, which will provide further insight into the causes behind the trends of air pollutants and help better manage air pollutant levels in Makkah and elsewhere in the country. Keywords: temporal trends, Makkah, Saudi Arabia, air pollutant trends, air quality.