Assessment of particulate matter concentration and gaseous pollutants in urban and rural regions over the Emirate of Abu Dhabi, UAE

In order to understand the air quality and plausible sources of atmospheric pollutants over the Emirate of Abu Dhabi (EAD), a detailed analysis is performed by utilizing three years of simultaneous measurements of various gaseous pollutants such as SO2, NO2, CO, and O-3 along with PM2.5 and PM10 concentrations during the period 2011-2013. The diurnal variation of O-3 and SO2 shows noontime maximum in urban and rural regions during all seasons, while NO2 and CO show higher levels in the morning and evening. During winter, maximum (minimum) O-3 (NO2) is observed in the rural region and in contrast, the urban region depicts maximum in spring and summer both during day and night. Large variability is observed during the day and night for all pollutants. The PM(2.5 )concentration shows similar diurnal variation as in the case of CO and NO2, peaking during daytime in winter and spring in the urban region, while the nighttime peak values are prominent irrespective of the season. It is also to be noted that the minimum (maximum) PM10 values are observed in the urban (rural) regions during daytime in all seasons except in winter. The frequency distribution of the hourly mean concentrations of the primary pollutants in the urban and rural regions elucidates that the observed discrepancies in the background concentration levels of different pollutants may be due to different atmospheric conditions. The observations also reveal that the linear relationship between maximum ozone concentration and maximum temperature might not be valid above 313 K. The present observations are discussed in the light of current understanding of the distribution of trace species and plausible sources over EAD region.