Analysis of NO_x, NO and NO₂ ambient levels as a function of meteorological parameters in Dhahran, Saudi Arabia

NO_x, NO and NO₂ concentrations, and meteorological parameters, temperature, wind speed, relative humidity and pressure were measured simultaneously and continuously in Dhahran (Saudi Arabia) during three months in summertime. The hourly and daily NO_x, NO and NO₂ average concentrations were investigated as a function of the meteorological parameters. NO_x, NO, and NO₂ were found to have a common source and to be highly influenced by traffic emission and meteorological conditions, and the trend of NO showed a higher concentration during weekdays than weekends. NO_x has significant positive correlation coefficients with NO and NO₂, respectively. Similarly, NO₂ also has a positive correlation coefficient with NO. The temperature and wind speed showed negative correlation coefficients while relative humidity showed positive correlation coefficient with NO_x, NO and NO₂. On the other hand, NO₂ was found to exceed international air quality standards, which indicates the existence of a possible NO₂ air pollution problem in Dhahran.