Determination of nitrogen dioxide, sulfur dioxide, ozone, and ammonia in ambient air using the passive sampling method associated with ion chromatographic and potentiometric analyses

摘要

Concentrations of nitrogen dioxide (NO_2), sulfur dioxide (SO_2), ozone (O_3), and ammonia (NH_3) were determined in the ambient air of Al-Ain city over a year using the passive sampling method associated with ion chromatographic and potentiometric detections. IVL samplers were used for collecting nitrogen and sulfur dioxides whereas Ogawa samplers were used for collecting ozone and ammonia. Five sites representing the industrial, traffic, commercial, residential, and background regions of the city were monitored in the course of this investigation. Year average concentrations of <59.26, 15.15, 17.03, and 11.88 ng/m~3 were obtained for NO_2, SO_2, O_3, and NH_3, respectively. These values are lower than the maxima recommended for ambient air quality standards by the local environmental agency and the world health organization. Results obtained were correlated with the three meteorological parameters: humidity, wind speed, and temperature recorded during the same period of time using the paired t test, probability p values, and correlation coefficients. Humidity and wind speed showed insignificant effects on NO_2, SO_2, O_3, and NH_3 concentrations at 95% confidence level. Temperature showed insignificant effects on the concentrations of NO_2 and NH_3 while significant effects on SO_2 and O_3 were observed. Nonlinear correlations (R2≤ 0.722) were obtained for the changes in measured concentrations with changes in the three meteorological parameters. Passive samplers were shown to be not only precise (RSD≤ 13.57) but also of low cost, low technical demand, and expediency in monitoring different locations.