Comparative Analysis of Water Vapor Composition at Selected Sites

The potential for the use of water vapor as an air quality indicator
was investigated. Water vapor samples were collected from three urban sites (roadside, landfill, residential) and an agricultural area, using a simple active cooling system. They were analyzed for standard water quality parameters. Results showed significant differences in pH, with slightly acidic water vapor samples in the urban sites compared to the neutral pH of the control. The value for total dissolved solids (TDS) was lowest in the agricultural area, although the differences for TDS were less pronounced. The landfill station registered the highest chemical oxygen demand (COD) levels, possibly indicating the effect of the decomposition of organic matter. Nitrate levels were significantly higher in the urban sites, particularly at the roadside station, most likely due to traffic emissions. Variations in sulfate levels were not significant, suggesting that tropospheric chemistry may be more important than emissions in influencing its presence in vapor. In general, water vapor composition appears to be sensitive to the expected differences in air quality among the sampling stations.

[Loyola Schools Review, 2005]