A study on the diurnal and seasonal formaldehyde's concentration variations in ambient air of Enghelab Square region in Tehran, 2014-2015

Formaldehyde is one of the most important aldehydes in ambient air which originates from vehicles and photochemical processes. Because of the importance of this pollutant in public health, in this study, we addressed the concentration level in coupled with daily and cross sectional variation of formaldehyde in the high traffic area of Enghelab Square in Tehran. Also the effect of meteorological parameters on variation of formaldehyde concentration was determined.
This cross-sectional study was done in Enghelab Square placed in the district 6 of Tehran in December, January and February (period 1) and April, May and June (period 2) in 2014-2015. To measure the concentration of formaldehyde, the chromotropic acid method was used. Samples were analyzed by spectrophotometer Perkin Elmer UV-Vis LAMBDA 25 at wavelength 580nm.
The results show that there is a significant difference between the formaldehyde concentration on Fridays and that in other days during a week (T-test, p The Formaldehyde concentration on Fridays in comparison with other days is lower. This can be due to the low traffic volume on Fridays. Moreover, increasing formaldehyde concentration in the period 2 in comparison to period 1 is the result of intensifying photochemical processes in the warm months. Also the effect of temperature, humidity and inversion condition on increasing the concentration of formaldehyde show the importance of meteorological conditions in formaldehyde concentration variations.