Evaluation of hourly-based precipitation chemistry in suburban site of Bolu

Özet

Precipitation chemistry is important for understanding atmospheric chemistry and transportation mechanism fora region. Therefore, 6-h rain samples were collected manually on the Black Sea Region of Turkey between March2019 and May 2019. Totally, 21 wet deposition samples were collected in 12 rainy days. The collected rainsamples were analyzed by ion chromatography for ions, including Cl−,NO2−,NO3−,SO42−,Na+,Ca2+,Mg2+,K+,NH4+. Volume weighted mean (VWM) concentrations of ions were calculated and were in the order ofNa+>Ca2+>Cl−>SO42−>NO3−>Mg2+>K+>NH4+>NO2−. The pH values of individualprecipitation varied from 4.70 to 8.07. Anion to cation ratio was 0.74 ± 0.34 thus it was an indication of aniondeficiency. A strong correlation between NH4+and SO42−,NH4+and NO3−,Ca2+and SO42−,Ca2+, and NO3−was found in the samples due to the neutralization process. The back trajectory model was used tofind the long-range sources and the influence of air masses coming from Saharan, Europe, and the Black Sea. Calcium ion wasfound to be an effective ion in the neutralization processes by analysis of multiple linear regression and neu-tralization factor calculation. Approximately 79.5% of SO42−and 59.7% of NO3−were neutralized by Ca2+andNH4+. The washout mechanism for Na+,Mg2+,Ca2+, and K+was dominantly observed on the March 12, 2019.Rainout mechanism was seen on the April 13, 2019 rain event due to the long-range transportation from SaharanDust.