Rainwater chemistry of acid precipitation occurrences due to long-range transboundary haze pollution and prolonged drought events during southwest monsoon season: climate change driven

Abstract

The purposes of this research were to study the characteristics chemistry of pH, anions and cations in rainwater, and to identify the possible sources that contributing to the acid precipitation during southwest monsoon season with occurrence of extreme drought event. During the southwest monsoon season, it normally occurs along with haze phenomenon that every year will hit Southeast Asia. This condition will aggravate with high acidic particles in the atmosphere due to the prolonged drought. The analysed parameters which involved pH, anions (NO 3-, SO 4 2and Cl À) and cations (Ca 2þ , Mg 2þ , Na þ and K þ) were analysed using pH meter, Hach DR 2800, argentometric method and ICP-OES. From the findings, it showed that acid rain occurred during the southwest monsoon season with the range of pH values from 4.95 AE 0.13 to 6.40 AE 0.03 and the total average of pH 5.71 AE 0.32. Anions NO 3-, SO 4 2and Cl À were found to be the dominant compositions of the acid rain occurrences with higher concentrations detected. In overall, rural area recorded with higher acidity of precipitation at total average of pH 5.54 AE 0.39 compared to urban area at pH 5.77 AE 0.26. Rural area surprisingly recorded higher frequency occurrences of acid rain with pH lesser than 5.6 and below compared to urban area. As for public health and safety, all rainwater samples during the acid rain event were found exceeded the allowable limits of NWQS and WHO standards, that shown not suitable for skin contact, recreational purposes even for drinking purposes.

The Chemical Characteristics of Rainwater and Wet Atmospheric Deposition Fluxes at Two Urban Sites and One Rural Site in Côte d’Ivoire

“…At Korhogo, precipitation was slightly acidic, with 59% of the 83 rainfall samples having measured pH values below 5.6. This result is similar to the study of [97], where rural areas recorded higher acidity of precipitation (pH = 5.54 ± 0.39) compared to urban areas (pH = 5.77 ± 0.26). Abidjan precipitations presented a pH value comparable to cities such as Guiaba, Brazil (5.72), Lijiang City, China (6.07), and Ibuina, Brazil (6.23) [43,57,59], and Korhogo has a pH value similar to cities such as Limeira (5.62) [12] (Table 2).…”

Optimization of the Electrocoagulation Process with Aluminum Electrodes for Rainwater Treatment

“…Anthropogenic activities, such as the burning of fossil fuels from transportation or industrial activities, release sulfuric acid and nitric acid into the atmosphere, which are known as inorganic acids. Meanwhile, sources of rain acidity in rural areas come from volatile biogenic organic carbon emissions, such as formic acid, oxalic acid, isoprene, propene, acetic acid, formic acid, or oxalic acid (Payus et al, 2020).…”

“…The organic pollutants were also characterized as: 52 mg/L COD, 5.07 mg/L BOD, the poor biodegradability index was 0.097 and a turbidity of 8 NTU. The anthropogenic sources of organics, anions and cations can be from biomass burning, fossil fuel combustion, soil properties and rock weathering, including fertilizers, forest fires and wind-blown dust (Rastegari Mehr et al, 2019;Payus et al, 2020).…”

The chemical characteristics of rainwater and wet atmospheric deposition fluxes at two urban sites and one rural site in Côte d’ Ivoire

“…with values representing 7 %, 23% and 16 % of the source's contributions to the chemical content of rainfall in Abidjan, Lamto and Korhogo respectively. The relatively low organic acidity in Abidjan is likely related to the fact that in urbans areas, anthropogenic activities are the main contributors of acid rain (Radojevic and Harrison , 1992;Park et al, 2015;Payus et al, 2020).…”