CHEMICAL CHARACTERISTICS OF RAINWATER IN BANDUNG AND GAW BUKIT KOTOTABANG

1Fandy Balbo, S.Si. 2Dr. Rusmawan Suwarman, S.Si., MT.3Arika Indri Dyah Utami, M.Si.

1Undergraduate of Departement of Meteorology, Bandung Institute of Technology2Research Group of Atmosphere Science, Bandung Insitute of Technology

3Center for Applied Climate Information Services, The Indonesia Agency for Meteorological, Climatological, and Geophysics

Departement of MeteorologyFaculty of Earth Science and Technology

Bandung Institute of Technology

• Cations and Anions variations are not affected by seasonal condition. However,cation and anion concentration strongly influenced by the current precipitation.

• Cations are not effective to neutralize the pH value of the rainwater, the value isstill acidic.

• Pollutants in GAW Bukit Kototabang is coming from long-range transportpollutants. While Bandung’s pollutants are coming from local anthropogenicactivities and long-range transport pollutants.

Precipitation is an efficient pathway for removing gases and particles fromatmosphere. Gases incorporated into them are the oxides of Sulphur andnitrogen, which are chemically converted into sulfuric acid and nitric acidwhich are responsible for occurrence of acid rain (Tiwari et al, 2006).

Two events were recorded acid rain from 28 rain events in urban site(Kulshresta et al, 2003). Ca2+ acts as a neutralizer and pollutants from localanthropogenic activities (Khashman, 2008).

High concentration of SO42- associated with Ca2+ in rural site (Ali, 2005).

Samples of rainwater can record the chemical processes in atmosphereand respons to air quality environment problems (Budiwati, 2016).

Further research is needed in Bandung (urban site) and GAW BukitKototabang (rural site) to determine the pollution and air quality throughthe chemical composition of rain water.

Background

Methods

Results

a) b) c) d)

a)d)

b) c)

• Low precipitation accumulatedin SON (Bandung) induces highconcentration of SO4

2- and NO3-.

• Anthropogenic activities are notdependent on seasonalconditions, so that a highconcentration pollutantsdissolved in low precipitation(SON).

• Low precipitation accumulatedon DJF ( Bukit Kototabang)induces SO4

2- highconcentration.

• The chemical concentration ofrainwater will be lower if theprecipitation increased. Law ofthe Dilution Effect applied.

Relative Contribution BandungGAW Bukit Kototabang

nssSO42- (%) 54.37 61.69

NO3- (%) 45.63 38.04

EFc Mg2+/Ca2+ K+/Ca2+ Cl-/Ca2+ SO42-/Ca2+ NO3

-/Ca2+

Bandung 0.22 0.25 114.93 107.87 971.66Kototabang 0.27 6.04 1007.70 318.95 1833.24

Analysis of Variation

Analysis of Acidity

• Normal rainwater has a pH of 5.6 (slightly acidic). This isbecause it is exposed to the carbon dioxide in theatmosphere. In Bandung, the pH of rainwater below 4.50 whilein Kototabang, pH of rainwater below 4.80.

• The rate of neutralization by Ca2+ (0.32), with FA=0.012 and rateof neutralization by K+ (1.13), and FA=0.018. Both showedineffective neutralization

• High pollutant concentrations of SO42- and NO3

- caused therainwater become acidic in Bandung.

Source Identification • EF Mg2+ and K+ -> Crust.

• EF Cl- and Mg2+ -> Sea spray.

• EF SO42- and NO3

- indicated high around the sample point.

Discussion

• BandungFactor 1 (Natural Source).Factor 2 (Local Anthropogenic Source).Wedge Factor (Long Range Transport Pollutants).

• GAW Bukit KototabangFactor 1 (Natural Source) (Long Range Transport Pollutants).Factor 2 (Local Anthropogenic Source).

Conclusion

EFs Ca2+/Na+ Mg2+/Na+ K+/Na+ Cl-/Na+ SO42-/Na+ NO3

-/Na+

Bandung 62.69 1.50 15.58 0.85 46.62 281412.91Kototabang 21.70 0.64 132.20 2.57 47.72 183812.47

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Kulshrestha, U., Kulshresta, M. J., Sekar, R., Sastry, G., dan Vairamani, M. (2003). Chemical characteristic of rainwater at an urban site of south- central India. Atmospheric Environment .

Momin, G., Ali, K., Rao, P., Safai, P., Chate, D., dan Praveen, P. (2004). Study of chemical composition of rain water at an urban (Pune) and a rural (Sinhagad) location in India. Journal of Geophysical Research.

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Xiao, J. (2016). Chemical composition and sources identification of rainwater constituents at an urban site in Xi'an. Environment Earth Science.

References

NF Ca2+ Mg2+ K+ NH4+

Bandung 0.35 0.04 0.05 0.04

Bukit Kototabang 0.24 0.03 1.13 0.27

Recomendation

Air quality management

SO2purification from industry

Efective in dry season

Reduce the potential acid rain events