Prediction of atmospheric sulphate deposition at sensitive receptors in northern India

Soil-derived particles in suspended particulate matter (SPM) are reported to be responsible for acid rain neutralization in India. A study on the seasonal variability of SPM indicates that the winter season SPM levels are significantly less than the summer season SPM levels thereby suggesting the winter season to be critical for acid rain. Therefore, SO4 deposition is examined for the winter season at sensitive receptors in northern India using a long-range air transport model. The UW-LRT model is employed to estimate the SO4 deposition levels at six locations given the point source emission quantities from 12 major sources. The model results match favourably with literature-reported deposition levels. The model results argue for a well-designed monitoring program for measurement of sulphate deposition to better determine the extent of the problem and model calibration.