Characterizinig precipitation chemistry in Changhua, Central Taiwan using weather conditions and multivariate analysis

Few studies of atmospheric deposition come from the fast growing region of Southeast Asia. Precipitation in Changhua City in central Taiwan was collected to examine its chemical composition and relationship with meteorological patterns. Fifty percent of the precipitation measurements had pH<5.0. Deposition fluxes of most ions were comparable to that reported for heavily industrialized temperate regions. Storms associated with air masses which originated in China had higher ion concentrations than other storms, suggesting substantial contribution of long-range transport. Two factors, a sea salt factor and an anthropogenic factor, explained more than 70% of the variation in precipitation chemistry. A third factor had a high loading only on H ⁺, suggesting that pH of precipitation in Changhua City was not dominated only by acidic or basic ions alone. Instead it is determined by all components. The influences of soil and dust, as indicated by high loading on Ca²⁺ and K⁺, cannot be recognized without sea salt correction.