The pollution status of sulfur dioxide was analyzed using the datasets collected from seven major cities in Korea for the period of 1989–2010. Although there were moderate differences in SO2 levels between the cities, the temporal trends were seen to be rather distinctive between seasons or across the years. The SO2 levels consistently exhibited relative dominance during winter due to the combined effects of domestic heating and meteorological conditions. In contrast, the annual datasets underwent an abrupt decrease until the late 90s. As such, if the data are divided into two periods I (1989–1999) and II (2000–2010), the mean values were reduced considerably from a few tens of ppb (period I) to a few ppb levels (period II). This notable change is suspected to reflect the effect of gradual shift in fuel consumption patterns (e.g., from conventional fuels to cleaner renewal sources of energy). The results of the principal component analysis (PCA) indicated that emissions of SO2 are affected by the incomplete combustion of fossil fuels. According to the health risk assessment, the SO2 exposure to infants and adults should have decreased significantly from period I to period II (e.g., by 5–7 times).