Reconstructing past atmospheric pollution levels using gravestone erosion rates

Converting the erosion rates derived from gravestones into erosion rates for specific time periods is possible by averaging loss data for gravestones for that time period. This information can be used with Lipfert's damage function to postdict levels of atmospheric pollution for specific locations for specific time periods. A correction factor for stone type, derived from the literature, needs to be applied to the damage function. The derived sulphur dioxide (SO2) levels are likely to represent atmospheric pollution conditions 20 years after the time period to which the erosion rates refer, because there is a lag in the response of the gravestone erosion to environmental conditions. With these correction factors applied, distinct temporal trends can be identified in both Oxford and Swansea, specifically a rapid increase in atmospheric SO2 in the early 20th century, a distinct dip in levels during the 1940s and a dramatic rise in the 1950s. In addition, there is a clear urban/rural difference in derived SO2 levels, with levels in urban Oxford being significantly higher than those in rural Oxford throughout the period of data availability. The significance of industrial activity is clearly illustrated by the very high levels of derived SO2 in Swansea throughout the early to mid 20th century.