Base cations such as magnesium are important in the environment because deposition has an impact upon surface pH, causing an increase in alkalinity, thereby buffering or neutralizing the effects of acidity generated by sulphur and nitrogen. It is for this reason these emissions are of interest, rather than their negative impacts upon human health or ecosystems. It was long assumed that the major source of base cations in the air was dust from soil erosion, but patterns of concentrations in air and precipitation also suggest significant emissions from urban and industrial sources.
Emissions of magnesium have fallen by 83% since 1990, mainly due to a reduction in emissions from solid fuel use. The most significant source of magnesium emissions in 2021 were construction and fireworks which were responsible for 35% and 12% of UK emissions respectively.