What Pollutants Are Measured in the Air? - Sulphur Dioxide

Sulphur dioxide (SO2) is the most prevalent of all sulphur oxides. It is created during the combustion of materials containing high sulphuric content and has been proven to have damaging impacts upon human health and the natural world.

The biggest contributors to SO2 contamination have historically been heavy industry, though the decline of that sector, alongside stricter controls on SO2 emissions, have seen concentrations fall dramatically in recent years. Thankfully, levels of SO2 are no longer considered sufficiently high to endanger plant health, though the gas remains a leading ingredient in the formation of particulate matter (PM) and urban smog.

Where does sulphur dioxide come from?

SO2 is primarily created when materials containing high levels of sulphur are combusted. Coal, coal derivatives, fuel oil and petroleum coke are all notorious for having an elevated sulphuric content in comparison to other types of fuels. As well as coal-fired power plants and industrial processes which rely on the combustion of those materials, sulphur dioxide is a by-product of extracting metal from ore.

Meanwhile, transportation does play a role in the generation of SO2. While passenger cars and other, smaller vehicles generally do not rely on fuel sources which contain a lot of sulphur, larger vehicles like locomotives and cargo vessels do. Over the years, the primary sources of SO2 (like coal power plants) have been phased out, meaning transportation now accounts for a bigger share of SO2 emissions than ever before.

The biggest changes occurred during the 1970s and 1980s, when the UK transitioned from its dependence on manufacturing (particularly iron and steel) to a more service-based economy. The miner’s strike in the early 80s also signalled a sea change away from coal as a primary energy source, so emissions have fallen sharply since then. Indeed, SO2 emissions in the UK have declined by an astonishing 95% since 1990.

What harmful effects can sulphur dioxide have?

At high concentrations, sulphur dioxide can have extremely detrimental impacts on the environment. Not only have coal-fired power stations been linked with extreme rainfall events – including acid rain, which can damage ecosystems – but an excess of SO2 in the atmosphere can inhibit the growth of vegetation and cause damage and discolouration of foliage.

In terms of human health, SO2 stimulates the nerves in the lining of the throat. This manifests itself in irritation of the throat and lungs, bouts of irresistible coughing and difficulty breathing. Those who already suffer from asthma are particularly susceptible to sulphur dioxide and may experience constriction in their chest and tightness in their airways.

While SO2 is not known to be deadly alone, it is a chief ingredient in the creation of PM. This contaminant is known to be one of the most dangerous to man and is small enough to be inhaled and even infiltrate the bloodstream. Though its most severe effects are not fully understood, it is thought to damage the internal organs and potentially spark cognitive or mental difficulties of the individual in question.

For more information on sulphur dioxide, particulate matter and all other types of emissions and contaminants, Poland will be hosting a virtual edition of next year’s CEM conference in March. Each of those topics (and many more!) will be discussed in far greater detail, providing a unique insight into the subject for interested parties.