Monday, February 10, 2020

Large sulfur plumes over Wuhan and other central provinces with flu outbreak







What are the effects of sulphur oxides on human health and ecosystems?

95% of the SOx emitted from the combustion of fossil fuel is sulphur dioxide. SO2 is a toxic gas, which is directly harmful to human health. It is heavier than air and has a suffocating odour at an atmospheric concentration of around 500 parts per billion (ppb), at which level it can be fatalAt lower levels, chest pains, breathing problems, eye irritation and a lowered resistance to heart and lung diseases can be experienced. At 20 ppb or lower there should be no ill effects to a healthy person. The normal atmospheric background concentration of SO2 is generally less than 10 ppb. [3]
A secondary effect is the formation of sulphates (and nitrates), in the form of aerosols or very fine airborne particles, which can comprise a significant proportion of the particulate matter and have been linked to increased asthma attacks, heart and lung disease and respiratory problems in susceptible population groups. [3]
A third effect can occur further away from the emission source where the sulphur oxides will have converted to acids by aqueous phase reactions in the atmosphere. These acidic aerosols are eventually precipitated as acid rain, snow, sleet or fog but only when they encounter the right meteorological conditions. In the absence of man made pollution rain water would be slightly acidic, around pH 5, due to the presence of carbonic acid from the interaction of water vapour and naturally occurring levels of CO2. Acid rain on the other hand has been measured with pH levels below 3 corresponding to vinegar. [3]