< Volatiles Organic Compounds - VOCs Sulphur dioxide - SO2 >

Associated topic: acidification

Emissions monitoring period: since 1980

Data source: CITEPA / SECTEN format - April 2017

 

Origin of the indicator

The acid equivalent index (Aeq) has been developed to measure the overall quantity of air emissions that contribute, to a varying extent over time and depending on geographical scales, to acidification on land, in water and in the air.

The index is calculated on the basis of potential fixation of the H+ ion. Only sulphur dioxide (SO2), nitrogen oxides (NOx) and ammonia (NH3) are taken into account, as a quick calculation shows that because emission levels of the other acidifying substances, such as hydrochloric acid (HCl), are low compared to the three substances mentioned above, they contribute only marginally to acidification. The following weighting coefficients are used in the calculations: 0.0313 for SO2, 0.0217 for NOx and 0.0588 for NH3.

 

Emissions and trends

Minimum observed: 63 kt in 2015
Maximum observed: 184 kt in 1980
Emissions in 2015: 63 kt
Trends 2015/1980: -65.9%
Trends 2015/1990: -49.3%
Trends 2015/maximum: -65.9%
Trends 2015/minimum:  0%

Measurement unit: kt (kilotonne)

Source CITEPA / SECTEN format – April 2017

 

Analysis

The graphs below show that the relative proportions of the pollutants included in the index (Aeq) have changed over time.

The changing share of each pollutant in the index is partly due to the fact that... (to read more, consult the SECTEN report online via your login and password)

 Graph Aeq Anneaux 17

Graph Aeq Courbes 17

Tab Aeq 17

(*) Following UNECE/NEC definitions : emissions classified "except total" are not included, i.e. emissions from international maritime, emissions from domestic and international air transport cruise (≥ 1000 m), emissions from agriculture and forestry biogenic sources and emissions from non-anthropogenic sources.
(**) Aeq : acid equivalent calculated on the basis of potential fixation of the H+ ion : 0.0313 for SO2, 0.0217 for NOx and 0.0588 for NH3.
(e) preliminary estimate

 

Data source: CITEPA / SECTEN format - April 2017