Definition

Nitrogen oxide and sulfur oxide emissions contribute to atmospheric and freshwater acidification. Non-methane volatile organic compounds (NMVOC) emissions contribute to the formation of tropospheric ozone and summer smog. Thus, these categories of substances are material because they directly impact air quality.

Nitrogen oxide emissions from Solvay’s operations result mainly from the combustion of fossil fuels such as natural gas. They are expressed as the sum of nitrogen monoxide and nitrogen dioxide, excluding nitrous oxide (N₂O) that contributes to global warming but does not have any acidification impact.

Sulfur oxide emissions (SO_x) arise mainly from the combustion of anthracite or coal.

Non-methane volatile organic compounds are : volatile organic compounds (VOCs) with a standard boiling point below or equal to 250°C (EU Solvent Directive 1999/13/EC). NMVOCs are VOCs other than methane. Methane emissions from Solvay’s mining activity at Green River (Wyoming, United States) are not included. Their impact is integrated into the greenhouse gas emission indicator.

Management approach

Air quality is managed through the Health, Safety and Environment management systems deployed by sites in line with their regulatory requirements and those from the Group.

Solvay is committed to improving air quality at local and regional levels, in close cooperation with local stakeholders. In the framework of its environmental plan, Solvay focuses on the following pollutants: nitrogen oxides (NO_x), sulfur oxides (SO_x), and non-methane volatile organic compounds (NMVOC).

Indicators and objectives

Solvay’s objective:

Since the start of the environmental plan in 2015, the emission intensities for nitrogen oxides, sulfur oxides, and NMVOC have dropped by 57%, 63% and 49% respectively. These performance already outweigh the 2020 targets Solvay has set in 2015. 

Solvay’s nitrogen oxide emissions went down significantly since 2018 (- 1,507 tons or - 20%), further closing the gap with its peers in the sector despite the energy intensive nature of the Soda Ash and Derivative Global Business Unit activity. This progress was mainly achieved at the sites of Torrelavega in Spain (- 686 metric tons or - 9.1% at Group level), Paulinia in Brazil (- 439 metric tons or - 5.7%) and Devnya in Bulgaria (- 367 metric tons or - 4.9%). At Paulinia, the lower NO_x emissions are the consequence of a fuel switch from oil to natural gas and improvements on the natural gas burners. These actions have been undertaken to satisfy the requirements of a new Brazilian law. The improvement at Torrelavega is due to two coal boilers, which have been retro-fitted with DeNO_x systems in the spring and summer of 2019, respectively. The significant decrease of for NO_x in Devnya is due to the increased stream factor of the newest Circulating Fluidized Bed Boiler boilers. Since the start of the ongoing environmental plan (2015-2020), nitrogen oxide emissions decreased by 50% or about 13% per year. These changes have been achieved through investments in abatement technologies.

Solvay’s sulfur oxide emissions have been cut by a further 862 metric tons since 2018, representing an additional 23% improvement. This progress was mainly achieved on the sites of Torrelavega in Spain (- 623 metric tons or - 16.6% at Group level), Atequiza Jalisc in Mexico (- 178 metric tons or - 4.8%) and Paulinia in Brazil (- 109 metric tons or - 2.9%). A small increase was observed at the plant of Rasal in India (+ 58 metric tons or +1.5%). The improvement on Torrelavega is due to the implementation of a new desulfurisation system (SolvAir^®) on the coal boilers. The decrease at Atequiza is due to the lower production volume for one of the chemicals produced at that site. The contribution of Paulinia to the global decrease is due to the switch from oil to natural gas on one of their boilers. Since the start of the ongoing environmental plan (2015-2020), sulfur oxide emissions have decreased by 56% or about 14% per year. These changes have been achieved through investments in new boilers, new desulfurization units, and optimization of existing ones.

Compared to 2018, the NMVOC emissions from the Group have decreased slightly (- 143 metric tons or - 3.3%). This global change is the resultant effect of improvements, mainly at Green River (United States), Panoli (India) and Spinetta (Italy), and increases at Zhenjiang Songl (China), Greenville (United States) and Piedmont (United States). Green Rivers’ NMVOC emissions have been reduced thanks to an enhanced recovery of mine gas in heated process equipment. The decrease at Panoli (India) is the consequence of a lower demand for PEEK/PES polymers. And at Spinetta (Italy), the NMVOC reduction is the fruit of the implementation of a new CF₄ abatement technology. Since the start of the ongoing environmental plan (2015-2020), NMVOC emissions have decreased by 40% or about 10% per year. It should be noted that the majority of this reduction is due to the divestement of the Performance Polyamides businesses.

2019 key achievements

The improvements in emissions to air for the substances on which we focus are mainly the consequence of investments in new abatement technologies and a switch to more environmental friendly combustibles.