For over 20 years International Day for the Preservation of the Ozone Layer has been celebrated every 16 of September in remembrance of the Montreal Protocol that was signed in 1987. In the late, ’80s but mainly in the ’90s, the threat to the stratosphere by high levels of harmful gases in the atmosphere was no longer a matter for experts but became a concern for the general public. Perhaps young people do not remember this, but it was not really until those years that society became truly aware of the effects of pollution on our planet.

Perhaps we should ask ourselves whether annual meetings such as the Montreal Protocol actually serve to change things. The answer is yes. Today, almost three decades after that first meeting, the emission of 135,000 tonnes of CO² has been avoided thanks to the reduction and banning of products listed by the UN containing polluting chemical substances that destroy the ozone layer. For the first time ever we can actually say that we are much closer to achieving the complete restoration of the ozone layer.

In that particular case, social alarm was key to global mobilisation but that does not mean we can now rest on our laurels. In recent years, concern has shifted from the stratosphere to a dimension that is much closer to home: according to World Health Organization data, outdoor air pollution is choking the main capitals of the world and poor air quality affects 80% of its citizens.

Medium and long-term emergency plans that have been introduced in cities such as Madrid, Barcelona and New York are already beginning to show results. An example of this is the replacement of traditional industrial and domestic heating systems with more efficient methods. In this context, natural gas has played a transformative role, as coal has been replaced by natural gas condensing boilers that emit up to three times less nitrogen oxide into the air, as explained in this article in the Sedigas GasActual magazine ().

Local governments have become key allies in the fight against climate change and, in many cases, they have especially championed the cause to improve air quality. As Gasnam reveals in this study, over 5,000 vehicles in Spain run on natural gas, of which 33% are city buses, 28% are waste collection lorries, and 15% are taxis and light vehicles for urban passenger transport. This not only reduces toxic emissions but it also reduces the presence of suspended particles in the air that are closely linked to the increase in respiratory diseases such as chronic obstructive pulmonary disease (COPD). According to the Spanish Society of Pneumology and Thoracic Surgery (SEPAR), 2 million people in Spain suffer from COPD although 70% of them are not aware of it as they have not been diagnosed.

The idea of eco-cities was first put forward in 1975, but it was not until the second millennium that town councils have become truly aware of the need to promote sustainable urban growth. Natural gas does not release particles that are suspended in the air; it reduces emissions of greenhouse gases; and, in combination with other energies such as electricity, it is able to almost entirely eliminate the production and release of sulphur oxides into the atmosphere. The strategic plans of cities such as Madrid and Barcelona to reduce levels of pollution therefore include investment in technologies that are fuelled by natural gas.

If you would like to learn more about this topic, I invite you to read this report published by the International Gas Union that shows the positive effects of the relationship between the use of natural gas and reduced urban pollution levels.