What is it?

The emission of substances, gases and particles into the atmosphere can affect air quality, the stratospheric ozone layer and the climate system. The effects depend on the properties of the substances, the amount emitted, their persistence and transformation in the atmosphere, and the conditions of exposure.

Ambient air pollution affects human health and ecosystems. Among the pollutants of greatest relevance are particulate matter (PM10 and PM2.5), nitrogen dioxide (NO₂), sulphur dioxide (SO₂), ground-level ozone (O₃), carbon monoxide (CO), benzene, lead, arsenic, cadmium, nickel and certain polycyclic aromatic hydrocarbons. European and Spanish legislation establishes objectives, limit values, target values, information and alert thresholds, and requirements for the assessment and management of ambient air quality.

Air pollution does not affect the general population alone. Particularly sensitive people and vulnerable groups may face a higher risk from certain pollutants. WHO scientific evidence shows adverse health effects even at concentrations below those covered by previous air quality guidelines.

Depletion of the stratospheric ozone layer increases the amount of ultraviolet radiation reaching the Earth's surface. Ozone-depleting substances include certain halons, chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), carbon tetrachloride, methyl chloroform, methyl bromide and other substances covered by international and European legislation. Current European legislation regulates these substances through Regulation (EU) 2024/590.

For the classification and labelling of substances and mixtures, the CLP Regulation establishes the hazard class “Hazardous to the ozone layer”, Category 1, with hazard statement H420.

Climate change is linked to the increase in atmospheric concentrations of greenhouse gases. Human activities, mainly through greenhouse gas emissions, have unequivocally caused the observed global warming. The IPCC reports that climate change impacts are already affecting numerous regions and natural and human systems.

The main greenhouse gases include carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O) and certain fluorinated gases. In the European Union, fluorinated gases are subject to specific requirements on emissions prevention, leak control, recovery, placing on the market and progressive substitution under Regulation (EU) 2024/573.

Protecting the atmosphere therefore requires action at the source of emissions, prevention of leaks and fugitive emissions, substitution of substances and processes where technically feasible, and the implementation of energy efficiency, sustainable mobility and emission-reduction measures.

What can be done?

General measures

1. Request information on the company's atmospheric emissions, their sources, the substances emitted, quantities and control measures.
2. Identify activities that may pollute the atmosphere and the applicable permits or requirements.
3. Give priority to preventing and reducing emissions at source.
4. Propose replacing emitting substances and processes with alternatives that reduce hazard and emissions.
5. Avoid fugitive emissions, leaks and losses during storage, use, maintenance and waste management.
6. Request information on the results of measurements, controls and emission-reduction programmes.

Ozone-depleting substances

1. Check whether substances regulated by Regulation (EU) 2024/590 are present in equipment, installations, processes, products or waste. Regulation (EU) 2024/590.
2. Identify possible leakage points and establish prevention, detection and repair measures.
3. Ensure the recovery and proper management of substances and equipment where applicable.
4. Avoid the deliberate or accidental release of regulated substances.
5. Give priority to replacing them with technologies and substances that do not deplete the ozone layer.
6. In refrigeration, air-conditioning, fire-extinguishing and other equipment, also check whether fluorinated greenhouse gases subject to Regulation (EU) 2024/573 are present.

Substances and gases contributing to climate change

1. Request information on greenhouse gas emissions and, where applicable, emissions expressed in tonnes of CO₂ equivalent.
2. Identify equipment and processes using fluorinated gases and check the applicable obligations.
3. Prevent and control leaks of fluorinated gases.
4. Propose energy-efficiency programmes and reductions in energy consumption.
5. Promote the progressive replacement of emission-intensive technologies with alternatives having a lower climate impact.
6. Promote mobility systems that reduce unnecessary use of private vehicles.
7. Promote renewable energy use and electrification where technically and economically feasible.
8. Where the installation is covered by the emissions trading system, request information on its monitoring, verification and allowance-surrender obligations.

Spanish climate legislation is structured, among other instruments, around Law 7/2021 on climate change and the ecological transition, whose consolidated version was updated on 30 June 2026.

Ambient air pollutants

1. Request information on pollutants emitted by the installations.
2. Identify sources of particulate matter, NOx, SO₂, VOCs, NH₃, metals, polycyclic aromatic hydrocarbons and other relevant pollutants.
3. Propose measures to reduce emissions at source.
4. Prioritise enclosed processes, local exhaust ventilation, filtration and other effective emission-reduction measures.
5. Replace products and processes that generate significant emissions where technically feasible alternatives exist.
6. Pay particular attention to emissions of fine particulate matter and pollutants with carcinogenic or respiratory effects.
7. In the event of pollution episodes or exceedances of established values, apply the measures provided for by the competent authorities.

Spanish legislation also establishes national emission-reduction commitments for SO₂, NOx, NMVOCs, NH₃ and PM2.5.

Guidance and reference publications

1. Ministry for the Ecological Transition and the Demographic Challenge (MITECO): official assessment and air-quality data for Spain.
2. Spain's 2024 Air Quality Assessment Report, currently the latest annual report available on the official MITECO website (MITECO).
3. European Environment Agency (EEA): Air Quality Status Report 2025, with the latest available European data and a comparison with current standards and the new 2030 standards.
4. WHO Global Air Quality Guidelines, 2021, as a health-based scientific reference for PM₂.₅, PM₁₀, O₃, NO₂, SO₂ and CO.
5. IPCC: Climate Change 2023 – Synthesis Report, as an international scientific reference on climate change, impacts, risks and mitigation.
6. UNEP/WMO: Scientific Assessment of Ozone Depletion 2022, a scientific reference within the Montreal Protocol system on the state of the ozone layer.

Classification

Ozone layer

The list includes ozone-depleting substances regulated by Regulation (EU) 2024/590, including the groups and substances specified in its annexes.

The classification should be updated directly from the current annexes to the Regulation and not from the former Regulation (EC) 1005/2009. Regulation (EU) 2024/590 expressly repealed the latter.

Climate change

The list includes substances and gases relevant to climate change, distinguishing, where appropriate:

1. greenhouse gases regulated under the international climate regime;
2. greenhouse gases covered by European and Spanish legislation;
3. fluorinated gases specifically regulated by Regulation (EU) 2024/573;
4. substances with significant global warming potential.

Air quality

The list should include pollutants relevant to the assessment and management of ambient air quality in accordance with current legislation.

In Spain, official assessment currently includes, among others:

1. SO₂;
2. NO₂ and NOx;
3. PM10;
4. PM2.5;
5. Pb;
6. benzene;
7. CO;
8. As;
9. Cd;
10. Ni;
11. benzo(a)pyrene;
12. O₃.

In addition, for national emissions, pollutants subject to reduction commitments must be considered: SO₂, NOx, NMVOCs, NH₃ and PM₂.₅.

Legislation

Ozone layer

Main current legislation:

1. Regulation (EU) 2024/590, of the European Parliament and of the Council of 7 February 2024 on substances that deplete the ozone layer. It repeals Regulation (EC) 1005/2009.
2. Vienna Convention for the Protection of the Ozone Layer.
3. Montreal Protocol on Substances that Deplete the Ozone Layer, including its amendments currently in force.

Fluorinated greenhouse gases

1. Regulation (EU) 2024/573, of the European Parliament and of the Council of 7 February 2024 on fluorinated greenhouse gases, repealing Regulation (EU) 517/2014.
2. Spanish implementing legislation that remains applicable in areas not superseded by the European Regulation, including Royal Decree 115/2017, within its current scope.

Climate change

1. Paris Agreement, adopted on 12 December 2015 and in force since 4 November 2016.
2. Regulation (EU) 2021/1119, the “European Climate Law”, with its consolidated version in force updated in April 2026.
3. Law 7/2021 of 20 May on climate change and the ecological transition, in its current version.
4. Law 1/2005 of 9 March, regulating the greenhouse gas emissions trading system, in its current version.
5. Royal Decree 203/2024, concerning the free allocation of emission allowances for the 2026–2030 period and the exclusion regime for certain installations.

Ambient air quality

1. Royal Decree 102/2011 of 28 January on the improvement of air quality, in its current version; the latest published update is 25 January 2023.
2. Law 34/2007 of 15 November on air quality and protection of the atmosphere, in its current version, updated on 4 December 2025.
3. Royal Decree 100/2011, updating the catalogue of activities potentially polluting the atmosphere and establishing basic provisions for its application.
4. Royal Decree 815/2013, approving the Industrial Emissions Regulation and developing the legislation on integrated pollution prevention and control.
5. Royal Decree 818/2018, on measures to reduce national emissions of certain atmospheric pollutants, in its current version.
6. Directive (EU) 2016/2284 on the reduction of national emissions of certain atmospheric pollutants, as the European framework for national emission-reduction commitments.
7. Directive (EU) 2024/2881 on ambient air quality and cleaner air for Europe. It is in force and must be transposed by 11 December 2026; Directives 2004/107/EC and 2008/50/EC will be repealed with effect from 12 December 2026.

References

Last updated: August 2026