Air pollution and companies: sources, regulation and measurement

Air pollution is the presence in the air of substances, as gases or particles, in concentrations that can harm human health, ecosystems and materials. For companies it is both an impact they generate and an increasingly regulated field, so it is worth understanding which pollutants their activities emit, which legal obligations apply and how to measure and reduce those emissions.

Unlike greenhouse gases, which warm the planet globally, the classic air pollutants (particles, nitrogen oxides, sulphur dioxide, ozone) act mostly at local and regional scale, on the quality of the air we breathe. Both problems share, however, many sources: the burning of fossil fuels in transport, industry and energy.

In 2024 the European Union adopted a new air quality directive that tightens the legal limits, and in Spain cities are moving forward with low emission zones. This article summarises the landscape for a company that wants to comply and manage its air footprint well.

Main air pollutants

The pollutants with the greatest impact on health and the environment, and which regulation monitors, are:

• Suspended particles (PM10 and PM2.5): small solid and liquid fragments; the finest penetrate lungs and blood.
• Nitrogen oxides (NOx): formed in high-temperature combustion, especially in diesel engines; they contribute to smog and ground-level ozone.
• Sulphur dioxide (SO2): comes from burning sulphur-bearing fuels; causes acid rain and respiratory problems.
• Ground-level ozone (O3): a secondary pollutant formed by the reaction of NOx and volatile organic compounds under sunlight.
• Volatile organic compounds (VOCs): emitted from solvents, paints, refining and fuel storage.
• Ammonia (NH3) and heavy metals: the former strongly linked to farming and livestock; the latter to certain industrial processes.

Corporate sources of air pollution

An organisation's emissions fall into three broad blocks:

Industry and processes

Combustion in boilers and furnaces, manufacturing processes, handling of dusty materials and the use of solvents generate particles, SO2, NOx and VOCs. Large industrial installations are subject to integrated environmental permits and specific emission limit values.

Combustion and energy

Burning natural gas, diesel or coal to produce heat or electricity is a direct source of pollutants. Improving energy efficiency and electrifying processes with renewable energy reduces both pollutants and carbon emissions at the same time.

Transport and logistics

Vehicle fleets and goods delivery emit NOx and particles. Committing to sustainable transport, renewing the fleet and optimising routes is one of the most effective levers, especially for companies with urban activity.

Regulatory framework: European Union and Spain

The current European reference is Directive (EU) 2024/2881 on ambient air quality and cleaner air for Europe, adopted on 23 October 2024. It recasts the previous directives, lowers the limit values for pollutants such as PM2.5 and NO2 with a 2030 horizon to bring them closer to the WHO recommendations, and strengthens monitoring, public information and the right to compensation. Member States must transpose it by 11 December 2026 at the latest.

In Spain, the air quality framework is set by Royal Decree 102/2011 on improving air quality, amended by Royal Decree 34/2023, which transposed the earlier European directives and will need to be adapted to the 2024 one. It regulates quality objectives for particles, NO2, SO2, ozone, benzene, carbon monoxide and metals, and requires authorities to monitor and, when thresholds are exceeded, to adopt improvement plans.

Alongside this air quality framework sit climate instruments such as the emissions trading market (ETS), which puts a price on the carbon of large industrial and energy installations, and Law 7/2021 on climate change and energy transition, which drives low emission zones in cities. Although they pursue different goals (climate and air), their effects reinforce each other.

Low emission zones and climate

Low emission zones (LEZ) are urban areas where access is restricted for the most polluting vehicles according to their environmental label. Law 7/2021 requires municipalities with more than 50,000 inhabitants to establish them, and its development through Royal Decree 1052/2022 sets common requirements. For companies with urban delivery or fleets, LEZ determine which vehicles can circulate and push towards electrification.

The link with climate is direct: almost every measure that reduces air pollutants (less fossil combustion, more efficiency, more electrification) also reduces the emissions that cause climate change. Measuring both well makes it possible to prioritise investments that deliver a double benefit.

How to measure and reduce emissions

Measuring is the first step. Depending on size and sector, a company can combine direct measurements at emission points (stacks, ducts) with estimates based on consumption and emission factors. For the activity as a whole, calculating the environmental impact and the carbon footprint helps locate the sources that weigh most.

Some common reduction measures:

1. Replace fossil fuels with renewable electricity and improve the performance of boilers and furnaces.
2. Install gas cleaning and particle capture systems in industrial processes.
3. Renew the fleet, adopt low- or zero-emission vehicles and plan routes to cut mileage.
4. Reformulate products and processes to lower solvent and VOC content.
5. Draw up staff mobility plans that reduce car commuting.

The mobility framework is evolving fast. To understand how it affects transport, you can read the article on how the Sustainable Mobility Law is changing the transport sector.

Frequently asked questions

What is the difference between air pollution and greenhouse gases?

Air pollution covers substances that harm health and the environment at local and regional scale, such as particles, NOx or SO2. Greenhouse gases, such as CO2 or methane, warm the planet globally. They share many sources, especially the burning of fossil fuels, but are regulated under different frameworks.

Which air quality rules must companies comply with in Spain?

The general framework is Royal Decree 102/2011, which sets air quality objectives, together with the new Directive (EU) 2024/2881, which must be transposed before 11 December 2026. Large industrial installations also have their own environmental permit and emission limit values.

Does measuring the carbon footprint help with air pollution?

Yes. Many carbon sources are also sources of air pollutants, so measuring and reducing the carbon footprint usually reduces, in parallel, the emissions that degrade air quality.

Manage your air emissions with Manglai

Reducing your company's air pollution starts with measuring. With Manglai you can calculate the carbon footprint of your operations, identify the combustion, energy and transport sources that pollute the most and plan reductions with reliable data, aligning air regulation compliance with your climate goals.