Air quality around ports and airports

Introduction

Air pollution is Europe’s largest environmental health risk, with multiple impacts on human health (EEA, 2024b). Fine particulate matter (PM_2.5) and nitrogen dioxide (NO₂) are two of the main air pollutants in this respect.

In the EU-27, transport was the largest emitter of nitrogen oxides (NO_x) in 2022 with a share of 56.5%. Transport also produced 29.3% of PM₁₀ and PM_2.5 in the EU-27 in the same year (EEA, 2024c).

NOₓ emissions from maritime transport in the EU-27 increased by 10% between 2015 and 2023. This sector now accounts for 39% of all NOₓ emissions from EU-27 transport (EEA and EMSA, 2025). Its contribution to overall particulate matter (PM_2.5) in transport emissions has also remained high, peaking at 43% in 2019 and maintaining similar levels in 2022. The relative contribution of shipping to air pollution in Europe is rising. Shipping emissions are projected to surpass road traffic as the leading source of transport-related air pollution and associated health impacts in coastal cities by 2030 (EEA and EMSA, 2025).

Aviation (both domestic and international) is an important NO_x emitter and accounts for 14% of all transport emissions in 2022 (EEA, 2024c). Emissions from this sector increased for most pollutants between 1990 and 2022 in the EU-27, including NO_x, sulphur oxides (SO_x), ammonia (NH₃) and particulate matter (PM₁₀ and PM_2.5). Emission increases ranged between 47% and 117% since 1990, depending on the pollutant (EEA, 2024a). Levels fell for methane (CH₄), carbon monoxide (CO) and non-methane volatile organic compounds (NMVOC).

Monitoring air quality in and around ports, airports and nearby cities will become more important in the coming decades. This will help assess the role of emissions from shipping and aviation as well as all related activities including road traffic, non-road machinery, bulk unloading and industrial installations.

This briefing explores air quality monitoring around key European ports and airports, compares NO₂ and PM_2.5 levels with nearby regions, analyses pollution trends and assesses the possible impact these sources have on air quality levels.

Air quality data analysis around ports

This report analysed the 22 largest and most significant ports across 10 European countries, covering the main European ports for containers, passengers and freight (Figure 1). The study was performed in collaboration with the European Topic Centre on Human Health and Environment (ETC HE) for the European Maritime Transport Environmental Report (EEA and EMSA, 2025).

Review of air quality monitoring stations around ports

Multiple emission sources influence port areas, including, national and international shipping, road and non-road traffic, industry and energy consumption. The ETC HE assessed air quality sampling points (SPOs) around ports across all wind directions (Pozzoli, L. et al., 2024). SPO numbers vary significantly, reflecting differences in monitoring intensity and network design. This report includes only SPOs reported to the EEA.

For NO₂, Amsterdam and Antwerpen have the highest SPO numbers within 5km and 10km from ports, according to 2023 data, followed by Algeciras, Barcelona, Stockholm, Hamburg and Napoli (Pozzoli, L. et al., 2025b). Some cities, including Reggio Calabria and Gioia Tauro have no SPOs within 5km of the port.

For PM_2.5, Antwerpen has the most SPOs at 16 within 10km and 26 within 20km. Amsterdam, Barcelona, Napoli, Algeciras, Santa Cruz de Tenerife and Stockholm all have over 10 SPOs within 20km. In contrast, four ports lack SPOs within 5km, in Algeciras, Gioia Tauro, Palma de Mallorca and Reggio Calabria.

However, few SPOs are located downwind within the relevant predominant wind direction of the port as recommended by the Ambient Air Quality Directive (EU, 2024). Based on the analysis performed for year 2021 (Pozzoli, L. et al., 2024) only five ports (Algeciras, Antwerpen, Genova, Marseille and Napoli) have at least one NO₂ SPO downwind of the port more than 25% of the time. Some ports are well monitored. Amsterdam and Antwerpen have NO₂ SPOs in seven of the eight wind sectors around the port, covering 79% and 91% of the total wind frequency, respectively. However, the total wind frequency is above 50% in only eight of the 22 analysed ports. This means that half of the time, the direct impact of the port on NO₂ levels is not being recorded.

An analysis of pollutant levels from available SPOs under downwind conditions revealed substantial increases in NO₂ concentrations: over 100% in Napoli, 86% in Hamburg, 77% in Algeciras and 75% in Antwerpen. These trends varied by wind sector and may also reflect contributions from other urban pollution sources.

Air quality levels around ports based on air quality maps

Comparing pollutant concentrations between ports and surrounding regions is difficult using monitoring data alone, due to the limited number of air quality SPOs near some port areas. To address this limitation and ensure consistency, EEA air quality maps were used to estimate NO₂ and PM_2.5 concentrations within port areas and their surrounding regions (Pozzoli, L. et al., 2025b). EEA air quality maps are provided at 1km resolution, and combine model outputs with air quality observations and land cover data (Horálek, J. et al., 2025). Pollutant concentrations for urban areas estimated in the maps are more representative of urban background levels. Comparisons between ports and surrounding regions likely underestimate the true difference in air quality levels.

Figure 1 shows NO₂ and PM_2.5 concentrations in port areas (located within 1km from the port area polygon) and surrounding regions (area covering 0.5 degrees longitude and latitude from the centre of the port area) for each of the analysed ports. Annual mean NO₂ concentrations were higher in all studied ports compared to their surrounding regions in 2023. Variations in concentration ranged from 1.4µg/m³ in Malta Freeport to over 10µg/m³ in ports including Algeciras, Marseille, Napoli and Piraeus. NO₂ levels were over double those in surrounding regions in half of the studied ports. Algeciras showed concentrations four times higher. NO₂ concentrations in Piraeus and Napoli ports were above 20µg/m³, the revised annual limit value for the protection of human health set under the Ambient Air Quality Directive (EU, 2024), to be attained by 1 January 2030. Marseille fell just below this threshold, with an NO₂ concentration of 19.6µg/m³.

Similarly, PM_2.5 concentrations were generally higher in port areas compared to surrounding regions, though differences were less pronounced. The largest difference – over 5µg/m³ or 42% – was found in Piraeus. Other ports showed comparative increases ranging from 3% to 31%. Despite the more modest differences, 13 out of 22 ports had PM_2.5 concentrations above 10µg/m³, the revised annual limit value under the Ambient Air Quality Directive (EU, 2024). Additionally, four regions – Piraeus, Napoli, Barcelona and Malta Freeport – were also above this value.

Figure 1. Map of analysed ports showing NO₂ and PM_2.5 concentrations in port areas and surrounding regions

This analysis is based on annual mean values and does not account for short-term exposure metrics such as hourly or daily concentrations. Additional information can be found in the ETC HE report (Pozzoli, L. et al., 2024)

Trends in pollutant concentrations in ports and nearby cities

Long-term NO₂ level trends were analysed at the identified SPOs in European port areas and nearby cities. Average NO₂ concentrations in port areas or within 1km vicinity of a port decreased by about 45% between 2005 and 2023, similar to the reduction in nearby cities. However, due to the limited number of SPOs identified in port areas, this cannot be considered a general conclusion of trends in all cities near ports. For PM_2.5, the number of SPOs with available trend data is considerably lower than for NO₂, making it difficult to present generalised results.

Antwerpen stands out for its extensive monitoring network (Figure 2). A visible gradient shows falling NO₂ concentration levels from 2005 to 2023. Smaller reductions from 29% to 37% were observed in the four SPOs inside or very near to the port in the north-west, with the largest reductions within the city (from 44% to 58%). This is likely due to larger emission reductions from other sources, such as road traffic.

Figure 2. Trends in NO₂ concentrations at monitoring stations in the port and city of Antwerpen

Air quality data analysis around airports

A total of 23 airports across 17 countries were analysed (Figure 3). Airport selection relied on multiple criteria including the number of passenger (EUROSTAT, 2023b) and freight flights (EUROSTAT, 2023a), the population of surrounding regions, the presence of air quality monitoring stations for NO₂ and PM_2.5 and the availability of studies on ultrafine particles (UFP).

Review of air quality monitoring stations around airports

The ETC HE report presents the number of available SPOs within 10km for NO₂ and 20km for PM_2.5 (Pozzoli, L. et al., 2025a). It highlights SPOs at or near airports (within 1km), their types, average distance and wind sector distribution. Analysis of total wind frequency revealed how often SPOs can measure air coming from the airports. This report includes only SPOs reported to the EEA.

All included airports have at least one NO₂ SPO within a 10km distance, with the majority of SPOs classified as background stations. Three airports, Brussels (BRU), Dublin (DUB) and Madrid (MAD) have one NO₂ SPO within the airport area. Eight of the 23 airports have at least one SPO situated within 1km of the airport perimeter. Wind frequency coverage for NO₂ SPOs (the proportion of time that wind blows the pollutant towards the existing SPOs) varies significantly across locations, ranging from 12% in Helsinki (HEL) to 69% in Lisbon (LIS).

For PM_2.5, all the airports except Vilnius (VNO) have at least one SPO within a 20km radius. Only four airports, Brussels (BRU), Dublin (DUB), Dusseldorf (DUS) and Rome (FCO), have an SPO within 1km. Wind frequency coverage for PM_2.5 SPOs varies widely, ranging from 10% in Athens (ATH) to 87% in Warsaw (WAW). In total, 13 airports have less than 50% wind frequency coverage. This means SPOs do not capture the potential impact of airport emissions for over half of the time.

Around several airports, hourly NO₂ concentrations in nearby SPOs were significantly higher when wind blew from the direction of the airport. The most striking example was Amsterdam (AMS), which showed a rise of 113% (26.6µg/m³ mean NO₂ concentration compared to 12.5µg/m³ when wind blew from all other directions). Other notable examples include Rome (FCO), with a 90% increase (17.8µg/m³ compared to 9.4µg/m³); Lisbon (LIS), with an 88% increase (33.7µg/m³ compared to 17.9µg/m³) and Madrid (MAD), with an 83% increase (33µg/m³ compared 18µg/m³). Wind frequency from the airport in this analysis ranged from 12% to 32%. This suggests that even with moderate wind occurrence, airport-related emissions can affect NO₂ levels. This is not a precise estimate, however, as the analysis does not isolate airport emissions from other regional pollution sources.

For PM_2.5 the downwind impact on the available SPOs was not as evident, with a maximum increase of around 40% in Paris (CDG) and Madrid (MAD). Again, other sources could be contributing to these levels.

Air quality levels around airports based on air quality maps

The same methodology to assess air quality around ports was used for airports based on 2023 data. EEA air quality maps provided concentrations of NO₂ and PM_2.5 within airports and their surrounding regions(Pozzoli, L. et al., 2025a).

Annual mean NO₂ concentrations in 2023 were higher in all studied airports compared to surrounding regions, except in Rome (FCO), where concentrations were the same. In many cases this could be comparable to levels found in the high-density residential zones, due to traffic. Differences between NO₂ concentrations in airports and surrounding regions ranged from 1.3µg/m³ in Athens (ATH) to over 10µg/m³ in Madrid (MAD) and Lisbon (LIS). Airport NO₂ levels in Vilnius (VNO) and Madrid (MAD) were double those in surrounding areas. Lisbon (LIS) levels were three times higher. NO₂ concentration in Milan (LIN) was above 20µg/m³, the revised annual limit value for the protection of human health set under the Ambient Air Quality Directive (EU, 2024) to be attained by 1 January 2030.

PM_2.5 concentrations in airports were in some cases similar to those of surrounding regions, for example in Copenhagen (CPH), Rome (FCO), Amsterdam (AMS), Athens (ATH), and Berlin (BER). Levels at airports were higher for all other studied locations. Differences for PM_2.5 are less pronounced than those for NO₂, ranging from a 5% to a 39% increase in the airport areas compared to the surrounding regions. The greatest differences— between 2µg/m³ and 3µg/m³ — were found in Bucharest (OTP), Lisbon (LIS), Milan (LIN), Madrid (MAD) and Warsaw (WAW). Nevertheless, six out of 23 airports had PM_2.5 concentrations above 10µg/m³ and four were just below this level (the revised 2030 EU annual limit value) (EU, 2024). Additionally, levels in the surrounding regions of five airports, Milan, Bucharest, Warsaw, Athens and Rome, were also above this value.

Figure 3. Map of analysed airports showing NO₂ and PM_2.5 concentrations in airport areas and surrounding regions

Trends in pollutant concentrations in airports and nearby cities

NO₂ levels fell around 45% on average between 2005 to 2023, both at SPOs within 5km from airports and those further away. The analysis of other SPOs types (traffic and industrial) and of PM_2.5 was inconclusive due to the limited number of SPOs (Pozzoli, L. et al., 2025a).

Ultrafine particles around airports

UFPs, defined as airborne particles with a diameter ≤100nm, are measured by total particle number concentration (PNC). UFPs are generated through various natural and anthropogenic combustion processes, including forest fires and volcanoes, traffic, aircraft operations, power plants and domestic heating. They also form in the atmosphere via photochemical reactions from gaseous precursors. Due to their dynamic nature, UFP concentrations show high spatial and temporal variability.

UFPs pose distinct health risks compared to larger particles (PM₁₀, PM_2.5), as they can penetrate deep into the lungs, reach the brain and potentially enter the bloodstream. Evidence suggests adverse short-term associations with inflammatory and cardiovascular changes, which may be at least partly independent of other pollutants. For the other studied health outcomes, evidence on independent health effects of UFPs remains inconclusive or insufficient (Ohlwein et al., 2019)(Bergmann et al., 2025).

The revised Ambient Air Quality directive now mandates UFP measurement where high concentrations are expected and on supersites (new monitoring stations that combines multiple SPOs to gather long-term data on several pollutants). This aligns with the WHO recognition of UFPs as a pollutant of emerging concern, despite the absence of formal guideline values. High PNC is considered to be above 10,000 particles/cm³ over 24 hours or 20,000 particles/cm³ on an hourly basis (WHO, 2021).

The EU’s new monitoring requirements will help strengthen the evidence base and support future policy development on UFP exposure and health protection.

There is increasing interest in measuring UFP around airports as a major source of emissions. Several airports included in this study have measured or are currently measuring UFP. These include Amsterdam (AMS), Berlin (BER), Brussels (BRU), Copenhagen (CPH), Frankfurt (FRA), Helsinki (HEL), Paris (CDG), Vienna (VIE) and Zurich (ZRH).

UFP concentrations vary significantly across these airports. However, as different lower and upper cut offs were used, the results are non‑comparable as the size range of particles also varies. Several common trends still emerge.

Measurements taken within or very close to airport areas (up to 1km) consistently show the highest PNC. This often exceeds 20,000 particles/cm³, as seen in Copenhagen (CPH), with an annual average up to 27,000 particles/cm³ downwind of the airport; Zurich (ZRH), with an annual average of 24,000 particles/cm³, and Paris (CDG), with an average of 23,000 particles/cm³ over four months. In contrast, stations located further away (5 to 10km) generally report lower concentrations, often below 10,000 particles/cm³. This suggests a rapid decline in UFP levels with distance from the source. Additionally, these findings reinforce the need for standardised monitoring protocols and strategic measurement station placement to accurately assess population exposure.

Wind direction also plays a notable role in UFP dispersion, with the impact of airport activities sometimes detected at longer distances. For example, in Amsterdam, the airport potentially contributes up to 5% of total PNC and 16% of 10-20nm particles 8km downwind of the airport (Hofman et al., 2016). The contribution of Berlin Airport to the total UFP concentration was significantly greater than that of motor vehicle traffic, extending up to approximately 7km downwind of the terminal (Gerling and Weber, 2023). These results were also confirmed by modelling (Pozzoli, L. et al., 2025a).

Conclusions

The availability of sampling points (SPOs) in and around port and airport areas remains limited. This makes it difficult to reliably assess differences in air pollutant concentrations between these transport hubs and nearby regions using monitoring data alone.

However, an analysis of EEA air quality maps reveals that ports and airports across Europe consistently exhibit elevated levels of NO₂ and to a lesser extent, PM_2.5, compared to surrounding regions. Interpolated air quality data for 2023 show that several locations had levels above the revised EU annual limit values for 2030, particularly for NO₂. Ports such as Algeciras, Marseille and Napoli, and airports including Lisbon and Madrid, showed significantly higher NO₂ concentrations than surrounding regions.

The analysis also highlights that the design and placement of air quality monitoring stations is critical. SPOs located downwind from ports and airports consistently recorded higher NO₂ levels, sometimes over double compared to SPOs located in other wind directions. Despite this, the current location and overall number of SPOs remain insufficient for many ports and airports. This underscores a need to improve network design and spatial coverage to better capture the impact of emissions from ports and airports. Given the limited and uneven coverage of SPOs, a harmonised methodology for measuring and reporting emissions and air quality data in port areas should be assessed further. A more complete picture of life cycle emissions from each vessel is needed, building on the European Maritime Transport Environmental Report (EMTER) (EEA and EMSA, 2025). Future work could identify methods suited to complex port environments to improve air pollutant emission’s data consistency and reliability across Europe.

These findings suggest ports and airports areas can be substantial sources of air pollution, especially for NO₂. While the impact on PM_2.5 appears more complex and less directly attributable to port or airport emissions alone, levels in surrounding regions (which in some cases were above the revised 2030 annual limit value) indicate they may be relevant sources in the broader urban air quality context.

As such, some of the studied ports and airports may require enhanced monitoring networks as they could be considered air quality hotspots. Furthermore, air quality zones above the forthcoming limits must develop and implement air quality roadmaps, including measures to reduce pollution and to achieve compliance by 2030.

UFPs, although not yet regulated by EU air quality standards, are emerging as pollutants of concern due to their potential health impacts. Measurements near several major airports show UFP concentrations well above the WHO’s threshold for high exposure, especially within 1km of airport operations. These findings suggest that aviation could significantly contribute to local UFP levels. The revised Ambient Air Quality Directive now mandates UFP monitoring in high concentration areas, which will help build the evidence base for future policy development and public health protection.