Urban air pollution from vehicular emissions remains a pressing public health concern, particularly in Eastern Europe, where data gaps hinder effective mitigation. This study, conducted in the summer of 2024, presents the first detailed analysis of ultrafine particle (UFP) and equivalent black carbon (eBC) emissions from road traffic across Lithuania’s six major cities: Vilnius, Kaunas, Klaipėda, Šiauliai, Panevėžys, and Alytus. We used a custom mobile laboratory to capture real-world emissions, revealing stark spatial disparities. Panevėžys and Vilnius topped eBC levels (10400 ng/m³ and 10200 ng/m³, respectively), driven by aging vehicle fleets and a diesel prevalence of 70 % in Panevėžys, which also recorded the highest UFP concentration (97800 particles/cm³). Emission factors, calculated using an adapted Operational Street Pollution Model (OSPM), identified Vilnius’ light-duty vehicles as leading in particle number emissions (8.90 × 10¹⁴ particles/(km·veh)), likely due to the prevalence of gasoline direct injection engines. At the same time, Panevėžys dominated eBC emissions (150 mg/(km·veh). Heavy-duty vehicles, including buses and trucks, exhibited emission factors up to five times higher than those of their light-duty counterparts, thereby amplifying their impact in urban areas. These findings illuminate emission dynamics in an understudied region, providing policymakers with precise and actionable insights for targeted interventions, such as fleet upgrades or the establishment of low-emission zones. By addressing a critical knowledge gap, this study empowers the scientific community and public health advocates to devise strategies that combat vehicle-related pollution, reduce exposure to harmful pollutants, and foster healthier urban environments across Eastern Europe and beyond.
Studies revealed airports as a prominent source of ultrafine particles (UFP), which can disperse downwind to residential areas, raising health concerns. To expand our understanding of how air traffic-related emissions influence total particle number concentration (PNC) in the airport’s surrounding areas, we conduct long-term assessment of airborne particulate exposure before and after relocation of air traffic from “Otto Lilienthal” Airport (TXL) to Berlin Brandenburg Airport “Willy Brandt” (BER) in Berlin, Germany. Here, we provide insights into the spatial–temporal variability of PNC measured in 16 schools recruited for Berlin-Brandenburg Air Study (BEAR).
The results show that the average PNC in Berlin was 7900 ± 7000 cm−3, consistent with other European cities. The highest median PNC was recorded in spring (6700 cm−3) and the lowest in winter (5100 cm−3). PNC showed a bi-modal increase during morning and evening hours at most measurement sites due to road-traffic emissions. A comparison between measurements at the schools and fixed monitoring sites revealed good agreement at distances up to 5 km. A noticeable decline in this agreement occurred as the distance between measurement sites increased. After TXL was closed, PNC in surrounding areas decreased by 30 %. The opposite trend was not seen after BER was re-opened after the COVID-lock-down, as the air traffic has not reached the full capacity yet. The analysis of particle number size distribution data showed that UFP number fraction exhibit seasonal variations, with higher values in spring and autumn. This can be explained by nucleation events, which notably affected PNC.
The presented findings will play a pivotal role in forthcoming source attribution and epidemiological investigations, offering a holistic understanding of airports’ impact on airborne pollutant levels and their health implications. The study calls for further investigations of air-traffic-related physical–chemical pollutant properties in areas found further away (> 10 km) from airports.
Abstract
Atmospheric new particle formation (NPF) is a naturally occurring phenomenon, during which high concentrations of sub-10 nm particles are created through gas to particle conversion. The NPF is observed in multiple environments around the world. Although it has observable influence onto annual total and ultrafine particle number concentrations (PNC and UFP, respectively), only limited epidemiological studies have investigated whether these particles are associated with adverse health effects. One plausible reason for this limitation may be related to the absence of NPF identifiers available in UFP and PNC data sets. Until recently, the regional NPF events were usually identified manually from particle number size distribution contour plots. Identification of NPF across multi-annual and multiple station data sets remained a tedious task. In this work, we introduce a regional NPF identifier, created using an automated, machine learning based algorithm. The regional NPF event tag was created for 65 measurement sites globally, covering the period from 1996 to 2023. The discussed data set can be used in future studies related to regional NPF.
In this paper, we investigate physico-chemical properties of particulate matter (PM) at an urban mixed site (UB) and two roadside (RS) sites during the 2015 Metro Manila Aerosol Characterization Experiment (MACE). Aerosol particle number size distributions (0.01–10 μm diameter) were measured using a combination of a mobility particle size spectrometer and aerodynamic particle size spectrometers. PM2.5 filter samples were analyzed for total mass, organic carbon (OC), elemental carbon (EC), water-soluble inorganic ions, and elemental species. Mass closure between the gravimetric mass, chemical composition, and mass concentration derived from the number size distribution was performed. We found that the bulk PM2.5 mass was dominated by carbonaceous materials, followed by secondary inorganic aerosols and crustal matter at all sites. The average OC/EC ratios at the RS sites (0.16–1.15) suggest that a major fraction of the aerosol mass at these sites derives from traffic sources, while the OC/EC ratio at the UB site (2.92) is indicative of a more aged aerosol, consistent with greater contribution from secondary organic carbon (SOC) formation. The ultrafine particles (UFPs, diameter < 100 nm) dominated (89–95%) the total particle number concentration at the three sites, highlighting the importance of such measurements in this region. However, UFPs have low mass contribution to PM2.5 (7–18%), while particles in the accumulation mode (diameter 100–1000 nm) accounted for most of the number-derived PM2.5 mass concentration (61–67%). On average, strong agreement between the chemically-derived mass and the gravimetric mass was found (slope = 1.02; r2 = 0.94). The number-derived mass concentration correlated well with the gravimetric PM2.5 mass (slope = 1.06; r2 = 0.81). These results highlight the need for more comprehensive PM characterization, particularly focusing on size-resolved chemical composition and particle number size distributions. The mass closure approach presented in this work provides a framework for a conversion between number size distributions and PM2.5 mass concentration in real time in an environment with similar characteristics.
