In the context of environmental science research, ultrafine particulate matter (UFP) is in the spotlight due to its potential impact on human health and the environment, and Airparif, as the Paris Regional Air Quality Observatory, is actively monitoring UFP in the Paris region, and Palas® is pleased to provide the core equipment, Palas® U-SMPS Universal Scanning Mobility Particle Sizer, to facilitate this important research project. Palas® was honored to provide the core equipment, the U-SMPS scanning mobility spectrometer, for this important research project.
Specialized selection of research teams
Airparif brings together a group of specialized researchers, such as Grégory Abbou and Véronique Ghersi, who are well versed in the field of air quality monitoring and research. The team chose the urban background station in the center of Paris (located in the Nelson Mandela Gardens, next to the Forum des Halles shopping mall) as the monitoring site, which reflects the average air pollution in the city.
Location of the Airparif’s supersite in Paris-Les Halles, with a zoom at the neighborhood scale (right panel). (Sources: Carto Positron, Google Earth).
The study period covers a full three-year period from October 15, 2019, to December 31, 2022, during which the major societal changes of the New Crown Pneumonia epidemic were experienced. The study includes recording ultrafine particulate matter concentrations, analyzing their temporal characteristics (covering daily, weekly, monthly, and yearly patterns), exploring their sources through correlation studies between particulate matter and gaseous pollutants, and analysis of the particle size distribution, and comparing the measured concentrations with data from multiple cities around the world.
The key role of Palas® U – SMPS: guaranteeing precise measurements
The Palas® U-SMPS played an important role in this research project. The U-SMPS system was able to accurately differentiate between changes in the concentration of ultrafine particles at different times of the day in Paris, providing a reliable basis for analyzing their sources and formation processes.
Accurate measurement of information on the number level of submicron particles and characterization of specific emission sources and formation processes is key to the study, which requires instruments with high accuracy and a wide range of measurement capabilities to differentiate between particles of different sizes, especially in the ultrafine particle size range (8 – 100 nm) and the wider size interval (8 – 400 nm). Palas® offers U-SMPS systems with bipolar X-ray neutralizers, electrostatic classifiers and condensation nuclei counters covering 108 size classes from 8 to 400 nm to accurately monitor the size distribution of submicron particles and provide precise data for ultrafine particulate measurements. The CNC is calibrated annually and the X-ray source is replaced every 8,000 hours to ensure the accuracy and stability of the instrument.
Averaged 2020-2021-2022 particle number size distributions at the Paris-Les Halles supersite in the 8-400 nm electrical mobility size range.
The key role of Palas® U – SMPS: data Stability Enables Long-Term Research
The three-year-long research cycle requires continuous and stable operation of the instrument to obtain complete and continuous data, and any missing data or instrument malfunction may affect the reliability of the results, especially in the complex urban environment of Paris, where the instrument is exposed to a variety of interfering factors.
Evolution of the daily NUFP average concentrations from October 2019 to December 2022 (in grey). The black curve represents the smooth-trend curve of the data and the shaded areas show the 95th 273 confidence intervals of the fit. Orange zones illustrate the related-COVID 19 lockdown periods in France (I: from March, 17th to May, 11th 2020; II: from October, 30th 274 to November, 15th 2020; III: from April, 3rd to May, 3rd 275 2021)
The U-SMPS system demonstrated excellent stability throughout the study period, with data recorded at 5-minute intervals and stored in a PostgreSQL database, with more than 90% of the data efficiently captured, providing sufficient and continuous data to support the study. It worked stably even in the complex and changing environment of Paris, such as high population density, diverse anthropogenic activities and changing meteorological conditions. The U-SMPS system continued to operate stably during large changes in social activities and environmental conditions during the epidemic, providing critical data for the study of the impact of the epidemic on ultrafine particulate matter concentrations and ensuring the smooth progress of the study.
Averaged daily(a), weekly(b) and monthly(c) NUFP concentrations at the Paris-Les Halles supersite for the years 2020, 2021 and 2022. Shaded areas indicate the 95th 304 confidence intervals of the mean. For readability purposes, graphics are not on the same scale in terms of concentrations.
The key role of Palas® U – SMPS: multi-pollutant synergistic analysis to identify emission sources
Researchers believe that identifying the sources of ultrafine particulate matter emissions is a key and difficult part of the study, and that accurate measurements of multiple pollutant concentrations are needed, as well as correlation analyses between particulate matter and other pollutants (e.g., black carbon, nitrogen dioxide, etc.) to infer the source of the emissions.
Monthly timeseries of wind speed (WS) and wind direction (color scale), boundary layer height (BLH) and normalized ventilation coefficient (VCnorm, shaded areas corresponding to periods with VCnorm > 1) in Paris over the studied period.
By comparing the ultrafine particulate count concentrations measured by the U-SMPS with the black carbon concentrations measured by the Black Carbon Meter, a correlation was found between the two at specific times of the day, which led to the inference that road traffic emissions have a significant impact on ultrafine particulate matter in Paris, and provided strong evidence for identifying the main sources of the emission. The U-SMPS system provides accurate particle number concentration data, which, working together with the Black Carbon meter and Quadrupole Aerosol Mass Spectrometer (QAMS), enables the research team to analyze in depth the correlation between ultrafine particulate matter and multiple pollutants.
Pearson’s correlation coefficient (r) of NUFP with particulate matter, including Black
Carbon (BC), Black Carbon derived from fossil-fuel (BCff) and wood-burning (BCwb)
combustion, organic matter (OM), sulfate (SO4), nitrate (NO3), ammonium (NH4),
Chloride (Chl), PM2.5 and PM10 with a p-value < 0.05.
Palas® instruments play a key role in the monitoring of ultrafine particulate matter in Paris. Its high accuracy and stability of measurements provided the Airparif research team with solid data support, helping to gain a deeper understanding of the characteristics and sources of ultrafine particulate matter in Paris, and providing an important basis for improving the city’s air quality, formulating scientifically sound environmental protection policies, and protecting the public’s health. In the future, Palas® will continue to innovate and provide more advanced instrumentation and technical support for environmental science research.
If you are interested in the technical article “Ultrafine particles monitoring in Paris: from total number concentrations to size distributions measurements.”, please click on Register to download the pdf file.
Product Advantages:
· Particle size distribution from 8 nm to 1,200 nm
· Continuous and fast scanning measurement principle
· High resolution, up to 256 channels (128 channels / 10 times particle size)
· Suitable for concentrations up to 108 particles /cm3
· Connectable to other manufacturers’ DMAs and nanoparticle counters
· Graphic display of measured values
· Intuitive operation with 7-inch touch screen and GUI
· Integrated data logger
· Supports multiple interfaces and remote access
· Low maintenance to reduce your operating costs
· Reliable functionalit
Application Areas:
· Aerosol Research
· Climate Research
· Emission sources looking to locate
· Workplace Measurements
· Filtration Testing
· Exhaust monitoring
Palas® organizes a series of events on various topics to share professional knowledge of aerosol measurement technology. Palas® technical experts and industry scholars from all over the world will give you detailed online explanations. Welcome to register to attend and learn more about the conference as soon as possible!
| Date | Time | Topic | |
| 2025/2/26-27 | 9:30-17:00
9:00-17:30 |
Air Quality Forum 2025 – Brussels, Belgium | Offline-Forum |