We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Reply on RC2
AI summary Read the abstract
Researchers developed a sodium-thiosulfate ozone denuder for ultrafine particle sampling and demonstrated that without ozone removal, PAH concentrations in collected particles were underestimated by 15–46% and 6PPD antioxidant from tire wear was artifactually oxidized to the more toxic 6PPD-quinone, highlighting a critical sampling artifact with implications for roadway pollution studies.
Abstract. Ozone (O₃) remaining in sampling air can artefactually alter the chemical composition of collected ultrafine particles (UFP), biasing quantitative analysis of the chemical composition. In this study, we developed and evaluated a sodium-thiosulfate O₃ denuder (TSOD) specifically tailored for UFP sampling and assessed its O₃ scrubbing efficiency, particle losses, and chemical selectivity. In laboratory tests under controlled relative humidity and inlet O₃ levels up to 200 ppbV, the outlet concentration remained consistently between 0 and 0.3 ppbV, demonstrating the O₃ removal efficiency of the TSOD. During an urban field deployment over 7 days O₃ downstream of the TSOD consistently remained at 0 ppbV while ambient O₃ varied between 0 and 65 ppbV. Moreover, for particles with mobility diameters ranging from 10 to 1000 nm, we did not observe any significant losses in particle number concentrations. Using a parallel two-channel UFP sampler (with vs. without upstream TSOD), we quantified O₃-driven sampling artefacts in UFP mass focussing on three types of organic markers. (1) Firstly, we targeted polycyclic aromatic hydrocarbons (PAH), particularly chrysene (Chry), benz[a]anthracene (BaA), benzo[a]pyrene (BaP), indeno[1,2,3-cd]pyrene (IcdP), benzo[k]fluoranthene (BkF), and benzo[b]fluoranthene (BbF). Without upstream O₃ removal, the individual concentration of the PAH were 15–46 % lower. (2) Secondly, for the tire and road wear marker, the antioxidant N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) and its oxidation product 6PPD-quinone (6PPDq), we observed in-situ ozonation of 6PPD to 6PPDq with transformation yields of about 13 to 20 %. (3) In contrast, biogenic organic acids (bOAs) did not show differences when sampled with or without O₃, as their O₃ reactivity is much lower than the one of the PAH. Moreover, this test indicated that the TSOD did not perturb the gas–particle partitioning of these semi-volatile species. Our results demonstrate that the TSOD (i) efficiently scrubs atmospheric O₃ at relevant mixing ratios, (ii) does not introduce measurable particle losses across 10–1000 nm, and (iii) preserves semi-volatile partitioning.
More Papers Like This
Reply on RC1
AI summary Read the abstract
Researchers designed and validated a sodium-thiosulfate ozone denuder for ultrafine particle sampling, showing it removes atmospheric ozone without causing measurable particle losses and prevents ozone-driven artifacts that would otherwise bias measurements of PAHs and tire wear markers like 6PPD-quinone by up to 46%.
Sodium thiosulfate-coated ceramic denuders for ozone removal in ultrafine particle sampling
AI summary Read the abstract
When scientists measure air pollution particles, ozone in the air sample can chemically react with pollutants before they're even measured, throwing off the results. This study created a filter that removes ozone during air sampling without disturbing the tiny particles being studied, and found that without it, harmful chemicals like PAHs (found in vehicle exhaust and smoke) were undercounted by 15-46%, while a tire-wear chemical linked to health concerns actually got converted into a different compound. This matters because accurate air quality measurements help researchers and regulators better understand what pollutants people are really breathing in, especially from traffic-related sources.
Characteristics of Real-world Non-exhaust Particulates from Vehicles
AI summary Read the abstract
Researchers characterized non-exhaust particulate emissions from vehicle tire and road wear, collecting atmospheric PM samples with a high-volume quartz filter sampler and using pyrolysis-GC/MS to analyze tire rubber markers including polycyclic aromatic hydrocarbons and heavy metals, quantifying the contribution of tire-brake-road wear particles to urban air pollution.
Organic Markers of Tire and Road Wear Particles in Sediments and Soils: Transformation Products of Major Antiozonants as Promising Candidates.
AI summary Read the abstract
Researchers identified organic chemical markers that can trace tire and road wear particles (TRWPs) in soils and sediments. They found that benzothiazole derivatives and transformation products of tire rubber chemicals were detectable in environmental samples and could serve as quantitative indicators of TRWP contamination. This provides scientists with better tools for tracking traffic-related pollution in the environment.
Disentangling Traffic Emissions in Road Airborne Particles across China: 6PPD-Q as a Molecular Marker for Tire Wear Particles
AI summary Read the abstract
Scientists studying air pollution near roads in China found that a chemical called 6PPD-Q, which comes from tire rubber, can be used as a reliable marker to track tiny particles worn off car tires as they float in the air we breathe. Surprisingly, the study found that tire wear, brake dust, and road dust kicked up by traffic together make up more than 75% of traffic-related air pollution—far outweighing pollution from tailpipe exhaust. This matters because it suggests that efforts to clean up air quality have focused too heavily on exhaust fumes while largely ignoring these other sources, which may carry harmful ch
Research digests by email
When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.