
Hartmut HerrmannLeibniz Institute for Tropospheric Research (TROPOS) · Atmospheric Chemistry Department (ACD)
Hartmut Herrmann
Prof. Dr.
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1,281
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Introduction
Our research intends to understand the tropospheric multiphase system. Model development is based on experimental work in the laboratory and in the field. Lab work utilises state-of-the-art physical and analytical chemistry methods to study gas phase, aqueous phase, organic phase, surface and, alltogether, multiphase phenomena. Field work aims to understand chemical processing and composition of tropospheric particles, clouds, fog and rain in the complex interplay of all compartments involved.
Additional affiliations
January 2018 - present
July 1997 - October 2017
April 2015 - present
Publications
Publications (1,281)
Hygroscopicity strongly influences aerosol properties and multiphase chemistry, which is essential in several atmospheric processes. Although CCN (cloud condensation nuclei) properties are commonly measured, sub-saturated hygroscopicity measurements remain rare. During the ACROSS campaign (Atmospheric ChemistRy Of the Suburban foreSt, conducted in...
Submicron particles (PM1) play a critical role in air quality, climate, and human health. Long-term monitoring is essential to identify changes in atmospheric composition driven by natural or anthropogenic emissions and processes. This study presents ten years of continuous measurements (Sept. 2012–Aug. 2022) at the TROPOS Melpitz research station...
Reactive bromine species play important roles in atmospheric chemistry and influence the abundance of climate‐ and air quality‐relevant trace gases. While extensive studies have focused on bromine chemistry in polar regions, the bromine species in extrapolar regions, particularly regarding pollution‐related bromine recycling, have received less att...
Oxidation of emitted anthropogenic and biogenic volatile organic compounds (VOCs) and subsequent chemical reactions reduce the volatility of the products formed leading to secondary organic aerosol (SOA) formation. Despite the huge diversity of individual SOA compounds, SOA modelling is often simplified and estimated at the initial oxidation step n...
In the Central Asian region, susceptibility to dust storms and escalating anthropogenic emissions poses challenges for air quality as well as environmental health. This study explores the temporal and seasonal dynamics of oxygenated polycyclic aromatic hydrocarbons (OPAHs) and aliphatic ketones in particulate matter during the Central Asian Dust Ex...
Hygroscopicity strongly influences aerosol properties and multiphase chemistry, which is essential in several atmospheric processes. Although CCN (cloud condensation nuclei) properties are commonly measured, sub-saturated hygroscopicity measurements remain rare. During the ACROSS campaign (Atmospheric ChemistRy Of the Suburban foreSt, in Paris, Sum...
The oceanic emission of dimethyl sulfide (DMS) plays a vital role in the Earth's climate system and constitutes a substantial source of uncertainty when evaluating aerosol radiative forcing. Currently, the widely used monthly climatology of sea surface DMS concentration falls short of meeting the requirement for accurately simulating DMS-derived ae...
Acetylperoxyl radical (CH3C(O)OO●) is among highly reactive organic radicals which are known to play crucial roles in atmospheric chemistry, aqueous chemistry and, most recently, peracetic acid (PAA)-based advanced oxidation processes. However, fundamental knowledge for its reactivity is scarce and severely hampers the understanding of relevant env...
This paper presents the findings from a collaborative interlaboratory comparison exercise designed to assess oxidative potential (OP) measurements conducted by 20 laboratories worldwide. This study represents an innovative effort as the first exercise specifically aimed at harmonising this type of OP assay, setting a new benchmark in the field. Ove...
Context:
Carbonyl compounds, especially aldehydes, emitted to the atmosphere, may suffer hydration in aerosols or water droplets in clouds. At the same time, they can react with hydroxyl radicals which may add or abstract hydrogen atoms from these species. The interplay between hydration and hydrogen abstraction is studied using density functional...
Recently, nitrate (NO 3 – ) levels in winter pollution in eastern China have been increasing yearly and have become the main component of PM 2.5 . The factors contributing to this rise in surface NO 3 – concentrations remain unclear, complicating the development of targeted pollution control measures. This study utilizes observational data from Sha...
Sulfurous acid (H2SO3) is known to be thermodynamically instable decomposing into SO2 and H2O. All attempts to detect this elusive acid in solution failed up to now. Reported H2SO3 formation from an experiment carried out in a mass spectrometer as well as results from theoretical calculations, however, indicated a possible kinetic stability in the...
Soil is central to the complex interplay among biodiversity, climate, and society. This paper examines the interconnectedness of soil biodiversity, climate change, and societal impacts, emphasizing the urgent need for integrated solutions. Human‐induced biodiversity loss and climate change intensify environmental degradation, threatening human well...
Climate extremes are on the rise. Impacts of extreme climate and weather events on ecosystem services and ultimately human well‐being can be partially attenuated by the organismic, structural, and functional diversity of the affected land surface. However, the ongoing transformation of terrestrial ecosystems through intensified exploitation and man...
Monomethylamine (MMA), dimethylamine (DMA), and trimethylamine (TMA) are important compounds for atmospheric key processes, e.g., new particle formation (NPF). A description of their multiphase chemical processing within atmospheric models is incomplete, but mandatory to describe their atmospheric budgets. In this study, a detailed multiphase chemi...
Context: Carbonyl compounds, especially aldehydes, emitted to the atmosphere, may suffer hydration in aerosols or water droplets in clouds. At the same time, they can react with hydroxyl radicals which may add or abstract hydrogen atoms from these species. The interplay between hydration and hydrogen abstraction is studied using density functional...
Sulfurous acid (H2SO3) is known to be thermodynamically instable decomposing into SO2 and H2O. All attempts to detect this elusive acid in solution failed up to now. Reported H2SO3 formation from an experiment carried out in a mass spectrometer as well as results from theoretical calculations, however, indicated a possible kinetic stability in the...
The Aerosol, Clouds and Trace Gases Research Infrastructure (ACTRIS) officially became the 33 rd European Research Infrastructure Consortium (ERIC) on April 25, 2023 with the support of 17 founding member and observer countries. As a pan-European legal organization, ACTRIS ERIC will coordinate the provision of data and data products on short-lived...
Particulate matter (PM) is an important component in the atmosphere, affecting air quality, health, radiation balance, and global climate. To assess regional air quality in the city of Fez, an intensive field campaign was carried out in the autumn of 2019 in the Middle Atlas region of Morocco. Aerosol sampling was performed simultaneously at two ur...
In this work, an optimized protocol to generate an expansion-type liquid clouds with and without UV-visible light irradiation conditions for simulation chamber studies is presented. Sensitivity of the process to key parameters such as initial relative humidities, temperature inhomogeneities, droplets lifetime or seed particle number is illustrated....
Recent years have seen an increase in the use of wood for energy production of over 30 %, and this trend is expected to continue due to the current energy crisis and geopolitical instability. At present, residential wood burning (RWB) is one of the most important sources of organic aerosols (OAs) and black carbon (BC), posing a significant risk to...
Risk assessment of pesticide impacts on remote ecosystems makes use of model-estimated degradation in air. Recent studies suggest these degradation rates to be overestimated, questioning current pesticide regulation. Here, we investigated the concentrations of 76 pesticides in Europe at 29 rural, coastal, mountain, and polar sites during the agricu...
Air quality is a globally pressing issue as it poses a major threat for human health and ecosystems. Non-methane volatile organic compounds (NMVOCs) are highly reactive substances and known for their impact on O3, HOx (OH + HO2) and NOx (NO + NO2) concentrations. NMVOCs comprise a variety of anthropogenic and biogenic compounds with highly complex...
Aliphatic hydrocarbons in PM2.5 samples from a residential area of Lagos, Nigeria, were quantified using a Curie-point pyrolysis–gas chromatography–mass spectroscopy (CPPGC/MS). The total concentrations of ∑n-alkanes (C20-C34), hopanes (∑4Hopanes), and steranes (∑3 Steranes) ranged from 1.8 to 146.6 ng m-3 (avg. 43.6 ± 35.1 ng m-3), 0.0 to 89.9 ng...
Carbohydrates, originating from marine microorganisms, enter the atmosphere as part of sea spray aerosol (SSA) and can influence fog and cloud microphysics as cloud condensation nuclei (CCN) or ice-nucleating particles (INP). Particularly in the remote Arctic region, significant knowledge gaps persist about the sources, the sea-to-air transfer mech...
The oceanic emission of dimethyl sulfide (DMS) plays a vital role in the Earth's climate system and is a significant source of uncertainty in aerosol radiative forcing. Currently, the widely used monthly climatology of sea surface DMS concentration cannot meet the requirement for accurately simulating DMS-derived aerosols by chemical transport mode...
Climate extremes in tandem with biodiversity change affect plant emissions of biogenic volatile organic compounds, as a result, the formation of biogenic secondary organic aerosols. The resulting biogenic secondary organic aerosols can have a wide variety of impacts, such as on Earth's radiative balance or cloud-and precipitation formation. However...
Accurate spatiotemporal estimation of non‐methane volatile organic compounds (NMVOCs) plays a pivotal role in establishing sophisticated early warning systems and formulating strategies to combat air pollution. Despite these critical applications, robust estimation of high spatiotemporal resolution NMVOCs concentrations remains a challenge. In this...
Residential wood combustion contributing to airborne particulate matter (PM10) was studied for 1 year at two sites in the village of Melpitz. Significant excess pollution was observed at the Melpitz center compared to that at the TROPOS research station Melpitz reference site, situated only 700 m away. Local concentration increments at the village...
Background
Epidemiological studies have related desert dust events to increased respiratory morbidity and mortality. Although the Sahara is the largest source of desert dust, Saharan dust (SD) has been barely examined in toxicological studies. Here, we aimed to assess the NLRP3 inflammasome-caspase-1-pathway-dependent pro-inflammatory potency of SD...
The climate effects of atmospheric aerosol particles serving as cloud condensation nuclei (CCN) depend on chemical composition and hygroscopicity, which are highly variable on spatial and temporal scales. Here we present global CCN measurements, covering diverse environments from pristine to highly polluted conditions. We show that the effective ae...
Climate extremes are on the rise. Impacts of extreme climate and weather events on ecosystem services and ultimately human well-being can be partially attenuated by the organismic, structural, and functional diversity of the affected land surface. However, the ongoing transformation of terrestrial ecosystems through intensified exploitation and man...
To fight against the first wave of coronavirus disease 2019 (COVID-19) in 2020, lockdown measures were implemented in most European countries. These lockdowns had well-documented effects on human mobility. We assessed the impact of the lockdown implementation and relaxation on air pollution by comparing daily particulate matter (PM), nitrogen dioxi...
Recent years have seen an increase in the use of wood for energy production of over 30%, and this trend is expected to continue due to the current energy crisis and geopolitical instability. At present, residential wood burning (RWB) is one of the most important sources of organic aerosols (OA) and black carbon (BC). While BC is recognized for its...
Chemical processing of reactive nitrogen species, especially of NOx (= NO + NO2) and nitrous acid (HONO), determines the photochemical ozone production and oxidation capacity in the troposphere. However, sources of HONO and NOx in the remote marine atmosphere are still poorly understood. In this work, the multiphase chemistry mechanism CAPRAM in th...
Gaseous nitrous acid (HONO) is a critical source of hydroxyl radicals (OH) in the troposphere. While both direct and secondary sources contribute to atmospheric HONO, direct emissions have traditionally been considered minor contributors. In this study, we developed δ15N and δ18O isotopic fingerprints to identify six direct HONO emission sources an...
Sulfuric acid represents a fundamental precursor for new nanometre-sized atmospheric aerosol particles. These particles, after subsequent growth, may influence Earth´s radiative forcing directly, or indirectly through affecting the microphysical and radiative properties of clouds. Currently considered formation routes yielding sulfuric acid in the...
T-dependent aqueous-phase rate constants were determined for the oxidation of the hydroxy aldehydes, glyceraldehyde, glycolaldehyde, and lactaldehyde, by the hydroxyl radicals (•OH), the sulfate radicals (SO4•-), and the nitrate radicals (NO3•). The obtained Arrhenius expressions for the oxidation by the •OH radical are: k(T,GLYCERALDEHYDE+OH•) = (...
We present the results of a ship-based field study about the sea-air transfer of marine combined carbohydrates (CCHO) from concerted measurements of the bulk seawater, the sea surface microlayer (SML), aerosol particles and fog. In seawater, CCHO ranged between 22–1070 µg L-1 with large differences among the different sea-ice related sea surface co...
Halogen atoms are important atmospheric oxidants that have unidentified daytime sources from photochemical halide oxidation in sea salt aerosols. Here, we show that the photolysis of nitrate in aqueous chloride solutions generates nitryl chloride (ClNO2) in addition to Cl2 and HOCl. Experimental and modeling evidence suggests that O(3P) formed in t...
Nitrate (NO3-) is a major component of atmospheric fine particles. Recent studies in eastern China have shown the increasing trend of NO3- in contrast to the ongoing control of nitrogen oxide (NOx). Here, we elucidate the effects of reduced sulfur dioxide (SO2) on the enhancement of NO3- formation based on field measurements at the summit of Mt. Ta...
Much attention has been paid to the world economy and social situations in response to the outbreak of war between Russia and Ukraine in the context of COVID-19. However, much less attention has been paid to the detrimental effect of war on the atmospheric environment. Here, we used an extended deweathered-detrended technique to quantitatively eval...
Atmospheric aerosol particles are a complex combination of primary emitted sources (biogenic and anthropogenic) and secondary aerosol resulting from aging processes such as condensation, coagulation, and cloud processing. To better understand their sources, investigations have been focused on urban areas in the past, whereas rural-background statio...
A 1-year aerosol chemical speciation monitor (ACSM) source analysis of organic aerosol particle contributions from anthropogenic sources after long-range transport at the TROPOS research station Melpitz Samira Atabakhsh et al. Correspondence to: Hartmut Herrmann (herrmann@tropos.de) The copyright of individual parts of the supplement might differ f...