Can atmospheric chemistry deposition schemes reliably simulate stomatal ozone flux across global land covers and climates?

The risk of ozone pollution to plants is estimated based on the flux through the plant pores which still has uncertainties. In this study, we estimate this quantity with nine models at different land types worldwide, driven by measurement data. The models mostly estimated reasonable summertime ozone flux to plants. The model results varied by land cover, mainly related to the a lack of moisture in the soil. This work is an important step for assessing the ozone impact on vegetation.

The influence of ammonia emission inventories on size-resolved global atmospheric aerosol composition and acidity

Ammonia (NH3) is an abundant alkaline gas and key precursor in particulate matter formation. While SO2 and NOx emissions have decreased, global NH3 emissions are stable or rising. This study investigates NH3 emission impacts on size-resolved aerosol composition and acidity using the EMAC (ECHAM5/MESSy Atmospheric Chemistry) model, analyzing three emission schemes. Sulfate–nitrate–ammonium aerosols in fine-mode sizes are most sensitive to NH3 changes. Regional responses vary. NH3 buffers aerosol acidity, mitigating pH shifts.

Aerosol composition trends during 2000–2020: in-depth insights from model predictions and multiple worldwide near-surface observation datasets

This study examines global changes in air pollution from 2000 to 2020, focusing on fine aerosols that impact climate and health. Using models and global data, it finds that organic aerosols dominate in many regions, especially with wildfires or natural emissions. Pollution from sulfate and nitrate has decreased in Europe and North America due to regulations, while trends in Asia are more complex. The findings improve understanding and support policies for cleaner air and healthier environments.

Observationally constrained analysis on the distribution of fine- and coarse-mode nitrate in global models

A key challenge in simulating the life cycle of nitrate aerosol in global models is accurately representing the mass size distribution of nitrate aerosol, which lacks sufficient observational constraints. We found that most global models underestimate the mass fraction of fine-mode nitrate at the surface in all regions. Our study highlights the importance of gas–aerosol partitioning parameterization and the simulation of dust and sea salt in correctly simulating the mass size distribution of nitrate.

Ground-based tropospheric ozone measurements: regional tropospheric ozone column trends from the TOAR-II/HEGIFTOM homogenized datasets

Tropospheric ozone is an important greenhouse gas and an air pollutant whose distribution and time variability are mainly governed by anthropogenic emissions and dynamics. In this paper, we assess regional trends of tropospheric ozone column amounts, based on two different approaches of merging or synthesizing ground-based observations and their trends within specific regions. Our findings clearly demonstrate regional trend differences but also consistently higher pre-COVID than post-COVID trends.

Organic Solvents-Based Offline Aerosol Mass Spectrometry (SOff-AMS) for Comprehensive Chemical Characterization of Ambient Organic Aerosol

While air pollution is a worldwide problem, it is often not logistically and financially viable to transport or set up advanced mass spectrometry instruments to study airborne particles directly on site. In such cases filter samples are collected but existing laboratory techniques characterize only a fraction of their composition. As a result, understanding the full spectrum of sources of air pollution especially in many population-dense and frequently resource-thin regions of the world is hindered. Now consider the possibility of being able to measure a fair bit in a laboratory what otherwise almost invariably requires taking complex instrumentation on site. SOff-AMS could potentially allow for studying and apportioning sources, especially in regions of the world that are impacted by both primary and secondary contributors, facilitating efforts for improving and protecting the public health.

Unraveling the global response of secondary atmospheric pollutants to emission reductions imposed during the COVID-19 pandemic

This study employs the global chemistry–climate model EMAC, combined with emission adjustment factors (CONFORM), to evaluate the global impacts of the 2020 COVID-19 lockdowns on secondary air pollutants. Unlike earlier studies limited to short periods or specific regions, this work captures seasonal, spatial, and sectoral variability in emissions and pollutant formation.

Photochemical aging of aviation emissions: transformation of chemical and physical properties of exhaust emissions from a laboratory-scale jet engine combustion chamber

Photochemical reactions altered the properties of kerosene-operated jet engine burner exhaust emissions, which were studied in a laboratory using an oxidation flow reactor. Particle mass increased 300-fold as particles and gases became more oxidized. Light absorption increased, but the total direct radiative forcing efficiency was estimated to have shifted from positive to negative. The results highlight the importance of considering secondary aerosol formation when assessing the impacts of aviation.

Widespread reduction of ozone extremes in storylines of future climate

By constructing storylines of future climate with fixed anthropogenic emissions, we quantify how temperature and humidity changes affect ozone and associated mortality. Here, we show that locally, vegetation and photochemistry often act in concert to amplify ozone pollution extremes, while increased humidity in the free troposphere tends to suppress background ozone levels.

Influence of nitrogen oxides and volatile organic compounds emission changes on tropospheric ozone variability, trends and radiative effect

Satellites and model simulations show enhancement in tropospheric ozone, which is highly impacted by human-produced nitrous oxides compared to volatile organic compounds. The increased amount of ozone enhances ozone radiative forcing. The ozone enhancement and associated radiative forcing are the highest over South and East Asia. The emissions of nitrous oxides show a higher influence on shifting ozone photochemical regimes than volatile organic compounds.

2025

2024

2023

2021 - 2022

2015 - 2020

2014 and before