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.

Optimized step size control within the Rosenbrock solvers for stiff chemical ordinary differential equation systems in KPP version 2.2.3_rs4

Model simulations are essential for understanding the interactions between atmospheric composition and weather. However, models including chemistry are very slow. Hence, any computation speedup of such models is important for understanding the role of atmospheric chemistry within the Earth system. In this study we analyzed and optimized the time step for chemistry calculations. Our results show that atmospheric models could be run notably faster without any loss in accuracy.

Global ground-based tropospheric ozone measurements: reference data and individual site trends (2000–2022) from the TOAR-II/HEGIFTOM project

Tropospheric ozone is an important greenhouse gas and is an air pollutant. The time variability of tropospheric ozone is mainly driven by anthropogenic emissions. In this paper, we study the distribution and time variability of ozone from harmonized ground-based observations from five different measurement techniques. Our findings provide clear standard references for atmospheric models and evolving tropospheric ozone satellite data for the 2000–2022 period.

The legacy of the U.S. Clean Air Act at a crossroads

Chronic and acute exposure to elevated concentrations of ambient fine particulate matter represents a significant health risk. Here, we evaluate the avoided air pollution due to the U.S. Clean Air Act and the potential of the 2016 Paris Agreement to improve air quality in the contiguous U.S. The current weakening of federal agencies in the U.S. will degrade environmental quality, induce sickness and death, and incur costs.

Ozone Production Efficiencies in the Three Largest United States Cities from Airborne Measurements

This study utilizes aircraft-based measurements from a field campaign in summer 2023 to compare the efficiency of ozone production in the three largest US cities.

Semi-volatile oxygenated organics and ammonium chloride increasing sub-micron aerosol hygroscopicity, cloud condensation nuclei and PM1 mass in the Delhi region

Delhi-NCR continues to experience extreme particulate pollution during the winter season, with implications for both health and climate. In this study, we carried out over a month of HR-ToF-AMS-based chemical characterization of sub-micron particles (PM₁) at a background site in Delhi, coupled with CCN measurements, lab experiments, and back-trajectory analysis.

2025

2024

2023

2021 - 2022

2015 - 2020

2014 and before