Observation-Based Diagnostics of Reactive Nitrogen Recycling through HONO Heterogenous Production: Divergent Implications for Ozone Production and Emission Control.

Understanding of nitrous acid (HONO) production is crucial to photochemical studies, especially in polluted environments like eastern China. In-situ measurements of gaseous and particulate compositions were conducted at a rural coastal site during the 2018 spring Ozone Photochemistry and Export from China Experiment (OPECE). This data set was applied to investigate the recycling of reactive nitrogen through daytime heterogeneous HONO production.

Decreasing Production and Potential Urban Explosion of Nighttime Nitrate Radicals amid Emission Reduction Efforts.

Nighttime oxidation by nitrate (NO) radicals has important ramifications on nocturnal aerosol formation and hence the climate and human health. Nitrate radicals are produced by the reaction of NO and O. Despite large decreases in anthropogenic emissions of nitrogen oxides (NO = NO + NO), a previous study found significant increases in NO production (PNO) from 2014 to 2019 in China, in contrast to decreasing trends in the U.

Collection of Nitrogen Dioxide for Nitrogen and Oxygen Isotope Determination─Laboratory and Environmental Chamber Evaluation.

The family of atmospheric oxides of nitrogen, NO (e.g., nitrogen oxides (NO) + nitric acid (HNO) + nitrous acid (HONO) + peroxyacetyl nitrate (PAN) + particulate nitrate (pNO) + other), have an influential role in atmospheric chemistry, climate, and the environment.

Airborne Emission Rate Measurements Validate Remote Sensing Observations and Emission Inventories of Western U.S. Wildfires.

Carbonaceous emissions from wildfires are a dynamic mixture of gases and particles that have important impacts on air quality and climate. Emissions that feed atmospheric models are estimated using burned area and fire radiative power (FRP) methods that rely on satellite products. These approaches show wide variability and have large uncertainties, and their accuracy is challenging to evaluate due to limited aircraft and ground measurements.

Global Emissions of Hydrogen Chloride and Particulate Chloride from Continental Sources.

Gaseous and particulate chlorine species play an important role in modulating tropospheric oxidation capacity, aerosol water uptake, visibility degradation, and human health. The lack of recent global continental chlorine emissions has hindered modeling studies of the role of chlorine in the atmosphere. Here, we develop a comprehensive global emission inventory of gaseous HCl and particulate Cl (pCl), including 35 sources categorized in six source sectors based on published up-to-date activity data and emission factors.

Chemical Production of Oxygenated Volatile Organic Compounds Strongly Enhances Boundary-Layer Oxidation Chemistry and Ozone Production.

Photolysis of oxygenated volatile organic compounds (OVOCs) produces a primary source of free radicals, including OH and inorganic and organic peroxy radicals (HO and RO), consequently increasing photochemical ozone production. The amplification of radical cycling through OVOC photolysis provides an important positive feedback mechanism to accelerate ozone production. The large production of OVOCs near the surface helps promote photochemistry in the whole boundary layer.

No Evidence for a Significant Impact of Heterogeneous Chemistry on Radical Concentrations in the North China Plain in Summer 2014.

The oxidation of nitric oxide to nitrogen dioxide by hydroperoxy (HO) and organic peroxy radicals (RO) is responsible for the chemical net ozone production in the troposphere and for the regeneration of hydroxyl radicals, the most important oxidant in the atmosphere. In Summer 2014, a field campaign was conducted in the North China Plain, where increasingly severe ozone pollution has been experienced in the last years. Chemical conditions in the campaign were representative for this area.