Reducing Air Pollution With the help of Nitrogen Oxides Links to Airborne Sulphates

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Fog, as we know it, is a visible aerosol that is composed of ice crystals or tiny water droplets suspended in the air near or at the Earth’s surface. Significant inconvenience for many mega-cities and the people from these in Mainland China was the hazy and dense fog events. The characteristics of these fog episodes are excessive humidity, low visibility, and intensely excessive PM2. Haze appears most often when dust and smoke particles collect in relatively dry air resulting in a usually low-hanging shroud that impairs visibility and may become a respiratory health threat. Among pollutants that are less than 2.5 microns in diameter (PM2.5), airborne sulfate is one of the most common components of hazy air pollution formed atmospherically through the oxidation of sulfur dioxide (SO2).

Compared to the reactant-product connection between sulfur dioxide and airborne sulfate, the advanced oxidants, and mechanisms that allow this transformation should not form widespread data. In particular, the function of nitrogen oxides in sulfate ‘genesis’ is not clear. Governments and researchers were struck with sulfate air pollution. Managing it is difficult as it is not generated from air pollution’s usual sources, like nitrogen oxides, which are emitted from vehicles, and the oxidization of fossil fuels like coal, natural gas, and diesel.

Reducing Air Pollution With the help of Nitrogen Oxides Links to Airborne Sulphates

“Since sulfate is formed atmospherically and cannot be controlled directly, we must target its precursor components (such as sulfur dioxide and nitrogen oxides). Effective reduction of sulfate content in the air relies on knowledge of the quantitative relationship it has with its precursors. This work lays the conceptual framework to delineate the relationship between sulfate and one set of its controllable precursors, nitrogen oxides (NOx) — the low and extremely high concentration of NOx could both fuel up the production of sulfate. The policymakers should pay attention to when they try to control the emission of NOx,” explained Prof. Yu Jianzhen, Professor at HKUST’s Department of Chemistry and Division of Environment and Sustainability.

Based on these findings show that to be able to scale back sulfate ranges in extremely polluted haze-fog events, co-management of SO2 and NOx emissions is crucial.