まとめ
窒素酸化物は,主に化学的変換によって都市空気から除去され,大気中の平均寿命は5〜6時間です. この研究では,ボストンの羽根の除去率を定量化しています.
科学分野:
- 大気化学 大気化学
- 環境科学 環境科学
背景:
- 窒素酸化物 (NOx) は,スモッグや酸雨に寄与する主要な大気汚染物質です.
- NOx除去率を理解することは,都市環境における空気質管理に極めて重要です.
研究 の 目的:
- ボストンの都市風雲の中で窒素酸化物 (NOx) の除去と変換の速度を決定する.
- 特定の都市条件下でNOxの大気中の寿命を定量化するために.
主な方法:
- 空中測定はボストンの都市圏内で行われました.
- NOx除去のための擬似ファーストオーダーの速度定数は,日光条件下で計算された.
主要な成果:
- NOx除去の平均的な偽第一次元の速度定数は,0.18/時間 (範囲:0.140.24/時間) でした.
- 識別された主要な除去経路は,窒素酸と有機窒素酸への化学的変換でした.
- 計算された除去率は,都市空気のNOxの大気中の寿命が約5〜6時間であることを示しています.
結論:
- 都市圏の大気中のNOxは,大気中の寿命が比較的短く,約5~6時間です.
- 窒素酸と有機窒素酸への化学的変換は,NOx除去の主なメカニズムです.
- 空気中での測定は,大気汚染物質の動態を理解するために貴重なデータを提供します.
関連する概念動画
Overview of Nitrogen Metabolism
Nitrogen is a very important element for life because it is a major constituent of proteins and nucleic acids. It is a macronutrient, and in nature, it is recycled from organic compounds and stored in the form of ammonia, ammonium ions, nitrate, nitrite, or nitrogen gas by many metabolic processes. Many of these metabolic processes are carried out only by prokaryotes.
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
The largest pool of nitrogen available in the terrestrial ecosystem is gaseous nitrogen (N2) from the air, but this nitrogen...
Electrophilic Aromatic Substitution: Nitration of Benzene
The nitration of benzene is an example of an electrophilic aromatic substitution reaction. It involves the formation of a very powerful electrophile, the nitronium ion, which is linear in shape. The reaction occurs through the interaction of two strong acids, sulfuric and nitric acid.
2° Amines to N-Nitrosamines: Reaction with NaNO2
Secondary amines react with nitrous acid to form N-nitrosamines, as depicted in Figure 1. Nitrous acid, a weak and unstable acid, is formed in situ from an aqueous solution of sodium nitrite and strong acids, such as hydrochloric acid or sulfuric acid, in cold conditions. In the presence of an acid, the nitrous acid gets protonated. The subsequent loss of water results in the formation of the electrophile known as nitrosonium ion.
The Equilibrium Constant
Consider the oxidation of sulfur dioxide:
The Nitrogen Cycle
Nitrogen atoms, present in all proteins and DNA, are recycled between abiotic and biotic components of the ecosystem. However, the primary form of nitrogen on Earth is nitrogen gas, which cannot be used by most animals and plants. Thus, nitrogen gas must first be converted into a usable form by nitrogen-fixing bacteria before it can be cycled through other living organisms. The use of nitrogen-containing fertilizers and animal waste products in human agriculture has greatly influenced the...
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview
Nitrous acid and nitric acids are two types of acids containing nitrogen, among which nitrous acid is weaker than nitric acid. Nitrous acid with a pKa value of 3.37 ionizes in water to give a nitrite ion and the hydronium ion.
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...


