Nitrogen oxides and sulfur oxides are one of the important factors that cause haze weather. Na _ 2S _ 2O _ 4 and nitrate are obtained by absorbing sulfur dioxide and nitric oxide.

Sulfur dioxide and nitrogen oxides have certain toxicity and pungent odor.

Sulfur dioxide, also known as sulfur dioxide, is the most common sulfur oxide, the main component of sulfuric acid feed gas and one of the main air pollutants. Colorless, with a strong pungent smell. This gas is emitted when a volcano erupts, and sulfur dioxide is also produced in many industrial processes. Because coal and oil usually contain sulfur-containing compounds, sulfur dioxide will be produced when burned. When sulfur dioxide is dissolved in water, it will form sulfurous acid (the main component of acid rain).

Sulfur trioxide, also known as sulfuric anhydride, is one of the products of sulfuric acid industry. It is a colorless liquid at normal pressure and room temperature, with melting point 16.8℃ and boiling point of 44.8℃. It smokes strongly in the atmosphere, forming a sulfuric acid fog that is difficult to settle. When melting and polymerizing sulfur trioxide, explosion may occur due to the high vapor pressure before melting.

Nitrogen oxides include many compounds, such as nitrous oxide (N2O), nitric oxide (N0), nitrogen dioxide (NO2), nitrogen trioxide (N2O 3), nitrogen tetroxide (N2O 4) and nitrogen pentoxide (N2O 5). Except nitrogen dioxide, other nitrogen oxides are extremely unstable and wet when exposed to light. Nitric oxide becomes nitrogen dioxide. Therefore, the occupational environment is exposed to several gas mixtures, often called smoke (gas), mainly nitric oxide and nitrogen dioxide, and nitrogen oxides are mainly nitrogen dioxide. Nitrogen oxides have different degrees of toxicity.

Nitrogen oxides can stimulate the lungs, making it difficult for people to resist respiratory diseases such as colds. People with respiratory diseases such as asthma are more susceptible to nitrogen dioxide. For children, nitrogen oxides may cause lung development damage. Some studies have pointed out that long-term inhalation of nitrogen oxides may lead to changes in lung structure, but it is still uncertain about the content of nitrogen oxides and the time of inhaling gas.

Nitrous oxide in nitrogen oxides is used as an inhalation anesthetic, not an industrial poison; In addition to nitrogen dioxide, nitrogen dioxide will also be produced when exposed to light, humidity or heat, which is mainly toxic to the deep respiratory tract. Nitric oxide can also combine with hemoglobin to cause methemoglobinemia. The MLC of human inhaling nitrogen dioxide 1 min is 200ppm.

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