What is fog, what is haze and what is haze?

Definition of (1) fog: When the relative humidity reaches 100%, the water vapor in the air will condense into tiny water droplets suspended in the air, which will reduce the visibility on the ground. This weather phenomenon is called fog.

It is more between February and April in spring. Forming conditions: cooling, humidifying and increasing water vapor content. There are radiation fog, advection fog, mixed fog and evaporation fog.

(2) Definition of smog: Particles such as dust, sulfuric acid, nitric acid and organic hydrocarbons in the air can also make the atmosphere turbid, blur the vision and worsen the visibility. If the horizontal visibility is less than 10000 meters, the visual distance obstacle caused by this aerosol system composed of non-aquatic products is called haze or dust haze, and the Hong Kong Observatory calls it haze.

(3) Definition of smog: Smog is a combination of fog and haze. Haze weather is a state of air pollution, and smog is a general term for all kinds of suspended particles in the atmosphere, especially PM2.5 (particles with aerodynamic equivalent diameter less than or equal to 2.5 microns) is considered as the "culprit" causing haze weather. Haze is the result of interaction between specific climatic conditions and human activities. In many areas of China, fog and haze are combined as disastrous weather phenomena for early warning and forecasting, which are collectively called "haze weather". The economic and social activities of high-density population will inevitably emit a large number of fine particles (PM 2.5). Once the emission exceeds the atmospheric circulation capacity and carrying capacity, the concentration of fine particles will continue to accumulate. At this time, if it is affected by calm weather, it is easy to have a wide range of smog.

The similarity between fog and haze is sight distance obstacle.

However, the reasons and conditions for the formation of fog and haze are quite different. Fog is a large number of tiny water droplets or ice crystals floating in the air, and the formation conditions should have a high water vapor saturation coefficient.

Generally speaking, atmospheric haze and blurred vision caused by relative humidity less than 80% are caused by haze; atmospheric haze and blurred vision caused by relative humidity greater than 90% are caused by fog; atmospheric haze and blurred vision caused by relative humidity between 80 and 90% are caused by a mixture of fog and haze, but its main component is haze. The thickness of smog is relatively large, which can reach 1 ~ 3 km.

(4) Difference between fog and haze: "Fog" and "haze" are actually different. Fog refers to the weather phenomenon that the visibility is lower than 1 km due to the condensation of suspended water vapor in the atmosphere; The formation of smog is mainly the result of a large number of suspended particles in the air and meteorological conditions.

1. When fog appears, the air relative humidity often reaches 100% or approaches 100%. With the daily change of air humidity, fog is more common or thicker in the morning and evening, and it becomes lighter or even disappears during the day. The effective horizontal visibility is less than 1KM in fog. The effective horizontal visibility at 1 ~ 10 km is called light fog. Fog refers to the weather phenomenon that the visibility is lower than 1 km due to the condensation of suspended water vapor in the atmosphere.

2. When the smog occurs, the relative humidity is not large, but it is saturated in the fog (if there are a lot of condensation nuclei, the relative humidity may not reach 100%, which may lead to saturation). Smog is caused by pollutants such as automobile exhaust. When the relative humidity is between 80% and 90%, the visibility deterioration caused by blurred vision is caused by the mixture of haze and fog.

3. When water vapor condensation intensifies and air humidity increases, haze will turn into fog. The difference between haze and fog is that the relative humidity is small when haze occurs, but it is saturated in fog (if there are a large number of condensation nuclei, the relative humidity may not reach 100%, and saturation may occur).

In fact, fog and haze are very different from a certain point of view. For example, when fog appears, the air is humid; When smog occurs, the air is relatively dry and the relative humidity of the air is usually below 60%. The reason is that a large number of extremely fine dust particles, smoke particles and salt particles float evenly in the air, which makes the air with effective horizontal visibility less than 10KM turbid. The symbol is "∞". The diurnal variation of haze is generally not obvious. When the air mass changes little and is stable, it lasts for a long time, sometimes exceeding 10 days. Due to the weather phenomena such as smoke, light fog, sandstorm, sand blowing and floating dust, the effective horizontal visibility is less than 10KM due to the influence of a large number of extremely fine dust particles or smoke particles floating in the air. Sometimes it is difficult for meteorological professionals to tell the difference. It is necessary to comprehensively analyze and judge the weather background, sky conditions, air humidity, color and smell, satellite monitoring and other factors to draw a correct conclusion. The weather phenomena of fog and haze can sometimes be converted to each other. Haze is harmful to human body after being inhaled into human respiratory tract. If inhaled for a long time, it will lead to death in severe cases.

(5) Preventive measures

1, open the window less in foggy days. When going out, you must wear a mask, drink plenty of water, soak chrysanthemum tea and other Chinese herbal teas to prevent diseases, eat more fruits, and thoroughly clean your skin and hair after coming home from the outside. In addition, the elderly who like morning exercises and shopping in the food market should pay attention to reducing going out, because smog is extremely harmful to the health of the elderly.

Step 2 wear a mask when you go out

Step 3 drink more tea

4, the right amount of vitamin D.

5. Eat lightly and drink plenty of water

Step 6 eat more vegetables

7. Minimize going out in foggy days [5]?

8. Pay attention to the speed when driving.

9. Protect yourself when going out, wear a special anti-fog PM2.5 mask and anti-fog nose mask, filter PM2.5, and breathe fresh air anytime and anywhere.

10, avoid moving in foggy days. You can do morning exercises after the sun comes out. You can also switch to indoor sports.

1 1. The patient insisted on taking the medicine. Patients with respiratory diseases and cardiovascular and cerebrovascular diseases should insist on taking medicine on time in foggy days.

12, don't close the window too tightly. You can choose to open the window for a short time at noon with sufficient sunshine and less pollutants.

13, try to stay away from the road. The concentration of pollutants is the highest when large cars enter the city during peak hours and at night.

14, calcium, vitamin d, eat more tofu, Sydney, etc.