Try to avoid going out! Beijing launches orange alert for severe air pollution. How can you protect yourself?

According to the Beijing Ecological Environment Monitoring Center, Beijing will experience a moderate PM2.5 pollution process from October 30 to November 2. At 12:00 today (30th), Beijing activated the orange warning signal for severe air pollution. This is the first severe air pollution warning activated after the revision of the Beijing Air Pollution Emergency Plan (Revised in 2023).

According to data from the Beijing Ecological Environment Monitoring Center, at 9 a.m. this morning, Beijing's air quality was "moderately polluted" and Fengtai was heavily polluted.

Image source: Beijing Ecological Environment Monitoring Center

It is expected that from the afternoon to the night of the 30th, the ground wind will turn to be dominated by southerly winds. Affected by the backflow of pollution, cities such as Beijing and Tianjin may experience short-term moderate to severe pollution.

On the 31st, the region will be dominated by southwesterly winds. It is expected that the central part of Beijing-Tianjin-Hebei will be dominated by moderate to heavy pollution, the southern part will be dominated by light to moderate pollution, and other areas will be dominated by good to light pollution.

From November 1 to 2, pollution eased slightly, with light to moderate pollution being the main condition in the central and southern parts of Beijing-Tianjin-Hebei. Cities in central Hebei still face the risk of heavy pollution on a daily basis.

Starting from the 3rd, regional diffusion conditions gradually improved, and pollution gradually cleared from north to south.

Image source: China National Meteorological Administration

According to the Central Meteorological Bureau, over the next three days, there will be heavy to dense fog in some areas of central and eastern Beijing, Tianjin, central and southern Hebei, Jiangsu and other places from night to early morning, with local visibility less than 200 meters in some areas.

Image source: China National Meteorological Administration

Why is smog common in autumn and winter?

According to Zhang Tao, chief forecaster of the Central Meteorological Observatory, the main weather conditions in China during autumn and winter are actually two types: cold air weather and pre-cold air weather. Fog and haze can both be considered as "pre-cold air" weather.

Before the arrival of cold air, the atmosphere will be "calm and stable", which is often referred to as "poor air pollution diffusion conditions". In a calm and stable situation, man-made or natural atmospheric suspended particles will accumulate in the low altitude near the ground, causing haze in dry conditions and fog in wet conditions. This situation will continue as long as the next cold air arrives.

From a national perspective, in the next few days, except for a small amount of cold air that will slide eastward from northern Xinjiang through Mongolia and then across the northern part of Northeast China, most of my country's middle and eastern regions will not be affected by significant cold air and are in a "front cold air" situation.

The disastrous low visibility caused by fog and haze mainly occurs during the coldest period from the second half of the night to the early morning, which is also the most "calm" period.

Overall, the visibility caused by haze weather will not be too low. Low visibility is mainly caused by heavy fog, especially in the Beijing-Tianjin-Hebei region and Jiangsu. In the past half month, if it were 10 years ago, there would undoubtedly be a large-scale and long-term heavy pollution weather in North China and the Huanghuai region. However, thanks to the effectiveness of pollution control, the fog and haze are much lighter under the same weather conditions as in the past. This "lightness" is not only lighter in degree, but also shorter in duration.

How can we protect ourselves in the face of heavily polluted weather?

The public should pay attention to the local heavy pollution weather forecast and warning information. When heavy pollution weather occurs, exposure should be reduced as much as possible. The main measures include:

1. The public should reduce outdoor activities.

2. Children, pregnant women, the elderly, and patients with cardiovascular and respiratory diseases should try to avoid outdoor activities.

3. Close doors and windows in time, do not smoke indoors, and avoid cooking and other behaviors that may aggravate indoor air pollution. If there is no fresh air fan installed indoors, try to avoid peak pollution periods according to local air pollution conditions and open windows for ventilation 1-2 times a day for 10-20 minutes each time. If there are many people indoors and the space is small, the number of window openings should be appropriately increased.

4. If conditions permit, use air purification equipment.

5. Correctly choosing and wearing a mask can reduce the impact of PM2.5 on human health. If you must go out, it is recommended to give priority to using a mask marked with the GB/T 32610-2016 standard, and try to reduce the time and intensity of outdoor activities; wash your face and exposed skin in time after going out.

6. It is best to choose public transportation when traveling. If you need to travel by bicycle, electric vehicle, etc., you should be more careful and slow down to avoid traffic accidents.

Comprehensive sources: Xinhuanet, National Joint Center for Air Pollution Control, China Meteorological Administration, Beijing Daily, Beijing News, etc.