On Tuesday the 22nd, there will be many clouds across the country, and rain is expected in some areas. In the morning, rain may start on Jeju Island, in the afternoon in the Jeonnam area, and at night in the Gyeongnam area. Other regions may also get rain late in the day. The forecast says temperatures will be 11~19 degrees in the morning and 17~25 degrees in the daytime. There will not be strong cold weather, but the day and night temperature difference may be a little big. Sea waves are expected to stay relatively low in the East Sea, West Sea, and South Sea coastal waters. But in this weather, what stands out more is the air quality. Because of the yellow dust that came in on the 21st, fine dust levels across the country are expected to be at the 'bad' level. Especially, PM10 may rise to 'very bad' from late morning to afternoon, but ultrafine dust PM2.5 was shown as 'normal'.
원문 보기
When yellow dust news appears, why do fine dust articles come with it too?
When you first watch Korean news, it can be a little confusing. They say yellow dust is coming, and also that fine dust is bad, and on some days they even talk separately about ultrafine dust. But these three are not just the same words repeated. Yellow dust is a phenomenon of soil dust flying in from dry areas in northern China and Mongolia, and fine dust is a measurement standard that checks small particles floating in the air by size.
So in the news, the two always come together. The cause is explained like 'yellow dust came in,' and the result is explained like 'the PM10 number went up.' In simple words, yellow dust tells you 'why the air became hazy,' and fine dust shows 'how bad the number is now.'
There is one more important point here. Even if yellow dust comes, ultrafine dust PM2.5 does not always rise sharply together. Yellow dust is more directly connected to relatively bigger soil particles, so it often pushes up PM10 first. PM2.5 is affected more by other factors like car exhaust, heating, industrial burning, and chemical reactions in the air. So on some days, a slightly strange sentence like 'fine dust very bad, ultrafine dust normal' really appears.
Yellow dust is an incoming phenomenon, and fine dust is a measured number.
During yellow dust, PM10 usually gets worse first and more strongly.
Yellow dust, fine dust, and ultrafine dust: the names are similar, but the standards are different
| Item | Yellow dust | Fine dust PM10 | Ultrafine dust PM2.5 |
|---|---|---|---|
| What it is | A soil dust phenomenon blown in from deserts and dry areas | Measured value of particles with diameter 10㎛ or less | Measured value of particles with diameter 2.5㎛ or less |
| Main cause | Dust moving from northern China, Mongolia, and other places | Yellow dust, scattered dust, road dust, some combustion pollution | Car exhaust, heating, industrial combustion, secondary formation |
| Role in the news | Explains why the air looks hazy | Shows with numbers how bad the current air quality is | A number that shows how serious the health risk is |
| Seasonality | Especially common in spring | Can happen all year | Can happen all year |
| Relation to yellow dust | The cause itself | Most likely to rise together directly | Depending on the situation, it may rise more or less |
Why can PM10 be very bad while PM2.5 is normal
| Comparison item | PM10 | PM2.5 |
|---|---|---|
| Size feel | Particles smaller than about 1/5 of the thickness of a hair | Particles much smaller than PM10 that can go deep into the lungs |
| Situations when it rises easily | Yellow dust, soil dust, construction site dust, road scattered dust | Combustion pollution, exhaust gas, stagnant air, chemical reactions |
| Where it touches the body first | Upper airways like the nose, throat, and bronchi | Deep in the alveoli, and some are linked to whole-body inflammatory responses |
| Main symptoms | Irritation like stinging eyes, a scratchy throat, and coughing stands out | Even if it feels weak on the outside, the health risk can be bigger |
| Decision to go out | On days with heavy yellow dust, masks and eye protection are especially important | If you look at health risk carefully, you need to be more cautious |
Yellow dust has existed since old times, so why did it become 'spring disaster news' in the 2000s?
Yellow dust itself is an old phenomenon, but it became the center of nationwide news only relatively recently.
Step 1: Yellow dust was not a new phenomenon
Even in records from Samguk Sagi and the Joseon period, there are expressions like yellow soil rain and dust. So yellow dust was originally a natural spring phenomenon that came to the Korean Peninsula.
Step 2: Since the 1980s, the felt frequency increased
If you look at modern observation data, based on Seoul, the frequency of yellow dust after 1980 clearly increased. It existed before too, but this was the time when modern Koreans started to feel, 'Why does it come so often these days?'
Step 3: From the 1990s, it started to be managed with numbers
For yellow dust to become news instead of just a seasonal phenomenon, records and statistics were needed. From the early 1990s, as modern observations and statistics built up, yellow dust became something talked about not by 'feeling' but by 'numbers'.
Step 4: 2001~2002 changed the mood
In 2001, the number of yellow dust days increased a lot and gave society a shock, and around 2001~2002, heavy metal analysis and discussion of health effects began in earnest. From this time, yellow dust moved from just 'the sky looks hazy' to the question 'Is it dangerous to health?'
Step 5: Now it is the era of international forecasting models
Since the mid-2000s, source area monitoring, Korea-China-Mongolia cooperation, satellite data, and forecasting models started to be added. In the 2020s, with even a Korean-style integrated forecasting model introduced, yellow dust became not just a natural spring phenomenon but an environmental issue monitored by the country in real time.
Why the whole country gets tense at the same time: this is how air quality forecasts are made
| Item | Explanation |
|---|---|
| Why it becomes nationwide news | Yellow dust and pollution coming from outside the country often enter from the west and move across wide areas, so you cannot look at only Seoul separately. |
| Who makes the forecast | The Air Quality Integrated Forecast Center of the National Institute of Environmental Research under the Ministry of Environment takes the main role, and yellow dust information and weather forecasts from the Korea Meteorological Administration are also reflected together. |
| What data they use | They make forecasts by combining ground measurement networks, weather forecasts, emissions data, and environmental satellite data together. |
| PM10 grade standard | Good 0~30, Normal 31~80, Bad 81~150, Very bad 151 and above(㎍/㎥) |
| PM2.5 grade standard | Good 0~15, Normal 16~35, Bad 36~75, Very bad 76 and above(㎍/㎥) |
| Difference between forecast and alert | A forecast tells you the future concentration in advance, and an alert is issued when the actual concentration stays above the standard. |
When it rains, does yellow dust really get washed away
This is a question people always get curious about after going through spring a few times in Korea. In the news, they often say, 'If it rains, fine dust will get better.' In fact, rain sticks to particles in the air and makes them fall to the ground. This is called wet removal. Simply put, it is like wiping the sky once with a wet cloth.
But there is a catch here too. Bigger particles like yellow dust are washed away well by rain, but very small particles like PM2.5 may not go down as much as you expect with light rain or short rain. Also, if pollution keeps coming in from outside or the air is stagnant, the air quality can stay 'Bad' even when it rains.
It is easy to understand the different rain start times by region for the same reason. Rain clouds do not come like a wall covering the whole country at once. They are closer to a moving band. It may start first in Jeju and then spread later to South Jeolla and South Gyeongsang. So one area may already have rain, while another area still has yellow dust and a hazy sky at the same time.
In the end, this is the simple everyday point. Instead of feeling safe just because you hear 'It will rain,' you should check the amount of rain, how long it lasts, and the PM2.5 level together. A day when your throat feels scratchy because of yellow dust and a day when ultrafine dust has built up deeply need slightly different responses.
If a yellow dust forecast appears, check the PM10 number first, and if you are worried about your health, check PM2.5 too.
Even if there is rain in the forecast, if the rainfall is small, the air quality improvement may be limited.
We will tell you how to live in Korea
Please give lots of love to gltr life