The Japan Meteorological Agency has observed kosa since 1967, and the data obtained there shows the following: Both the number of kosa occurrences and the total number of days when kosa was observed were maximum in 2002, but the long-term trend is not clear because the data changed considerably depending on the year.
日本の気象庁の観測では、1967年の観測開始以降、2002年に黄砂観測の日数・延べ日数が共に最多を記録したが、年ごとの変化が大きいため長期的な変化傾向ははっきりと判明していない。