What Is “Kosa” (Asian Dust)?

泰良富樫
Feb 1
4 min read

What Travelers Should Know Before Visiting the Kansai Area in Spring

While winter cold still lingers, the weather gradually becomes milder as March approaches.In cities such as Kyoto and Osaka, plum blossoms and cherry blossoms begin to bloom, making this one of the most popular seasons for travel.

However, spring in the Kansai region also brings a natural phenomenon known as “Kosa” (Asian dust).Even during a short stay, Kosa can affect your health, so international visitors should be aware of it before traveling.

When and Where Does Kosa Come From?

Why March in Kansai Requires Extra Caution

Kosa occurs when fine sand particles from desert regions of the Asian continent are lifted into the air and carried to Japan by strong westerly winds.

In Japan, Kosa is observed more frequently from March to May, and the Kansai region is considered one of the areas most affected.

According to observations by the Japan Meteorological Agency, on days with heavy Kosa, the sky may appear hazy or whitish, and distant mountains or buildings become difficult to see.This is often one of the easiest signs for travelers to notice while sightseeing.

How to Tell When Kosa Levels Are High in Kyoto or Osaka

Kosa may be present if you notice the following:

The sky looks cloudy or misty, even without fog
Clothes feel dusty or gritty
Irritation in the eyes or throat

On such days, Kosa particles may be present in the air.

How Kosa Can Affect the Health of International Travelers

Kosa particles are extremely small and can carry air pollutants such as PM2.5, as well as bacteria. When these particles enter the body, they may cause various health symptoms.

Effects on the Respiratory System

Coughing, Sore Throat, and Shortness of Breath

Inhaling Kosa can lead to symptoms such as a sore throat, coughing, or a runny nose.During travel, people often walk longer distances and breathe more deeply, which can increase exposure and make symptoms more noticeable.

Extra Caution for Travelers with Asthma or Chronic Respiratory Conditions

For individuals with asthma or chronic obstructive pulmonary disease (COPD), symptoms may worsen suddenly.If you begin to feel even mild shortness of breath, avoid pushing yourself and consider resting or seeking medical care.

Allergy-Like Symptoms

Why Kosa Can Feel Similar to Hay Fever

Kosa can trigger allergic reactions, including sneezing, nasal congestion, and a runny nose.Because these symptoms resemble seasonal allergies, some travelers may not realize Kosa is the cause and may delay appropriate care.

Effects on the Eyes and Skin

Common Issues During Sightseeing

Itchy or red eyes, as well as skin redness or a stinging sensation, are also common symptoms associated with Kosa.Contact lens users should be particularly cautious during this season.

Practical Ways to Protect Yourself from Kosa in Kansai in March

Protection While Outdoors

Choosing the Right Mask and Sunglasses

Non-woven masks with PFE or VFE filtration are effective at blocking fine particles.Sunglasses or regular glasses can also help reduce irritation to the eyes.

Kosa-Related Items Available at Japanese Drugstores

In Japan, drugstores widely sell masks, eye drops, and allergy medications.Many products include English labels, making them easy for short-term visitors to purchase.

Self-Care After Returning to Your Hotel

Handwashing, Face Washing, and Clothing Care

After being outdoors, wash your hands, gargle, and wash your face thoroughly.Lightly brushing off your outerwear before entering your hotel room can help prevent Kosa particles from spreading indoors.

Staying Healthy While Traveling

The Importance of Staying Hydrated

Dry throat conditions can weaken the body’s natural defenses.Drinking water regularly throughout the day can help reduce the risk of health issues during your trip.

The Relationship Between Kosa and PM2.5

Health Risks Based on Public Data

Trends Reported by the Ministry of the Environment and the Japan Meteorological Agency

According to data from the Ministry of the Environment, PM2.5 levels often rise when Kosa is present.This may increase the risk of respiratory and cardiovascular symptoms.

Why Even Short-Term Visitors Can Be Affected

A Medical Field Perspective

In home-visit medical settings, there are frequent consultations such as“I started coughing a few days after arriving in Japan,” or“My eyes suddenly became red.”

Even short-term exposure to a new environment can place stress on the body.

Which Symptoms Can Be Managed at a Drugstore — and Which Require Medical Care

Mild Symptoms That May Be Treated with Over-the-Counter Medication

Mild runny nose or eye irritation may improve with non-prescription medications.Using a smartphone translation app can help you explain your symptoms accurately to a pharmacist.

Symptoms That Should Be Evaluated by a Doctor or Clinic

Consider visiting a medical facility if you experience:

Persistent coughing or shortness of breath
Fever
Sudden worsening of symptoms

Signs That Require Emergency Care

A Checklist for Travelers

If breathing becomes difficult or conversation is hard to maintain, emergency medical care may be necessary.

If You Feel Unwell

Medical Care Options While Staying in Kyoto or Osaka

Language Barriers Faced by International Travelers

Many medical facilities in Japan primarily operate in Japanese.Difficulty communicating symptoms clearly can be a major source of anxiety for travelers.

Home Visit Medical Care

Receiving Medical Attention at Your Hotel

When you are not feeling well, there is no need to push yourself to travel to a clinic.Home-visit medical services allow you to receive care directly at your hotel, providing significant peace of mind during your stay.

Why Kyoto International Clinic Is Trusted by International Visitors

At Kyoto International Clinic, medical services are provided by doctors and nurses experienced in caring for international patients.During this season, consultations related to Kosa and allergy symptoms are common, and appropriate examinations and prescriptions can be provided even during your trip.

Common Medical Consultations Related to Kosa

First-Hand Clinical Data

Cough and sore throat
Allergic rhinitis
Eye inflammation

These symptoms are especially common in March.

Enjoy a Healthy Spring Trip to Kansai

Understand Kosa, Take Early Precautions, and Seek Care When Needed

Kosa is a natural phenomenon, but its impact can be minimized through proper precautions and early response.If you feel unwell, do not hesitate to consult Kyoto International Clinic.

Take care of your health and enjoy the beautiful spring season in Kyoto and Osaka to the fullest.