Air Quality Guide

Fine Dust Guide

Understand fine dust and ultrafine particulate matter: PM10 and PM2.5 differences, health effects, air quality standards, and protection tips.

Good

Normal activity

Moderate

Sensitive groups should take caution

Unhealthy

Limit outdoor activity, wear a mask

Grade quick table

GradePM10PM2.5Health impact
Good0-540-12Normal activity
Moderate55-15412.1-35.4Sensitive groups should take caution
Unhealthy155-25435.5-55.4Limit outdoor activity, wear a mask
Very Unhealthy255+55.5+Avoid outdoor activity

Topic 01

What Is Fine Dust?

Fine dust refers to tiny airborne particulate matter. It is categorized by size: PM10 (particles 10 micrometers or smaller in diameter) and PM2.5 (particles 2.5 micrometers or smaller, also called ultrafine dust). These particles are 1/20 to 1/30 the width of a human hair and invisible to the naked eye.

Topic 02

Health Effects

Short-term exposure: Coughing, sneezing, eye irritation, sore throat. Asthma and rhinitis patients may experience worsened symptoms. Long-term exposure: Reduced lung function, increased cardiovascular disease risk, increased lung cancer risk. The WHO classifies particulate matter as a Group 1 carcinogen. Sensitive groups: The elderly, children, pregnant women, and those with respiratory or cardiovascular conditions should take precautions even at moderate levels.

Topic 03

Fine Dust vs. Pollen

Pollen and fine dust are different substances, but when both are elevated simultaneously, symptoms can be significantly worse. Pollen grains can bind to fine dust particles, allowing them to penetrate deeper into the airways. This is why Achoo shows both pollen and air quality data together, helping you make informed decisions about outdoor activity.

Topic 04

Prevention Tips

Wear an N95 or FFP2 mask (filters at least 94% of particles). Run a HEPA air purifier indoors. Avoid ventilating when air quality is poor. Wash face and rinse nasal passages after being outside. Drink plenty of water to keep airways moist. Avoid intense outdoor exercise (higher breathing rate means more particle inhalation).

Topic 05

Data Sources

Achoo uses air quality data from Open-Meteo, which draws on the European CAMS (Copernicus Atmosphere Monitoring Service) model. Data is updated hourly and covers locations worldwide. For users in Korea, PM data from AirKorea (Korean Ministry of Environment) is also used.