Which mask is really safe in AQI 500? Know expert opinion

By Samira Vishwas On Dec 20, 2025

The Air Quality Index (AQI) in Delhi-NCR has reached the dangerous level of 500 several times. This situation falls in the ‘most serious’ category, when fine particulate matter (PM2.5 and PM10) present in the air become a serious threat to health. At such times, wearing a mask while going out is considered mandatory, but the question is which mask can actually protect the lungs from pollution and which mask only works for show.

Severity of AQI 500

When AQI reaches 500, small pollutants in the air become so lethal that they can reach the lungs directly and affect the ability to breathe. This can cause problems like fatigue, cough, throat irritation, itching in the eyes and in severe cases, difficulty in breathing.

Which mask is most effective?

According to experts, just wearing a mask is not enough. The type, fit and filtration capacity of a mask determines how effective it is:

N95 / KN95 Mask
These masks block small pollutant particles like PM2.5 and PM10 by about 95%. When worn with proper fitting on the face, they prove to be helpful in protecting the lungs even in extreme pollution.

N99/N100 Mask
These masks have even higher filtration efficiency, meaning they block around 99% to 100% of small pollutant particles. These masks are considered the safest option in extreme pollution conditions.

surgical and cloth masks
These masks can help block larger dust particles and bacteria, but cannot filter out microscopic PM2.5. Therefore, in a situation like AQI 500, consider them only as additional protection, do not depend on them for main protection.

Things to keep in mind while wearing a mask

Ensure the correct size and fitting of the mask, so that air cannot enter through any space.

Do not use a dirty or wet mask, change it regularly.

It is safe for children, elderly and people with respiratory diseases to stay at home.

Use of masks is more effective when combined with air purifiers and proper ventilation.