Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
The intervention effect on air-quality indices between otorhinolaryngology clinics with air-cleaner and without air-cleaner. The following air quality indices were measured: carbon dioxide (CO2), total volatile organic compounds (VOCs), particulate matter with diameter of <2.5 μm (PM2.5), and nitrogen dioxide (NO2).
