Results of the Indoor Air Quality Assessment in Selected Secondary Schools
- VernacularTitle:Ерөнхий боловсролын зарим сургуулийн дотоод орчны агаарын чанарын үнэлгээний дүн
- Author:
Myagmardorj Ch
1
;
Enkhjargal A
1
;
Enkhmunkh E
1
;
Altangerel B
1
;
Urantsetseg Ts
2
;
Battur L
1
;
Suvd B
3
;
Oyun-Erdene O
1
Author Information
1. National Center for Public Health
2. Mongolian University of Science and Technology
3. Ach Medical University
- Publication Type:Journal Article
- Keywords:
indoor air quality;
schools;
children;
PM2.5;
mould;
bacteria;
volatile organic compounds;
benzene;
Ulaanbaatar
- From:Mongolian Medical Sciences
2026;217(3):52-58
- CountryMongolia
- Language:Mongolian
-
Abstract:
Background:Indoor air quality in schools is an important environmental health concern because children
spend a substantial proportion of their time in classrooms and are particularly vulnerable to
air pollutants.
Objective:To assess common chemical, and biological pollutants in the indoor air of general education
schools in Ulaanbaatar.
Methods:A cross-sectional study was conducted from October 10, 2025, to March 1, 2026, in 16
purposively selected schools and 32 classrooms across six districts of Ulaanbaatar.
PM2.5, PM10, CO₂, and microclimatic parameters were monitored continuously for seven
days. Volatile organic compounds, formaldehyde, BTEX compounds, and radon were also
measured. Airborne microorganisms were assessed using 160 air samples, and 160 surface
swabs were collected. Results were compared with MNS 7106:2026, MNS 5484:2005, and
MNS 6410:2018 standards.
Results:The mean 24-hour concentrations of PM2.5 and PM10 were 25.2 and 36.1 µg/m³, respectively.
PM2.5 exceeded the permissible level during winter and in schools located in apartment
areas, whereas the mean PM10 concentration met the acceptable level. Total bacteria were
detected in all air samples, with a mean concentration of 1,733.25 CFU/m³. Mould and fungi
were detected in 56.3% of classrooms, and enteric bacteria were detected in 4.3% of surface
swabs. Radon levels remained below the permissible limit, and pathogenic bacteria were
not detected. Formaldehyde was detected in all samples, while total VOCs and toluene were
detected in 81.3%; their mean concentrations remained within acceptable levels. In one
classroom, the concentration of benzene was detected approximately 30 times higher the
permissible level.
Conclusion:Although some indoor air-quality indicators met the relevant standards, PM2.5,
total bacteria, mould and fungi, surface enteric bacteria, and benzene contamination require
improvement and may pose health risks to children. Regular ventilation, improved cleaning
and hygiene, proper maintenance of HEPA devices, and routine monitoring of particulate
matter, mould, and VOCs are needed.
- Full text:2026101821481052469MMS-2026-217(3)-52-58.pdf
