Introduction: During this pandemic, overcrowding in classroom caused by a lack of educational facilities and poor indoor air quality are the main causes of respiratory diseases among children and adolescents. Therefore, it is essential to measure and assess the indoor air quality where children spend extended periods of time such as school. Materials and methods: This study covered four schools with old buildings and four schools with new buildings in Bayanzurkh, Sukhbaatar, Khan-Uul, Chingeltei district of Ulaanbaatar. We collected PM10 and PM2.5, carbon dioxide, air temperature, humidity, and microbiological count from chosen classrooms and compared to the MNS4585:2016 standard. SPSS-24 was used to do statistical analysis on the information gathered during the evaluation. Results and Discussion: The 24-hour average PM2.5 concentration was 64.3 (95% CI: 64.1-64.5) mcg/m3, which was 4.3 times higher than the WHO guideline value and 1.3 times higher than the MNS4585:2016 standard. The 24-hour average PM10 concentration was 85.3 (95 % CI: 85.1-85.6) mcg/m3, which is 1.9 times higher than WHO guideline value. In older school buildings, the 24-hour average PM2.5 concentration was 5.6 times higher than the WHO guideline value and 1.7 times higher than the MNS4585:2016; the average PM10 concentration was 2.8 times higher than the WHO guideline value and 1.3 times higher than the MNS4585:2016. The air temperature and carbon dioxide concentration in classroom was met the MNS4585: 2016. The average relative humidity of all schools is 24.2±6.5%, which is 14-16% lower than the MNS4585: 2016. Conclusion The indoor air quality of the school in new and old buildings was similar poor, therefore a variety of steps are needed to improve it.

Research of function of vitamin D on immune system has been studying since the study revealed that vitamin D receptor is expressed on the surface of the immune cells. 1,2-dihydroxyvitamin D3 [1,25(OH)2D], physiologically active form, can be generated through hydroxylation of 25-hydroxyvitamin D3 [25(OH)D], inactive form of vitamin D, in a liver, connecting with specific VDR make biological action. Vitamin D make different biological actions depends on connecting with different immunological cells. Some studies indicated that Vitamin D plays pivotal role in antibacterial innate immune responses through regulating reaction of the main cells as macrophages and dendritic cells. Moreover, calcitriol, the active form of vitamin D, is connected with VDRE, modulates the innate immune response through directly inducing expression of catelicithin and β-defensin as antimicrobial peptides, reducing secretion of IL-1b, IL-6, TNF-a, RANKL, COX-2 as proinflammatory cytokines and increasing production of IL-10, an anti-inflammatory cytokine. Vitamin D plays in proliferation and differentiation of T and B cells and regulates the activities of over 500 genes. Vitamin D differently impacts on per se stages of T cells’ proliferation. Vitamin D indirectly mitigates the differentiation from immature B cells to plasma B cells while it directly impacts on regulation of overloaded production of antibodies in plasma B cells. In conclusion, vitamin D modulates the innate- and adaptive immune response through regulation on activation of APCells, proliferation and differentiation of immune cells, secretion of some antibacterial peptides.

Introduction: Air pollution has become one of the major problems in socio-economic and health issues in Mongolia. Among the various hazards of particulate matter (PM) pollutants, microorganisms in PM2.5 and PM10 are thought to be responsible for various allergies and for the spread of respiratory diseases. Recent studies have shown that PM2.5 particles can cause chronic heart failure, heart arrhythmias, and strokes, as well as lung damage, cirrhosis, inflammation, cancer, cardiovascular disease, and metabolic disorders. Furthermore, some studies have concluded that PM2.5 particles in the environment are a risk factor for gastrointestinal, liver, colon, and lung cancer as well as it affects the growth and metastasis of various cancer cells caused by other factors. In our country, the health effects of air pollution and the relationship between the pathogenesis of cancer research are scarce. Therefore, the study of the effects of PM2.5 particles on cancer cell proliferation, migration (metastasis) can provide a significant role for cancer treatment, diagnosis, and prevention. Purpose: Determining the effects of PM2.5 particles on cancer cell proliferation, migration (metastasis) in in-vitro Material and Methods: A human liver cancer cell line (HepG2), human gastric cancer cell line (AGS) were obtained from the central scientific research laboratory in the Institute of medical sciences. HepG2, AGS cells were seeded at a concentration of 1*105 cells/mL in a culture flask and cultured in RPMI-1640 medium supplemented with 10% FBS, 1% antibiotic mix (penicillin, streptomycin) in a humidified atmosphere of 5% CO2 at 37 °C. The cytotoxic effect of PM 2.5 in AGS, HepG2 cells were evaluated by MTT, CCK8 assays. AGS, HepG2 cells were incubated in 96 well plates for 24h then treated with different concentrations (0, 5, 10, 25, 50 and 100 μg ) of Bayankhoshuu, Buhiin urguu, and Zaisan samples for 24h, respectively. Results: Concentrations of 10, 25, and 50 μg/ml of samples collected from the Bukhiin urguu and Zaisan in March increased HepG2 cell growth, while doses of 25, 50 μg/ml of samples collected from Bayankhoshuu in March and December increased HepG2 cell growth. Therefore, concentrations of 25 and 50 μg/ml of samples collected from Bayankhoshuu in March increased AGS cell growth, while concentrations of 25, 100 and μg/ml of samples collected in December increased AGS cell growth. However, no cytotoxic effect was observed in the sample collected from Zaisan in March, whereas the PM2.5 sample enhanced AGS cell growth in dose dependent manner in December.(p <0.05) Conclusion High levels of heavy metals were detected in samples collected in December from Bayankhoshuu, Bukhiin urguu and Zaisan of Ulaanbaatar. Concentration of 25 μg/ml of samples collected from the Bukhiin urguu and Zaisan in March increased HepG2 cell growth. Concentrations of 25 μg/ml of PM2.5 collected from three regions around Ulaanbaatar increased HepG2 and AGS cell migration.