Background: Asthma is a heterogeneous disease, usually characterized by chronic airway inflammation. The air quality is influenced by locations of the air pollution sources, their performance capacity, the technology used, the composition of waste generated and geographical and climate conditions. In this study, a time-series analysis was conducted to estimate the association of short-term exposure to ambient air pollutants and hospitalization due to asthma in Ulaanbaatar. Objectives: We estimate the short-term associations between daily changes in ambient air pollutants and daily asthma in Ulaanbaatar, Mongolia. Methods: This is a time-series cross over study. All asthma hospital admission and air pollution data of 2008-2017 was used for this assessment. Data analyzed by using the program STATA-12. For testing the differences of the results were used appropriate non-parametric tests. Result: The daily mean of sulfur dioxide concentration was 35.22 mg/m 3 in the cold season, which was 7.57 times higher than the mean of the hot season. The mean annual PM 10 concentration was 182.73 μg/m 3. Most of the cases of asthma were among women, aged between 5-64 years old, registered during winter and spring. 3.8 people admitted to the hospital mostly on weekdays. In all Lag of SO 2 , in Lag of NO 2 , in all Lag of PM 10, in PM 2.5 and in all Lag except for Lag 2 of CO, Lag 0-2 of O 3 the incidence is likely to increase by 0.3%-6.1% per 10 units of pollutants. Conclusion: The air pollution especially PM 10, PM 2.5, and CO are the most harmful air pollutants to asthma in Ulaanbaatar. The correlation mainly between asthma admission cases with meteorological parameters is because of the cold winter condition.

Air and soil contamination in developing countries exacerbates due to poor management of waste collection and serves as a morbidity and mortality factor. This study aimed to conduct an assessment of soil pollution level in Ulaanbaatar and establish а correlation between microbial contamination and registered occurrences of contagious diarrheal diseases among children (0-5 years old). This is a cross-sectional study conducted in Ulaanbaatar in June-September of 2016. Samples of soil and contagious diarrheal disease morbidity data in 0-5-year-old children were used. Samples were taken from the sites three times, in July, August, and September. The data analysis was done in the SPSS-21 program and relevant parametric and non-parametric tests were used. The highest level microorganisms were found in the samples taken from sites near major markets and then in the samples from ger areas. The analysis of the samples revealed that 111.78 microorganisms exceed the standard level 1.1 times in summer. The Escherichia coli (E.Coli) and Proteus also contaminated the ground water. All diarrhea occasions in Ulaanbaatar were analyzed by seasons and months, the prevalence was peaking in August. A correlation was found with the soil E.Coli titers and infectious diarrheal disease children under five years old morbidity. The number of microorganisms in soil tends to increase in summer. Diarrheal disease infections among children under five increase most in summer and autumn and correlate with soil contamination with pathogenic microorganisms.