Quantifying effects of meteorological parameters on air pollution in Kathmandu valley through regression models.

Most studies on air pollution have focused on source apportionment aspect but very few have considered meteorological factors responsible for variation in air pollution levels including studies in Nepal. Consequently, the effects of meteorological parameters including effects of seasonality and lag effects are investigated and quantified for Kathmandu valley, Nepal. Daily temporal data of air pollution for 2017-early 2020 monitored by the Department of Environment and US Embassy, Kathmandu, Nepal, and meteorological data monitored by the Department of Hydrology and Meteorology, Kathmandu, Nepal, are used. Regression models namely exponential, Box-Cox transformed and Gamma generalized linear models are used to quantify the effects supported by regression diagnostics. Results depict high proportions of observed air pollution variations (79-85%) explained by the fitted models with varied effects of meteorological parameters. Around 5% reduction in PM10 (96% CI: 0.034-0.069) and PM1 (95% CI: .0.029-0.063) levels per 1 °C increase in average temperature and significant increase in surface O3 level (0.177, 95% CI: 0.126-0.228 Box-Cox transformed value) per 1 °C increase in average temperature are detected. Similarly, around 0.7% (95% CI: 0.1-1.3) and 2% (96% CI:1.3-2.5) decrease in PM1 and PM10, respectively per 1% increase in relative humidity, 0.032 (95% CI: 0.024-0.040) decrease in transformed value of PM2.5 per 1 mm increase in rainfall, and 7.3% (95% CI: 1.3-15.9) decrease in PM10 per 1 m/s increase in wind speed are also detected. In conclusion, meteorological conditions are found significant contributing factors in determining air pollution levels in Kathmandu valley. On the long run, atmospheric conditions can play vital roles in air pollution situation shifts mainly due to climate change characterized by changes in meteorological values.

Effects of Climatic Factors on Diarrheal Diseases among Children below 5 Years of Age at National and Subnational Levels in Nepal: An Ecological Study.

Introduction: The incidence of diarrhea, a leading cause of morbidity and mortality in low-income countries such as Nepal, is temperature-sensitive, suggesting it could be associated with climate change. With climate change fueled increases in the mean and variability of temperature and precipitation, the incidence of water and food-borne diseases are increasing, particularly in sub-Saharan Africa and South Asia. This national-level ecological study was undertaken to provide evidence linking weather and climate with diarrhea incidence in Nepal. Method: We analyzed monthly diarrheal disease count and meteorological data from all districts, spanning 15 eco-development regions of Nepal. Meteorological data and monthly data on diarrheal disease were sourced, respectively, from the Department of Hydrology and Meteorology and Health Management Information System (HMIS) of the Government of Nepal for the period from 2002 to 2014. Time-series log-linear regression models assessed the relationship between maximum temperature, minimum temperature, rainfall, relative humidity, and diarrhea burden. Predictors with p-values < 0.25 were retained in the fitted models. Results: Overall, diarrheal disease incidence in Nepal significantly increased with 1 °C increase in mean temperature (4.4%; 95% CI: 3.95, 4.85) and 1 cm increase in rainfall (0.28%; 95% CI: 0.15, 0.41). Seasonal variation of diarrheal incidence was prominent at the national level (11.63% rise in diarrheal cases in summer (95% CI: 4.17, 19.61) and 14.5% decrease in spring (95% CI: −18.81, −10.02) compared to winter season). Moreover, the effects of temperature and rainfall were highest in the mountain region compared to other ecological regions of Nepal. Conclusion: Our study provides empirical evidence linking weather factors and diarrheal disease burden in Nepal. This evidence suggests that additional climate change could increase diarrheal disease incidence across the nation. Mountainous regions are more sensitive to climate variability and consequently the burden of diarrheal diseases. These findings can be utilized to allocate necessary resources and envision a weather-based early warning system for the prevention and control of diarrheal diseases in Nepal.

Indoor air pollution from biomass fuels and respiratory health of the exposed population in Nepalese households.

A cross-sectional assessment of indoor air quality in Nepal and its health effects revealed that solid biomass fuels (animal dung, crop residue, and wood) were the main sources of indoor air pollution affecting health. The average smoke level (PM10) in kitchens using biomass fuels was about three times higher than that in those using cleaner fuels (kerosene, LPG, and biogas). Respondents in 98 randomly selected households included 168 who cooked daily meals, of whom 94% were disadvantaged women. Biomass smoke caused significantly more respiratory disorders than did cleaner fuels. Categorized data analysis demonstrated significant associations between biomass smoke pollution and respiratory symptoms such as cough; phlegm; breathlessness; wheezing; and chronic respiratory diseases such as COPD and asthma. The prevalences of respiratory illnesses and symptoms were considerably higher in those living in mud and brick houses compared with concrete houses. Prevalences were also higher in those living on hills and in rural areas compared with flatland and urban areas.