Iswor Bajracharya

Internal-combustion engine (ICE) vehicles are major consumers of petroleum fuel and a major source of air pollution in the Kathmandu Valley. This study uses a bottom-up approach in the Low Emissions Analysis Platform (LEAP) to model vehicle fleet dynamics, project future energy demand and emissions for the period 2020–2040. Under the business-as-usual (BU) scenario, the stock of ICE vehicles grew rapidly, increasing cumulative petroleum demand to 44.8 PJ and CO2 emissions to 23.3 million metric tons by 2040. Although electric vehicle sales are growing at a compound annual growth rate of 38%, this growth is insufficient to reduce emissions significantly. Among the five scenarios studied, the Scrap Old Vehicle (SOV) and Improved Fuel Efficiency (IFE) scenarios reduced the energy demand and emissions only marginally. The Public Bus Penetration (PBP) scenario significantly curtailed cumulative gasoline demand by 40.7% and CO2 emissions by 6.57% by 2040 compared to the BA scenario. The Electric Vehicle Adoption (EVA) scenario reduced the ICE vehicle stock, cumulative energy demand, and CO2 emissions by 35.86%, 22.62%, and 26%, respectively, and required 494.5 MW of hydroelectricity by 2040. The combined (COM) scenario substantially reduced vehicle stock, cumulative energy demand, and CO2 emissions by 48.78%, 31.74%, and 32%, respectively, and projected 303 MW of hydroelectricity. This capacity is lower than the BU scenario capacity (313 MW), indicating that this scenario can avoid additional infrastructure development costs. These findings indicate the need for integrated, data-driven strategies to promote sustainable urban mobility.

Facemasks are widely used worldwide to prevent inhaling airborneparticles and viruses, especially after the outbreak of COVID-19. To assess theeffectiveness of various facemasks against PM₁₀ and PM_2.5,experiments with a mannequin head were conducted at 10 and 55 LPM airflowrates. A total of 38 masks, including 26 CMs, 7 SMs, and 5 N95 masks, weretested against PM₁₀ and PM_2.5 at 55 LPM airflow rate,while 18 masks, including 10 CMs, 6 SMs, and 2 N95 masks, were tested at 10 LPMairflow rate. The surface morphology of these facemasks was examined using asimple digital microscope of 0.3 M image sensor. SMs and N95 masks had smallerpore sizes and higher porosity, resulting in higher filtering efficiency. Incontrast, CMs had larger pore sizes and lower porosity, leading to poor filtering efficiency. Theaverage pore sizes of SMs and CMs were 70 μm and 160 μm, respectively, whiletheir porosities were 99 pores/mm² and 20 pores/mm², respectively. N95FFRshad an average pore size of 49 μm with a porosity of 88 pores/mm². The averagefiltering efficiency of facemasks followed the order N95 FFRs > SMs >CMs. The Prototype Cloth Masks (PTCMs) were stitched using cottonfabrics with adjustable ear straps, nose pins, and polypropylene (PP) fabric asthe filter. Their filtering efficiency was found to be nearlyequivalent to N95 masks and their performance did not deteriorate even afterfive washing and drying cycles. This facemask can help reduce particulateexposure, particularly in developing countries with high air pollution, such asthe Kathmandu Valley.

Inexpensive cloth masks are widely used to reduce particulate exposures, but their use became ubiquitous after the outbreak of COVID-19. A custom experimental setup (semiactive at 5.1m/s airflow rate) was fabricated to examine the efficiency of different types of commercial facemasks collected randomly from street vendors. The sample (N=27) including (n=16) cloth masks (CMs), (n=7) surgical masks (SMs), and (n=4) N95 filtering facepiece respirators (FFRs), of which SMs and N95 FFRs taken as a standard for efficiency comparison were all tested against ambient aerosols (PM_2.5 and PM₁₀μg/m³). The prototype cloth masks (PTCMs) (N=5) design was tailored, and their performance was assessed and compared with that of standard commercial masks. The filtering efficiency tested against ambient coarse particulates (PM₁₀) ranged from (5 to 34) for CMs with an average of 16, (37 to 46) for SMs with an average of 42, (59 to 72) for PTCMs with an average of 65, and (70 to 75) for N95 FFRs with an average of 71, whereas against fine particulates (PM_2.5), efficacy ranged from (4 to 29) for CMs with an average of 13, (34 to 44) for SMs with an average of 39, (53 to 68) for PTCMs with an average of 60, and (68 to 73) for N95 FFRs with an average of 70, respectively. The efficiency followed the order N95 FFRs>PTCMs>SMs>CMs showing poor exposure reduction potential in CMs and high exposure reduction potential in N95 FFRs and PTCMs. Amendment in existing CMs using eco-friendly cotton fabric with better facial adherence can protect human health from exposure to fine particulates μm and can reduce the risk of micro-plastic pollution caused by polypropylene (PP) facemasks.

Vehicular emissions have been playing a pivotal role in deteriorating air quality in many urban parts of Nepal causing adverse impacts upon the health of commuters and pedestrians attributed to severe respiratory diseases. Primary data such as the number of vehicles (N) were obtained using two-hour peak (8 am to 10 am) and two-hour nonpeak (1 pm to 3 pm) count, after which average annual vehicle kilometer (VKT) and fuel economy (F) required for emission load estimation were obtained from vehicle survey using the simple random sampling method, sampling size taken statistically under 5% margin of error. Secondary data in this study include emission factors and derived equations from a published article. The vehicular emission load of Bhaktapur Municipality were found to be 3,310 tons/year including CO₂, CO, NOx, HC, and PM₁₀ of which CO₂ accounts for 94.36% of total emissions followed by CO (4.39%), HC (0.72%), NOx (0.35%), and PM₁₀ (0.18%), respectively. Significant positive correlation was found (r = 0.92, ) between CO₂ and PM₁₀ (r = 0.87, ), between CO₂ and NOx (r = 0.90, ), between CO and HC (r = 0.74, ), and between NOx and PM₁₀, respectively. The scenario analysis shows that the introduction of electric vehicles at different rates within the municipality can reduce the emissions to a significant amount. Exponential growth in vehicular gaseous pollutants potent to jeopardize the environment and welfare can become inevitable in the future if clean energy technology is not promoted early.

Bottled water is generally considered safe for drinking. However, several studies have reported the substandard quality of bottled water. Physico-chemical assessment of ten different brands of bottled water distributed in Bhaktapur Municipality was carried out from January 2018 to March 2018. In total, one hundred bottled water samples consisting of ten different brands were collected randomly from various retail outlets. Eight selected physico-chemical and microbiological parameters were analysed following standard methods, and the results were compared with the Nepal Drinking Water Quality Standard (NDWQS) (2005). Out of one hundred samples, sixty-nine samples did not comply with the standard pH limit. Other physico-chemical parameters were found to comply with the standard though variations were observed in the concentrations among different brands. Microbial contamination was not found in any brands of the bottled water samples considered in this study. However, it is necessary to examine other contaminants such as heavy metals, minerals, and chemicals to know the overall quality of water. Moreover, the regulatory bodies are required to strictly monitor water processing companies for the maintenance of the quality of bottled water.