Modeling fuel consumption and emissions by taxis in Tabriz, Iran: uncertainty and sensitivity analyses.

Taxis pose a higher threat to global climate change and human health through air emissions. However, the evidence on this topic is scarce, especially, in developing countries. Therefore, this study conducted estimation of fuel consumption (FC) and emission inventories on Tabriz taxi fleet (TTF), Iran. A structured questionnaire to obtain operational data of TTF, municipality organizations, and literature review were used as data sources. Then modeling was used to estimate fuel consumption ratio (FCR), emission factors (EFs), annual FC, and emissions of TTF using uncertainty analysis. Also, the impact of COVID-19 pandemic period was considered on the studied parameters. The results showed that TTF have high FCRs of 18.68 L/100 km (95% CI=17.67-19.69 L/100 km), which are not affected by age or mileage of taxis, significantly. The estimated EFs for TTF are higher than Euro standards, but the differences are not significant. However, it is critical as can be an indication of inefficiency of periodic regulatory technical inspection tests for TTF. COVID-19 pandemic caused significant decrease in annual total FC and emissions (9.03-15.6%), but significant increase in EFs of per-passenger-kilometer traveled (47.9-57.3%). Annual vehicle-kilometer-traveled by TTF and the estimated EFs for gasoline-compressed natural gas bi-fueled TTF are the main influential parameters in the variability of annual FC and emission levels. More studies on sustainable FC and emissions mitigation strategies are needed for TTF.

Investigation in PO blending and compression ratio on engine performance and gas emissions including environmental health risk assessment and economic analysis.

Waste management and mitigation is the primary necessity across the globe. The daily use of plastic materials in different forms emergence the plastic pollutions, and it has been significantly increased during the COVID-19 pandemic. Thus, mitigation of waste plastics generation is one of the major challenges in the present situation. The present study addressed the conversion of waste plastics into value-added products such as liquid hydrocarbon fuels and their application in reducing greenhouse gas emissions. A comprehensive investigation has been performed on engine performance and combustion characteristics at various compression ratios and PO blending. The effect of liquid fuel blending with commercial diesel was investigated at three different compression ratios (15.1, 16.2, and 16.7) under various BMEP conditions. The results revealed that blending of liquid fuel produced from waste plastic can improve the BTE significantly, and the highest 35.77% of BTE was observed for 10% blending at 15.1 CR. While the lowest BSFC of 5.77 × 10-5 kg/kW-s was estimated for 20% PO blending at 16.7 CR under optimum BMEP (4.0 bar) conditions. The investigation of combustion parameters such as cylinder pressure, net heat release rate, rate of pressure rise, and cumulative heat release showed that it increases with the compression ratio from 15.1 to 16.7. At the same time, the emissions of CO, CO2, and unburnt hydrocarbon was decreased significantly. The economic analysis for the present lab-scale study estimated that approximately ₹12.17 ($0.15) profit per liter is possible in the 1st year, while the significant profit starts from the 2nd year onward, which is in the range of ₹59.78-₹84.48 ($0.75-$1.07) when the PO is blended with CD within the permissible limits as per the norms.

Tele-visits for GERD: "Ecofriendly, efficient and effective".

BACKGROUND AND AIM: Sars-CoV-19 pandemic necessitated a transition to telemedicine for many healthcare encounters. The environmental impact of this transition in gastroenterology (GI) combined with user experience has not been studied. METHODS: We conducted a retrospective cohort study of patients who underwent telemedicine visits (telephone and video) at a GI clinic at West Virginia University. Distance of patients' residence from clinic × 2 was calculated, and Environmental Protection Agency calculators utilized to calculate greenhouse gas (GHG) emissions that were avoided from tele-visits. Patients were reached by telephone and were asked questions to fill in a validated Telehealth Usability Questionnaire with Likert scales (1-7). Variables were also collected via chart review. RESULTS: A total of 81 video and 89 telephone visits were conducted for gastroesophageal reflux disease (GERD) between March 2020 and March 2021. A total of 111 patients were enrolled, with a response rate of 65.29%. Mean age was lower in the video visit cohort compared with the telephone visit cohort (43.45 ± 14.32 years vs 52.34 ± 17.46 years). Most patients had medications prescribed during the visit (79.3%), and a majority had laboratory testing orders placed (57.7%). We calculated a total distance of 8732 miles that the patients would have traveled if they were to present for in-person visits (including return trips). A total of 393.3 gallons of gasoline would have been required to transport these patients to and from the healthcare facility to their residence. A total of 3.5 metric tons of GHG's were saved by avoiding 393.3 gallons of gasoline for travel. In relatable terms, this is equivalent to burning more than 3500 pounds of coal. This averages to 31.5-kg GHG emissions and 3.54 gallons of gasoline saved per patient. CONCLUSION: Telemedicine for GERD resulted in significant environmental savings and was rated highly for access, satisfaction, and usability by patients. Telemedicine for GERD can be an excellent alternative to in-person visits.

Association of Virtual Care Expansion With Environmental Sustainability and Reduced Patient Costs During the COVID-19 Pandemic in Ontario, Canada.

Importance: There is a growing focus on environmental sustainability in health care. Objective: To estimate the environmental and patient-level financial benefits associated with the widespread adoption of virtual care during the COVID-19 pandemic. Design, Setting, and Participants: This population-based cross-sectional study obtained data from linked administrative databases in the universal health care system of Ontario, Canada, from March 2020 to December 2021. Participants included all people with a physician claim for at least 1 episode of virtual care. Exposures: Patients were stratified by age, socioeconomic status quintiles, Charlson Comorbidity Index, and area of residence (rural or urban). Main Outcomes and Measures: The primary outcomes were total travel distance and estimated travel-related carbon dioxide emissions avoided owing to virtual care visits. Different model assumptions were used to account for electric and hybrid vehicles and public transit use. The secondary outcomes were estimated patient costs (gasoline, parking, or public transit expenses) avoided. Results: During the 22-month study period, 10 146 843 patients (mean [SD] age, 44.1 [23.1] years; 5 536 611 women [54.6%]) had 63 758 914 physician virtual care visits. These visits were associated with avoidance of 3.2 billion km of travel distance and between 545 and 658 million kg of carbon dioxide emissions. Patients avoided an estimated total of $569 to $733 million (Canadian [US $465-$599 million]) in parking, public transit, and gasoline costs. Carbon dioxide emission avoidance and patient cost savings were more apparent in patients living in rural areas, those with higher comorbidity, and those who were older than 65 years. Conclusions and Relevance: Results of this study suggest that virtual care was associated with a large amount of carbon dioxide emissions avoided owing to reduced patient travel and with millions of dollars saved in parking, gasoline, or public transit costs. These benefits are likely to continue as virtual care is maintained as part of the health care system.

Impact of COVID-19 lockdown on carbonaceous aerosols in a polluted city: Composition characterization, source apportionment, influence factors of secondary formation.

Carbonaceous fractions throughout the normal period and lockdown period (LP) before and during COVID-19 outbreak were analyzed in a polluted city, Zhengzhou, China. During LP, fine particulate matters, elemental carbon (EC), and secondary organic aerosol (SOC) concentrations fell significantly (29%, 32% and 21%), whereas organic carbon (OC) only decreased by 4%. Furthermore, the mean OC/EC ratio increased (from 3.8 to 5.4) and the EC fractions declined dramatically, indicating a reduction in vehicle emission contribution. The fact that OC1-3, EC, and EC1 had good correlations suggested that OC1-3 emanated from primary emissions. OC4 was partly from secondary generation, and increased correlations of OC4 with OC1-3 during LP indicated a decrease in the share of SOC. SOC was more impacted by NO2 throughout the research phase, thereby the concentrations were lower during LP when NO2 levels were lower. SOC and relative humidity (RH) were found to be positively associated only when RH was below 80% and 60% during the normal period (NP) and LP, respectively. SOC, Coal combustion, gasoline vehicles, biomass burning, diesel vehicles were identified as major sources by the Positive Matrix Factorization (PMF) model. Contribution of SOC apportioned by PMF was 3.4 and 3.0 µg/m3, comparable to the calculated findings (3.8 and 3.0 µg/m3) during the two periods. During LP, contributions from gasoline vehicles dropped the most, from 47% to 37% and from 7.1 to 4.3 µg/m3, contribution of biomass burning and diesel vehicles fell by 3% (0.6 µg/m3) and 1% (0.4 µg/m3), and coal combustion concentrations remained nearly constant. The findings of this study highlight the immense importance of anthropogenic source reduction in carbonaceous component variations and SOC generation, and provide significant insight into the temporal variations and sources of carbonaceous fractions in polluted cities.

Long-Term In-Use NOx Emissions from London Buses with Retrofitted NOx Aftertreatment.

Buses constitute a significant source of air pollutant emissions in cities. In this study, we present real-world NOx emissions from 97 diesel-hybrid buses measured using on-board diagnostic systems over 44 months and 6.35 million km in London. Each bus had previously been retrofitted with a selective catalytic reduction (SCR) aftertreatment system to reduce emissions of nitrogen oxides (NOx). On average, parallel hybrid (PH) and series hybrid (SH) buses emitted 3.80 g of NOx/km [standard deviation (SD) of 1.02] and 2.37 g of NOx/km (SD of 0.51), respectively. The SCR systems reduced engine-out emissions by 79.8% (SD of 5.0) and 87.2% (SD of 2.9) for the PHs and SHs, respectively. Lower ambient temperatures (0-10 °C) increased NOx emissions of the PHs by 24.2% but decreased NOx emissions of the SHs by 27.9% compared to values found at more moderate temperatures (10-20 °C). To improve emissions inventories, we provide new distance-based NOx emissions factors for different ranges of ambient temperature. During the COVID-19 pandemic, the emissions benefits of reduced congestion were largely offset by more frequent route layovers leading to lower SCR temperatures and effectiveness. This study shows that continuous in-service measurements enable quantification of real-world vehicle emissions over a wide range of operations that complements conventional testing approaches.