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Azad S, Ghandehari M. Emissions of nitrogen dioxide in the northeast U.S. during the 2020 COVID-19 lockdown. J Environ Manage 2022; 312:114902. [PMID: 35364514 PMCID: PMC9758611 DOI: 10.1016/j.jenvman.2022.114902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 03/08/2022] [Accepted: 03/13/2022] [Indexed: 06/14/2023]
Abstract
We have quantified the emissions of Nitrogen dioxide (NO2) in the Northeast megalopolis of the United States during the COVID-19 lockdown. The measurement of NO2 emission serves as the indicator for the emission of the group of nitrogen oxides (NOx). Approximately 56% of NO2 emissions in the US are from mobile sources, and the remainder is from stationary sources. Since 2002, clean air regulations have resulted in approximately 5% compound annual reduction of NOx emissions in the US (8.2% in the study area). Therefore, when studying the impact of sporadic events like an epidemic on emissions, it is necessary to account for the persistent reduction of emissions due to policy driven emission reduction measures. Using spaceborne sensors, ground monitors, National Emission Inventory data, and the US Motor Vehicle Emission Simulator, we quantified the reduction of total NOx emissions, distinguishing stationary sources from on-road mobile sources (trucks and automobiles). When considering total NOx emissions (stationary and mobile combined), we find that the pandemic restrictions resulted in 3.4% reduction of total NOx emissions in the study area in 2020. This is compared to (and in addition to) the expected 8.2% policy driven reduction of NOx emissions in 2020. This somewhat low reduction of emissions is because most stationary sources (factories, power plants, etc.) were operational during the pandemic. Truck traffic, a significant source of mobile emissions, also did not decline significantly (average 4.8% monthly truck traffic reduction in the study area between March and August 2020), as they were delivering goods during the lockdown. On the other hand, automobile traffic, responsible for 24% of total NOx emissions, dropped significantly, 52% in April, returning to near normal after 5 months. While the reduction of automobile traffic was significant, especially in the early months of the pandemic, its effect on emissions was relatively insignificant.
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Affiliation(s)
- Shams Azad
- New York University, Tandon School of Engineering, Department of Civil and Urban Engineering, 6 MetroTech Center, Brooklyn, NY, 11201, USA.
| | - Masoud Ghandehari
- New York University, Tandon School of Engineering, Department of Civil and Urban Engineering, 6 MetroTech Center, Brooklyn, NY, 11201, USA.
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Zare A, Stevanovic S, Jafari M, Verma P, Babaie M, Yang L, Rahman MM, Ristovski ZD, Brown RJ, Bodisco TA. Analysis of cold-start NO 2 and NOx emissions, and the NO 2/NOx ratio in a diesel engine powered with different diesel-biodiesel blends. Environ Pollut 2021; 290:118052. [PMID: 34479164 DOI: 10.1016/j.envpol.2021.118052] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/27/2021] [Accepted: 08/24/2021] [Indexed: 06/13/2023]
Abstract
In the transportation sector, the share of biofuels such as biodiesel is increasing and it is known that such fuels significantly affect NOx emissions. In addition to NOx emission from diesel engines, which is a significant challenge to vehicle manufacturers in the most recent emissions regulation (Euro 6.2), this study investigates NO2 which is a toxic emission that is currently unregulated but is a focus to be regulated in the next regulation (Euro 7). This manuscript studies how the increasing share of biofuels affects the NO2, NOx, and NO2/NOx ratio during cold-start (in which the after-treatment systems are not well-effective and mostly happens in urban areas). Using a turbocharged cummins diesel engine (with common-rail system) fueled with diesel and biofuel derived from coconut (10 and 20% blending ratio), this study divides the engine warm-up period into 7 stages and investigates official cold- and hot-operation periods in addition to some intermediate stages that are not defined as cold in the regulation and also cannot be considered as hot-operation. Engine coolant, lubricating oil and exhaust temperatures, injection timing, cylinder pressure, and rate of heat release data were used to explain the observed trends. Results showed that cold-operation NOx, NO2, and NO2/NOx ratio were 31-60%, 1.14-2.42 times, and 3-8% higher than the hot-operation, respectively. In most stages, NO2 and the NO2/NOx ratio with diesel had the lowest value and they increased with an increase of biofuel in the blend. An injection strategy change significantly shifted the in-cylinder pressure and heat release diagrams, aligned with the sudden NOx drop during the engine warm-up. The adverse effect of cold-operation on NOx emissions increased with increasing biofuel share.
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Affiliation(s)
- Ali Zare
- School of Engineering, Deakin University, VIC, 3216, Australia.
| | | | - Mohammad Jafari
- Biofuel Engine Research Facility, Queensland University of Technology (QUT), QLD, 4000, Australia; International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), QLD, 4000, Australia
| | - Puneet Verma
- Biofuel Engine Research Facility, Queensland University of Technology (QUT), QLD, 4000, Australia; International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), QLD, 4000, Australia
| | - Meisam Babaie
- School of Computing, Science and Engineering (CSE), University of Salford, Manchester M5 4WT, Salford, United Kingdom
| | - Liping Yang
- Institute of Power and Energy Engineering, Harbin Engineering University, No. 145-1, Nantong Street, Nangang District, Harbin, 150001, China
| | - M M Rahman
- School of Mechanical Aerospace and Automotive Engineering, Coventry University, Coventry, CV1 2JH, UK
| | - Zoran D Ristovski
- Biofuel Engine Research Facility, Queensland University of Technology (QUT), QLD, 4000, Australia; International Laboratory for Air Quality and Health, Queensland University of Technology (QUT), QLD, 4000, Australia
| | - Richard J Brown
- Biofuel Engine Research Facility, Queensland University of Technology (QUT), QLD, 4000, Australia
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Muhammad S, Long X, Salman M. COVID-19 pandemic and environmental pollution: A blessing in disguise? Sci Total Environ 2020; 728:138820. [PMID: 32334164 PMCID: PMC7169881 DOI: 10.1016/j.scitotenv.2020.138820] [Citation(s) in RCA: 295] [Impact Index Per Article: 73.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 04/14/2023]
Abstract
In late 2019, a novel infectious disease with human to human transmission (COVID-19) was identified in Wuhan China, which now has turned into a global pandemic. Countries all over the world have implemented some sort of lockdown to slow down its infection and mitigate it. Lockdown due to COVID-19 has drastic effects on social and economic fronts. However, this lockdown also has some positive effect on natural environment. Recent data released by NASA (National Aeronautics and Space Administration) and ESA (European Space Agency) indicates that pollution in some of the epicenters of COVID-19 such as Wuhan, Italy, Spain and USA etc. has reduced up to 30%. This study compiled the environmental data released by NASA and ESA before and after the coronavirus pandemic and discusses its impact on environmental quality.
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Affiliation(s)
- Sulaman Muhammad
- School of Management, Jiangsu University, Zhenjiang 212013, China.
| | - Xingle Long
- School of Management, Jiangsu University, Zhenjiang 212013, China.
| | - Muhammad Salman
- School of Management, Jiangsu University, Zhenjiang 212013, China
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