Emissions Analysis of Southern California Metrolink Commuter Rail

1996 ◽  
Vol 1520 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Matthew J. Barth ◽  
Theodore Younglove ◽  
Ramakrishna R. Tadi
Keyword(s):  
Air Quality ◽  
Los Angeles ◽  
Southern California ◽  
Emissions Reduction ◽  
Diesel Locomotive ◽  
Passenger Vehicles ◽  
Modeling Process ◽  
Commuter Rail ◽  
Rail System ◽  
Emissions Modeling

The Southern California Regional Rail Authority began constructing a new commuter rail system called Metrolink in October 1992. When complete, the Metrolink system will form the nation's sixth largest commuter rail system and is expected to alleviate congestion and help obtain better air quality. To estimate the air quality impact, emissions of CO, HC, NOx, and PM associated with an automobile-only–based commute and a Metrolink-based commute from Riverside to Los Angeles are compared. Analysis of the Metrolink-based commuting scenario includes the emissions from the home-to-station automobile trip and the Metrolink diesel locomotive emissions. Essential data for the automobile emissions modeling process were obtained through a survey of Metrolink passengers and through remote emissions sensing of Metrolink passenger vehicles. Train emissions were estimated using emission rate data provided by recent diesel locomotive studies. Results indicated that at current ridership levels there is a reduction in total amount of all four pollutants combined through Metrolink commuting. On a pollutant-by-pollutant basis, it was estimated that the Metrolink commuting scenario reduces the emissions of CO and HC relative to the automobile-only commuting scenario; however, it increases the emissions of NOx and PM. The minimum amount of Metrolink ridership required to get a net emissions reduction from the system is predicted.

The Sunland Grizzly

2014 ◽  
Vol 91 (4) ◽  
pp. 56-63
Author(s):  
Josh Sides
Keyword(s):  
Los Angeles ◽  
Los Angeles County ◽  
Southern California ◽  
Grizzly Bear ◽  
Science And Art ◽  
Founding Director

In 1916, Cornelius Birket Johnson, a Los Angeles fruit farmer, killed the last known grizzly bear in Southern California and the second-to last confirmed grizzly bear in the entire state of California. Johnson was neither a sportsman nor a glory hound; he simply hunted down the animal that had been trampling through his orchard for three nights in a row, feasting on his grape harvest and leaving big enough tracks to make him worry for the safety of his wife and two young daughters. That Johnson’s quarry was a grizzly bear made his pastoral life in Big Tujunga Canyon suddenly very complicated. It also precipitated a quagmire involving a violent Scottish taxidermist, a noted California zoologist, Los Angeles museum administrators, and the pioneering mammalogist and Smithsonian curator Clinton Hart Merriam. As Frank S. Daggett, the founding director of the Los Angeles County Museum of History, Science and Art, wrote in the midst of the controversy: “I do not recollect ever meeting a case where scientists, crooks, and laymen were so inextricably mingled.” The extermination of a species, it turned out, could bring out the worst in people.

scholarly journals Examining the Economic and Environmental Impacts of COVID-19 Using Earth Observation Data

2020 ◽  
Vol 13 (1) ◽  
pp. 5
Author(s):  
William Straka ◽  
Shobha Kondragunta ◽  
Zigang Wei ◽  
Hai Zhang ◽  
Steven D. Miller ◽  
...  
Keyword(s):  
Air Quality ◽  
Los Angeles ◽  
Environmental Impacts ◽  
Demographic Data ◽  
The United States ◽  
Earth Observation ◽  
Observation Data ◽  
Washington Dc ◽  
Mobility Data ◽  
Earth Observation Data

The COVID-19 pandemic has infected almost 73 million people and is responsible for over 1.63 million fatalities worldwide since early December 2019, when it was first reported in Wuhan, China. In the early stages of the pandemic, social distancing measures, such as lockdown restrictions, were applied in a non-uniform way across the world to reduce the spread of the virus. While such restrictions contributed to flattening the curve in places like Italy, Germany, and South Korea, it plunged the economy in the United States to a level of recession not seen since WWII, while also improving air quality due to the reduced mobility. Using daily Earth observation data (Day/Night Band (DNB) from the National Oceanic and Atmospheric Administration Suomi-NPP and NO2 measurements from the TROPOspheric Monitoring Instrument TROPOMI) along with monthly averaged cell phone derived mobility data, we examined the economic and environmental impacts of lockdowns in Los Angeles, California; Chicago, Illinois; Washington DC from February to April 2020—encompassing the most profound shutdown measures taken in the U.S. The preliminary analysis revealed that the reduction in mobility involved two major observable impacts: (i) improved air quality (a reduction in NO2 and PM2.5 concentration), but (ii) reduced economic activity (a decrease in energy consumption as measured by the radiance from the DNB data) that impacted on gross domestic product, poverty levels, and the unemployment rate. With the continuing rise of COVID-19 cases and declining economic conditions, such knowledge can be combined with unemployment and demographic data to develop policies and strategies for the safe reopening of the economy while preserving our environment and protecting vulnerable populations susceptible to COVID-19 infection.

scholarly journals A revised position for the primary strand of the Pleistocene-Holocene San Andreas fault in southern California

2021 ◽  
Vol 7 (13) ◽  
pp. eaaz5691
Author(s):  
Kimberly Blisniuk ◽  
Katherine Scharer ◽  
Warren D. Sharp ◽  
Roland Burgmann ◽  
Colin Amos ◽  
...  
Keyword(s):  
Los Angeles ◽  
Southern California ◽  
San Andreas Fault ◽  
Slip Rate ◽  
Large Magnitude ◽  
Slip Rates ◽  
San Andreas ◽  
The Pacific ◽  
Large Earthquakes ◽  
Dependent Probability

The San Andreas fault has the highest calculated time-dependent probability for large-magnitude earthquakes in southern California. However, where the fault is multistranded east of the Los Angeles metropolitan area, it has been uncertain which strand has the fastest slip rate and, therefore, which has the highest probability of a destructive earthquake. Reconstruction of offset Pleistocene-Holocene landforms dated using the uranium-thorium soil carbonate and beryllium-10 surface exposure techniques indicates slip rates of 24.1 ± 3 millimeter per year for the San Andreas fault, with 21.6 ± 2 and 2.5 ± 1 millimeters per year for the Mission Creek and Banning strands, respectively. These data establish the Mission Creek strand as the primary fault bounding the Pacific and North American plates at this latitude and imply that 6 to 9 meters of elastic strain has accumulated along the fault since the most recent surface-rupturing earthquake, highlighting the potential for large earthquakes along this strand.

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