Regulate Pollution or Land Use - Managing Toxic Air Contaminants in Southern California

A California air quality management district recently proposed to limit the location of potential receivers, in contrast with sources, of air toxics. The author argues that, although this particular proposal was later abandoned, it amounted to land use regulation. He also argues that such action usurps local control and is unwarranted

Impacts of Traffic Reductions Associated With COVID-19 on Southern California Air Quality

On 19 March 2020, California put in place Stay‐At‐Home orders to reduce the spread of SARS‐CoV‐2. As a result, decreases up to 50% in traffic occurred across the South Coast Air Basin (SoCAB). We report that, compared to the 19 March to 30 June period of the last 5 years, the 2020 concentrations of PM_(2.5) and NO_x showed an overall reduction across the basin. O₃ concentrations decreased in the western part of the basin and generally increased in the downwind areas. The NO_x decline in 2020 (approximately 27% basin‐wide) is in addition to ongoing declines over the last two decades (on average 4% less than the −6.8% per year afternoon NO₂ concentration decrease) and provides insight into how air quality may respond over the next few years of continued vehicular reductions. The modest changes in O₃ suggests additional mitigation will be necessary to comply with air quality standards

Sandia National Laboratories, California Air Quality Program : annual report.

The annual program report provides detailed information about all aspects of the SNL/CA Air Quality Program. It functions as supporting documentation to the SNL/CA Environmental Management System Program Manual. The program report describes the activities undertaken during the past year, and activities planned in future years to implement the Air Quality Program, one of six programs that supports environmental management at SNL/CA

Reduction of Toxic Air Contaminants (TACs) and particulate matter emissions from heavy-duty natural gas engines

Increasing urban pollution levels have driven the Federal and the local air control boards to impose stricter emissions regulations on heavy-duty engines earmarked for transit buses. This has made natural gas a promising fuel for reducing the emissions of oxides of nitrogen and predominantly particulate matter from heavy-duty transit buses. Recent research studies performed at WVU and elsewhere have showed that natural gas engines emit an order of magnitude lower PM emissions, on a mass basis, when compared to diesel engines without any exhaust aftertreatment devices. However, on a number basis the emissions from natural gas fueled buses were an order of magnitude higher than their diesel counterparts.;This project was initiated by Southern California Air Quality Management District to design and develop an exhaust aftertreatment device for retrofitting urban transit buses powered by heavy-duty natural gas engines. The exhaust aftertreatment device was developed for a Cummins Westport C8.3G+ natural gas engine. Exhaust samples were collected by operating the vehicle on the Central Business District cycle on a chassis dynamometer. Regulated emissions were continuously measured while non-regulated emissions samples were collected on different media from a full flow dilution tunnel. In addition, PM concentrations and size distributions were also measured. (Abstract shortened by UMI.)

Laser-induced thermal acoustics: simple accurate gas measurements

Laser-induced thermal acoustics (LITA), an optical four-wave mixing technique, has been used for sensitive measurement of the sound speed, thermal diffusivity, acoustic damping rate, and complex susceptibility of a gas. In LITA, laser-induced acoustic waves scatter laser light into a coherent, modulated signal beam. A simple expression accurately describes the signal. Atmospheric sound speeds accurate to 0.5% and transport properties accurate to 30% have been measured in a single shot without calibration. LITA spectra have been taken of weak spectral lines of NO2 in concentrations of less than 50 parts in 10^9. Signal reflectivities up to 10^4 are estimated

The Climate Gap: Inequalities in How Climate Change Hurts Americans & How to Close the Gap

By now, virtually all Americans concur that climate change is real, and could pose devastating consequences for our nation and our children. Equally real is the "Climate Gap" -- the sometimes hidden and often-unequal impact climate change will have on people of color and the poor in the United States. This report helps to document the Climate Gap, connecting the dots between research on heat waves, air quality, and other challenges associated with climate change. But we do more than point out an urgent problem; we also explore how we might best combine efforts to both solve climate change and close the Climate Gap -- including an appendix focused on California's global warming policy and a special accompanying analysis of the federal-level American Clean Energy Security Act

Ships, ports and particulate air pollution - an analysis of recent studies

The duration of use is usually significantly longer for marine vessels than for roadside vehicles. Therefore, these vessels are often powered by relatively old engines which may propagate air pollution. Also, the quality of fuel used for marine vessels is usually not comparable to the quality of fuels used in the automotive sector and therefore, port areas may exhibit a high degree of air pollution. In contrast to the multitude of studies that addressed outdoor air pollution due to road traffic, only little is known about ship-related air pollution. Therefore the present article aims to summarize recent studies that address air pollution, i.e. particulate matter exposure, due to marine vessels. It can be stated that the data in this area of research is still largely limited. Especially, knowledge on the different air pollutions in different sea areas is needed