H2 in Antarctic firn air: Atmospheric reconstructions and implications for anthropogenic emissions

The atmospheric history of molecular hydrogen (H2) from 1852 to 2003 was reconstructed from measurements of firn air collected at Megadunes, Antarctica. The reconstruction shows that H2 levels in the southern hemisphere were roughly constant near 330 parts per billion (ppb; nmol H2 mol−1 air) during the mid to late 1800s. Over the twentieth century, H2 levels rose by about 70% to 550 ppb. The reconstruction shows good agreement with the H2 atmospheric history based on firn air measurements from the South Pole. The broad trends in atmospheric H2 over the twentieth century can be explained by increased methane oxidation and anthropogenic emissions. The H2 rise shows no evidence of deceleration during the last quarter of the twentieth century despite an expected reduction in automotive emissions following more stringent regulations. During the late twentieth century, atmospheric CO levels decreased due to a reduction in automotive emissions. It is surprising that atmospheric H2 did not respond similarly as automotive exhaust is thought to be the dominant source of anthropogenic H2. The monotonic late twentieth century rise in H2 levels is consistent with late twentieth-century flask air measurements from high southern latitudes. An additional unknown source of H2 is needed to explain twentieth-century trends in atmospheric H2 and to resolve the discrepancy between bottom-up and top-down estimates of the anthropogenic source term. The firn air–based atmospheric history of H2 provides a baseline from which to assess human impact on the H2 cycle over the last 150 y and validate models that will be used to project future trends in atmospheric composition as H2 becomes a more common energy source.

State-of-the-Art of Establishing Test Procedures for Real Driving Gaseous Emissions from Light- and Heavy-Duty Vehicles

Air pollution caused by vehicle emissions has raised serious public health concerns. Vehicle emissions generally depend on many factors, such as the nature of the vehicle, driving style, traffic conditions, emission control technologies, and operational conditions. Concerns about the certification cycles used by various regulatory authorities are growing due to the difference in emission during certification procedure and Real Driving Emissions (RDE). Under laboratory conditions, certification tests are performed in a ‘chassis dynamometer’ for light-duty vehicles (LDVs) and an ‘engine dynamometer’ for heavy-duty vehicles (HDVs). As a result, the test drive cycles used to measure the automotive emissions do not correctly reflect the vehicle’s real-world driving pattern. Consequently, the RDE regulation is being phased in to reduce the disparity between type approval and vehicle’s real-world emissions. According to this review, different variables such as traffic signals, driving dynamics, congestions, altitude, ambient temperature, and so on have a major influence on actual driving pollution. Aside from that, cold-start and hot-start have been shown to have an effect on on-road pollution. Contrary to common opinion, new technology such as start-stop systems boost automotive emissions rather than decreasing them owing to unfavourable conditions from the point of view of exhaust emissions and exhaust after-treatment systems. In addition, the driving dynamics are not represented in the current laboratory-based test procedures. As a result, it is critical to establish an on-road testing protocol to obtain a true representation of vehicular emissions and reduce emissions to a standard level. The incorporation of RDE clauses into certification procedures would have a positive impact on global air quality.

Effect of Automotive Emissions on Human Health

Vehicular emissions are creating major problems to the urban residents following by health impacts. According to WHO, Gwalior ranks second in the most air polluted city in India. The study is carried out to estimate automotive emissions, health effects, and estimation of health damage cost. Seven major junctions have been identified in which the highest peak hour PCU is observed at Bada (13,859) followed by Railway Station and Gole ka Mandir which accounts for through as well as destined traffic of whole city. According to the BS Norms, reduction in emission is calculated for different a pollutant, which shows 40.02Kg of CO concentration in BS III which reduces to 20.06 Kg in BSVI. Lastly, health damage cost for different Norms has been calculated which shows Rs.4938.54 for BSIII & Rs.467.33 for BS VI under low cost scenario. Health damage cost under high cost scenario for BS III shares Rs.68436.63 and Rs.6424.64 for BSVI. Introduction of cleaner fuels, maintenance of vehicles, and regular inspection of vehicles should be done to improve the quality of life of people.

Automotive Emissions Regulations and Exhaust Aftertreatment Systems

The objective of this book is to present a fundamental development of the science and engineering underlying the design of exhaust aftertreatment systems for automotive internal combustion engines. No pre-requisite knowledge of the field is required: our objective is to acquaint the reader, whom we expect to be new to the field of emissions control, with the underlying principles, control methods, common problems, and fuel effects on catalytic exhaust aftertreatment devices. We do this in hope that they can better understand the previous and current generations of emissions control, and improve upon them. This book is designed for the engineer, researcher, designer, student, or any combination of those, who is concerned with the control of automotive exhaust emissions. It includes discussion of theory and fundamentals applicable to hardware development.

The Development of Air Pollution in Mexico City

The present essay documents changes to both objects of inquiry and the meaning of the epistemological concept of air pollution and it explains the processes that produced them. Smog as a result of production processes and the use of the automobile was not a concern for researchers and government managers in Mexico City, who were used to the dust storms resulting from the desiccation of the great Texcoco Lake during much of the 20th century, until the most industrialized nations of the West and the World Health Organization (WHO), alongside other international bodies such as the Organization for European Economic Cooperation (OEEC), reframed what was understood as air pollution, between the end of the 1960s and the beginning of the 1970s. Concerns about dust storms were displaced by concerns about factory and automotive emissions that contained new dangers—invisible hazards, just then being estimated, which altered what was understood or considered air pollution and gave rise to the quantification of particulate matter (which was then known as suspended dust particles) and new practices such as atmospheric monitoring. This essay concludes that what is understood as air pollution is situated; its meaning is not finite but simply evolves with time and with the rise of new global risks and concerns.

Stable carbon δ13C analysis of automotive particulate matter emissions under controlled conditions

<p>Excessive automotive engine exhaust emissions of gases and particulate matter (PM) pose a threat to public health and urban air quality. In an effort to reduce automotive emissions modern cars use a variety of engine modifications, catalytic systems and filters which in turn alter the isotope ratio of carbonaceous particles (isotope fractionation effect). Diesel engines are of particular interest due to higher production of particulates (soot) in comparison to gasoline engines [1].</p><p>The aim of this work was to examine particulate matter δ<sup>13</sup>C variation in automotive emissions using stable carbon isotope ratio measurements. Emission experiments were performed in dynamometer laboratory using four light passenger vehicles with differing liquid fuels - diesel, diesel with additives, 92 RON and 95 RON. Vehicles were tested with varying engine power and using simulated transient cycles in urban and rural areas. Engine exhaust particulate matter was collected on quartz filters. Later, isotope ratio δ<sup>13</sup>C values of fuel and exhaust carbonaceous particulates were measured using IRMS. δ<sup>13</sup>C values were then compared and level of isotope fractionation determined.</p><p>The obtained results show particulate matter δ<sup>13</sup>C values ranging from -28.8 ‰ to -27.2 ‰ during separate driving modes. Isotope fractionation Δ (particulates-fuel) values varied between 1.8 ‰ and 3.5 ‰. It was determined that δ<sup>13</sup>C values of automotive emissions depend on the type of fuel used, applied engine power, driving modes (urban, rural) and can be used to characterize automotive carbonaceous particle emissions.</p><p> </p><p>[1]             M. V. Twigg, “Progress and future challenges in controlling automotive exhaust gas emissions,” <em>Appl. Catal. B Environ</em>., 2007.</p>