Analysis of Motorcycle Exhaust Regular Testing Data—A Case Study of Taipei City

Abstract

In Taiwan, a continuous increase in the number of motorcycles has made exhaust pollution one of the major emission sources of air pollutants. The regular testing program carried out by the Republic of China Environmental Protection Agency was designed to reduce air pollutant emissions by enhancing maintenance and repair. During the execution period, abundant testing results were accumulated to discuss pollutant emissions from motorcycles. Exhaust testing data of motorcycles in Taipei City from 1996 to 2005 were chosen as the basic data to survey changes in motorcycle exhaust. Effects of motorcycle age and mileage on exhaust pollution were studied. The introduction of advanced emission standards enhances the elimination of high-emitting motorcycles. The testing data indicate that the testing rate rose from approximately 50 to 70% and the failure rate changed from approximately 15 to 10%. The operation cycles of two-stroke motorcycles make them high-emitting vehicles. Concentrations of carbon monoxide and hydrocarbons are higher in two-stroke motorcycle exhaust than that in four-stroke motorcycles. In contrast, the concentration of carbon dioxide produced from complete oxidation processes is lower in exhaust from two-stroke motorcycles. Therefore, failure rates of two-stroke motorcycles are higher than those of four-stroke motorcycles and were also observed to deactivate more easily. On the basis of analytical results of testing data, we found that failure rates show a gradually increasing trend for motorcycles older than 3 yr or used for mileages greater than 10,000 km, and failure rates are highly correlated to the age/mileage of motorcycles. We reason that the accumulation of age or mileage means accumulating usage time of engines and emission control systems. Concentrations of pollutant emissions would increase because of engine wear and emission control system deactivation. After discussing changes of failure rates and pollutant emissions, some suggestions are proposed to improve the testing rate and effectiveness of regular testing.     

Air Quality Criteria—Toxicological Appraisal for Oxidants,Nitrogen Oxides,and Hydrocarbons

The ultimate aim of toxicological studies is to determine the effects of pollutants on the health and welfare of human beings. To get this it is essential to conduct animal studies to evaluate the potential toxicity of different pollutants. Toxicological appraisal of the photochemical oxidant type of air pollution shows: (1) The effects are primarily on the lungs and the senses. (2) There is impairment of pulmonary function in humans at concentrations found in polluted air. (3) Both ozone and nitrogen dioxide tend to oxidize in animals the lung tissue for a time. This process creates agents which have the potential for cross-linking structural proteins, and this process initiates inflammation which accelerates cell turnover rates. Both crosslinking and cell turnover rates are factors in aging, which may thus be accelerated by years of repeated exposure to oxidants. (4) Long-term exposure to low levels of nitrogen dioxide can produce pre-emphasematous lesions in the lungs of rats and mice. Studies with other species are needed. (5) Ozone, nitrogen dioxide, and dilute irradiated car exhausts increase susceptibility to respiratory infection.

The constant search for more sophisticated and sensitive techniques to detect subtle changes indicative of pre-disease conditions should not be relaxed. Such techniques will provide chronic disease predictors of great relevance as air quality criteria.     

Maximum Ground-Level Concentrations with Downwash—Analysis

ABSTRACT

Equations derived previously for critical downwind distance x , wind speed u , and plume rise z , the values that produce maximum ground-level concentrations (MGLC) X_c under downwash conditions, have been solved. Tables of %_c, x_c, u_c, and z_c, and graphs of the relationships among u_c and z_c for a range of stack heights h_s, and building heights h_b, are presented. Results for two types of sources— a turbine and a reciprocating engine—are discussed. Some comparisons are made to the U.S. Environmental Protection Agency's (EPA) SCREEN3 model.     

Modeling Sorbent Injection for Mercury Control in Baghouse Filters: I—Model Development and Sensitivity Analysis

Abstract

A two-stage mathematical model for Hg removal using powdered activated carbon injection upstream of a bag-house filter was developed, with the first stage accounting for removal in the ductwork and the second stage accounting for additional removal caused by the retention of carbon particles on the filter. The model shows that removal in the ductwork is minimal, and the additional carbon detention time from the entrapment of the carbon particles in the fabric filter enhances the Hg removal from the gas phase. A sensitivity analysis on the model shows that Hg removal is dependent on the isotherm parameters, the carbon pore radius and tortuosity, the C/Hg ratio, and the carbon particle radius.     

Effectiveness in the Use of Natural Gas for the Reduction of Atmospheric Emissions: Case Study—Industrial Sector in the Metropolitan Region of Santiago,Chile

Abstract

The purpose of this investigation was to quantify the potential of natural gas to reduce emissions from stationary combustion sources by analyzing the case study of the metropolitan region of Santiago, Chile. For such purposes, referential base scenarios have been defined that represent with and without natural gas settings. The method to be applied is an emission estimate based on emission factors. The results for this case study reveal that stationary combustion sources that replaced their fuel reduced particulate matter (PM) emissions by 61%, sulfur oxides (SO_x) by 91%, nitrogen oxides (NO_x) by 40%, and volatile organic compounds (VOC) by 10%. Carbon mon-oxide (CO) emissions were reduced by 1%. As a result of this emission reduction, in addition to reductions caused by other factors, such as a shift to cleaner fuels other than natural gas, technological improvements, and sources which are not operative, emission reduction goals set forth by the environmental authorities were broadly exceeded.     

N-alkane studies in the troposphere—II: Gas and particulate concentrations in Indian Ocean air

Westerly winds arriving at the Australian Clean Air Baseline Station Cape Grim at the North Western tip of Tasmania have exceedingly long trajectories over the Indian Ocean. In these air masses we found the n-alkanes C₉-C₂₈ to be always present in the gas phase and also in the aerosols. In aerosols we also measured total organic matter and its general composition. All these concentrations agree fairly well with our earlier data in marine air over the North Atlantic Ocean. Calculations of the life time of the gas phase n-alkanes due to reaction with OH radicals lead to the conclusion that these n-alkanes must be of oceanic origin in Indian Ocean air and — to a large extent — also in the North Atlantic air. The same conclusion is reached for the organic component in aerosols. Water Analyses show that the n-alkanes C₉-C₂₈ seem to be normal constituents of the oceans.     

n-Alkane studies in the troposphere—I. Gas and particulate concentrations in north Atlantic air

Simultaneous measurements of gas phase and paniculate concentrations of C₉–C₂₈n-alkanes in clean air at the west coast of Ireland are reported. All n-alkanes were regularly present with gas phase concentrations between about 10 and 20 × 10⁻⁹ g m⁻³ STP, showing no systematic decrease above C₁₃. Continental air showed higher concentrations. The fraction of alkanes attached to aerosol particles increases from less than 1% at low C-numbers to several per cent at high C-numbers. The carbon preference index is generally close to 1.0; seawater samples from that area exhibit similar distributions of n-alkanes as the gas phase.     

Gas chromatography�Cmass spectrometry for metabolite profiling of Japanese medaka (Oryzias latipes) juveniles exposed to malathion

Purpose

We evaluate malathion toxicity to Japanese medaka (Oryzias latipes) juveniles by using a mass spectrometry combined with gas chromatography (GC/MS) metabolomics approach.

Methods

Medaka were exposed to low (L) and high (H) concentrations (nominally 20 and 2,000 ??g/L, respectively) of water-borne malathion. Metabolites were extracted from the fish, derivatized, and analyzed by GC/MS. Identified metabolites were subjected to one-way analysis of variance and principal component analysis (PCA). We examined the variations in the amounts of the metabolites during the exposure period.

Results and discussion

At 24 h, control, L, and H groups were separated along PC1, suggesting that the effects of malathion depended on exposure concentration. The PCA results at 96 h suggest that the metabolite profiles variations of the L and H groups differed, and thus that the effects of malathion in groups differed. At 24 h, the amounts of amino acids in both exposed groups were lower than the control group amounts, perhaps owing to accelerated protein synthesis. At 96 h, the amounts of almost all the amino acids increased in the L group but decreased in the H group relative to the control group amounts, suggesting the proteolysis occurred in the L group while protein synthesis continued in the H group, that the high malathion exposure affected the fish. In addition, at 96 h, gluconeogenesis may have been induced in the L group but not in H group.

Conclusions

Malathion exposure may have altered the balance between protein synthesis and degradation and induced gluconeogenesis in medaka. Our results suggest that metabolomics will be useful for comprehensive evaluation of toxicity.     

Visibility-pollutant relationships in Southern Arizona—I. Analysis of the historical data base

A multivariate statistical analysis of the pollutant and meteorological data collected in and near Tucson, Arizona during the period 1974–1978 is presented. These data are analyzed for trends and correlations between visibility (as reported by National Weather Service), light scattering coefficient (from the integrating nephelometer), and atmospheric loadings of various pollutants. Significant findings include (1) evidence of regional sulfate loading, uniformly distributed in urban and nonurban areas and (2) significant correlation of sulfate to light scattering coefficient, but little correlation to NWS visibility. As a result of this analysis, a field study of size and chemical distribution of atmospheric aerosols in this region was undertaken.     

Boiler Briquette Coal versus Raw Coal: Part II—Energy,Greenhouse Gas,and Air Quality Implications

ABSTRACT

The objective of this paper is to conduct an integrated analysis of the energy, greenhouse gas, and air quality impacts of a new type of boiler briquette coal (BB-coal) in contrast to those of the raw coal from which the BB-coal was formulated (R-coal). The analysis is based on the source emissions data and other relevant data collected in the present study and employs approaches including the construction of carbon, energy, and sulfur balances. The results show that replacing R-coal with BB-coal as the fuel for boilers such as the one tested would have multiple benefits, including a 37% increase in boiler thermal efficiency, a 25% reduction in fuel demand, a 26% reduction in CO₂ emission, a 17% reduction in CO emission, a 63% reduction in SO₂ emission, a 97% reduction in fly ash and fly ash carbon emission, a 22% reduction in PM_2.5 mass emission, and a 30% reduction in total emission of five toxic hazardous air pollutant (HAP) metals contained in PM₁₀. These benefits can be achieved with no changes in boiler hardware and with a relatively small amount of tradeoffs: a 30% increase in PM₁₀ mass emission and a 9–16% increase in fuel cost.     

Analysis of mobile source air toxics (MSATs)—Near-road VOC and carbonyl concentrations

Exposures to mobile source air toxics (MSATs) have been associated with numerous adverse health effects. While thousands of air toxic compounds are emitted from mobile sources, members of a subset of compounds are considered high priority due to their significant contribution to cancer and noncancer health risks and the contribution of mobile sources to total exposure as evaluated by the U.S. Environmental Protection Agency (EPA) National-Scale Air Toxics Assessments (NATA). These pollutants include benzene, 1,3-butadiene, ethylbenzene, acrolein, acetaldehyde, formaldehyde, naphthalene, polycyclic organic matter, and diesel particulate matter/organic gases. This study provided year-long trends of benzene, 1,3-butadiene, acrolein, acetaldehyde, and formaldehyde in Las Vegas, NV. Results indicated that MSAT concentrations often did not exhibit trends typical of other primary emitted pollutants in this study. Instead, other mobile sources beyond the highway of interest contributed to the measured values, including a major arterial road, a large commercial airport, and a nearby parking lot. The data were compared with relevant census-tract NATA estimates, with estimated ambient 1,3-butadiene concentrations similar to the measured values. Measured benzene values were much lower relative to the NATA total ambient benzene concentrations. Measured acrolein values were much higher relative to the NATA total acrolein concentrations. Measured acetaldehyde and formaldehyde values were also higher relative to the NATA total acetaldehyde and formaldehyde concentrations for all wind conditions and downwind conditions. Some possible explanations for these differences include nearby sources influencing the measured values; meteorological influences that may not be well captured by the NATA modeling regime; chemical reactivity of measured compounds; and additional explanatory variables may be needed for certain urban areas in order to accurately disaggregate anthropogenic air toxics emissions.

Implications: Comparison of air toxics concentrations measured at four long-term near-road sites in Las Vegas, NV, show generally good agreement with the EPA 2005 U.S. Environmental Protection Agency. 2005. National Air Toxics Assessments (NATA)(accessed December 7, 2012) http://www.epa.gov/ttn/atw/natamain/index.html (http://www.epa.gov/ttn/atw/natamain/index.html)  [Google Scholar] NATA total ambient concentrations. Measured concentrations did not compare as well with EPA 2005 U.S. Environmental Protection Agency. 2005. National Air Toxics Assessments (NATA)(accessed December 7, 2012) http://www.epa.gov/ttn/atw/natamain/index.html (http://www.epa.gov/ttn/atw/natamain/index.html)  [Google Scholar] NATA for the on-road mobile portion of the ambient concentrations. This highlights the complexity of air toxic emission sources and impacts in urban areas, especially around large highway facilities; NATA's inability to capture local-scale meteorology and fine-scale ambient gradients; and that additional explanatory variables may be needed for certain urban areas in order to accurately disaggregate anthropogenic air toxics emissions.     

Eutrophication of Lake Tasaul, Romania—proposals for rehabilitation

Lake Tasaul on the Black Sea coast is highly eutrophic, but not strongly contaminated (heavy metals, PAHs, and organochlorine pesticides). Cyanophytes dominate phytoplankton by 67–94% and form frequent algal blooms. High primary production (up to 270 mg C_ass/m².h) and algal biomass (maximum chlorophyll a concentration 417 μg/l) may be controlled by light, as Secchi depth is often below 1 m. The main tributary, Casimcea River, provides high quantities of suspended matter and about 3 tons TP/year and 660 tons TN/year. Based on chemical and biological analysis as well as fishery investigations, we provide recommendations for Lake Tasaul rehabilitation.     

Magnetic nanocomposites for sustainable water purification—a comprehensive review

Numerous contaminants in huge amounts are discharged to the environment from various anthropogenic activities. Waterbodies are one of the major receivers of these contaminants. The contaminated water can pose serious threats to humans and animals, by distrubing the ecosystem. In treating the contaminated water, adsorption processes have attained significant maturity due to lower cost, easy operation and environmental friendliness. The adsorption process uses various adsorbent materials and some of emerging adsorbent materials include carbon- and polymer-based magnetic nanocomposites. These hybrid magnetic nanocomposites have attained extensive applications in water treatment technologies due to their magnetic properties as well as combination of unique characteristics of organic and inorganic elements. Carbon- and polymer-related magnetic nanocomposites are more adapted materials for the removal of various kinds of contaminants from waterbodies. These nanocomposites can be produced via different approaches such as filling, pulse-laser irradiation, ball milling, and electro-spinning. This comprehensive review is compiled by reviewing published work of last the latest recent 3 years. The review article extensively focuses on different approaches for producing various carbon- and polymer-based magnetic nanocomposites, their merits and demerits and applications for sustainable water purification. More specifically, use of carbon- and polymer-based magnetic nanocomposites for removal of heavy metal ions and dyes is discussed in detail, critically analyzed and compared with other technologies. In addition, commercial viability in terms of regeneration of adsorbents is also reviewed. Furthermore, the future challenges and prospects in employing magnetic nanocomposites for contaminant removal from various water sources are presented.

     

Eutrophication of Lake Tasaul,Romania—proposals for rehabilitation

Background, aim, and scope  The reclamation of nonferrous metal-polluted soil by phytoremediation requires an overall and permanent plant cover. To select the most suitable plant species, it is necessary to study metal effects on plants over the time, thereby checking that metals remain stored in root systems and not transferred to aerial parts. In this purpose, the seasonal and annual variations of metal bioaccumulation, transfer, and phytotoxicity in Trifolium repens and Lolium perenne grown in a Cd-, Pb-, and Zn-contaminated soil were also studied. Materials and methods  The experimental site was located near a closed smelter. In spring 2004, two areas were sown with T. repens and L. perenne, respectively. Thereafter, the samplings of plant roots and shoots and surrounding soils were realized in autumn 2004 and spring and autumn 2005. The soil agronomic characteristics, the Cd, Pb, and Zn concentrations in the surrounded soils and plant organs, as well as the oxidative alterations (superoxide dismutase [SOD], malondialdehyde [MDA], and 8-hydroxy-2′-deoxyguanosine [8-OHdG]) in plant organs were carried out. Results  Whatever the sampling period, metal concentrations in soils and plants were higher than background values. Contrary to the soils, the fluctuations of metal concentrations were observed in plant organs over the time. Bioaccumulation and transfer factors confirmed that metals were preferentially accumulated in the roots as follows: Cd>Zn>Pb, and their transfer to shoots was limited. Foliar metal deposition was also observed. The results showed that there were seasonal and annual variations of metal accumulation in the two studied plant species. These variations differed according to the organs and followed nearly the same pattern for the two species. Oxidative alterations were observed in plant organs with regard to SOD antioxidant activities, MDA, and 8-OHdG concentrations. These alterations vary according to the temporal variations of metal concentrations. Discussion  Metal concentrations in surrounded soils and plant organs showed the effective contamination by industrial dust emissions. Metals absorbed by plants were mainly stored in the roots. With regard to this storage, the plants seemed to limit the metal transfer to their aerial parts over the time, thereby indicating their availability for metal phytostabilization. Aerial deposition was another source of plant exposure to nonferrous metals. Despite the occurrence of metal-induced oxidative alterations in plant organs, both plant species seemed to tolerate a high metal concentration in soils. Conclusions  Taken together, these results indicated that T. repens and L. perenne were able to form a plant cover on highly Cd-, Pb-, and Zn-polluted soils, to limit the metal transfer to their aerial parts and were relatively metal-tolerant. All these characteristics made them suitable for phytostabilization on metal-contaminated soils. These findings also highlighted the necessity to take into account seasonal and annual variations for a future phytomanagement. Recommendations and perspectives  In this work, the behavior of plant species grown in metal-polluted soil has been studied during 2 years. Obviously, this time is too short to ensure that metals remain accumulated in the root system and few are transferred in aerial parts over the time. It is why regular monitoring should be achieved during more than a decade after the settlement of the plant cover. This work will be completed by the study of the T. repens and L. perenne effects on mobility of metals in order to evaluate the quantities of pollutants which could be absorbed by the biota and transferred to groundwater. Bioaccessibility tests could be also realized on polluted soils in order to evaluate the phytostabilization impacts on the exposition risks for humans.     

Soiling Potential—A New Method for Measuring Smoke Emission

There is a growing interest in effects of sub-micron, nonsettling particles in the atmosphere among air pollution control agencies throughout the country. This type of pollution, generally referred to as the “soiling index” of the atmosphere, is produced primarily by the incomplete combustion of fuels. The measurement procedure has been fairly well standardized, the values being reported as Cohs or Ruds per 1000 linear feet of air. Using a similar technique, a method of quantitating smoke emission in objective terms first demonstrated by W. C. L. Hemeon in 1953, has been applied to source testing at several operating plants by the Cincinnati Division of Air Pollution Control. The source strength will be called “soiling potential” while the effect in the general atmosphere is termed “soiling index.” The soiling potential unit is Rud-ft² per cubic foot exhaust gases or Rud-ft² per unit of fuel input. The “Soiling Potential” sampler is described and results of tests are given. Included is the use of soiling potential in quantitating smoke emission from single sources and for constructing area wide inventory of smoke emission. The use of an area wide smoke emission inventory in Rudft2 in a simple diffusion model for calculating the soiling index (Rud-ft²/1000 cu ft) in the general atmosphere at a given point is explored.     

An Air Quality Data Analysis System for Interrelating Effects,Standards, and Needed Source Reductions: Part 13— Applying the EPA Proposed Guidelines for Carcinogen Risk Assessment to a Set of Asbestos Lung Cancer Mortality Data

Abstract

The Clean Air Act Amendments of 1990 (CAAA-90) list 189 hazardous air pollutants (HAPs) for which “safe” ambient concentrations are to be determined. The primary purpose of this paper is to develop two mathematical models, lognormal and logarithmic, that effectively express excess lung cancer mortality as a function of asbestos concentration for an example set of data and also to suggest using these two models for additional HAPs. The secondary purpose of this paper is to calculate a “safe” asbestos concentration by first assuming a default linear extrapolation (to one excess death per million people, as specified for carcinogenic HAPs). The resulting “safe” concentration is an impossible-to-achieve 1/1000 of present background asbestos concentrations. A letter to the editor and a response in this Journal issue use additional asbestos data that suggest that the “safe” concentration should be about 730 times higher than first calculated here and that a default nonlinear extrapolation should be used instead, with the “safe” concentration proportional to the desired mortality level raised to the 0.39 power. These results suggest that the most important problem in setting a “safe” concentration for each carcinogenic HAP is to determine the correct nonlinear extrapolation to use for each HAP.