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.     

A Simplified Method for Characterizing a Motor Vehicle’s Exhaust Emissions

The purpose of this study was to gather air quality data for four pollutants inside and outside of three pairs of structures for different seasons of the year. This paper presents results obtained during the summer, fall, and winter seasons of 1969–70. Suspended particulate, soiling particulate, carbon monoxide, and sulfur dioxide were measured at pairs of public buildings, office buildings, and private homes. A brief preliminary program was conducted during the winter of 1969 to verify our procedures and equipment and to assess the effects of heating and cooking systems in private homes on indoor levels of air pollutants. Two self-contained and portable instrument packages were constructed for the measurement program. The major components of each trailer package were a central vacuum pump for drawing air samples through particulate collection niters, four paper-tape soiling samplers, a conductimetric analyzer for sulfur dioxide, an infrared analyzer for carbon monoxide, a master control unit, and supporting apparatus to make the trailer self-contained. Each pair of buildings was sampled simultaneously for a two-week period. Four sampling points were selected at each structure, two outside and two inside. Suspended particulate samples were collected for 12-hr day and night periods, soiling particulate samples for 2-hr periods, and gaseous samples for 5-min periods. The results show the ease of penetration of particulate into private homes and the removal ability of air conditioning systems. Outdoor daily activity greatly influences particulate levels and urban carbon monoxide levels. Internal generation of pollutants was a significant factor in measured interior concentrations in some of the structures sampled.     

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.     

A Comparative Assessment of Flue Gas Treatment Processes Part I—Status and Design Basis

The developmental status, projected costs, and environmental effects of 14 flue gas treatment processes are compared on a common basis in two consecutive issues of JAPCA. Part I summarizes the background and study basis and Part II compares environmental impact and relative costs. Each process is assumed to be associated with a grass roots installation that includes a modern 800 MW power plant burning Illinois No. 6 coal. Also considered is the effectiveness of these processes to control particulate matter, NO _x , trace inorganics, and polyorganic matter.

The processes are divided into those operating once-through (Limestone, Lime, Limestone and Lime, Dual-Alkali), and with regeneration (Magnesia, Wellman-Lord, Citrate, Aqueous Carbonate, IFP-Catalytic Inc., Copper-Dry Bed, and Carbon-Dry Bed). Also analyzed are NO _x control processes that are compatible with scrubbers or dry processes, and include the Exxon Thermal DeNO _x , Ozone NO Oxidation, and Copper and Carbon-Dry Bed.     

A Comparative Assessment of Flue Gas Treatment Processes Part II—Environmental and Cost Comparison

The developmental status, projected costs, and environmental effects of 14 flue gas treatment processes are compared on a common basis in two consecutive issues of JAPCA. Part I summarized the background and study basis and Part II compares environmental impact and relative costs. Each process is assumed to be associated with a grass roots installation that includes a modern 800 MW power plant burning Illinois No. 6 coal. Also considered is the effectiveness of these processes to control particulate matter, NO_x, trace inorganics, and polyorganic matter.

The processes are divided into those operating once-through (Limestone, Lime, Limestone and Lime, Dual-Alkali), and with regeneration (Magnesia, Wellman-Lord, Citrate, Aqueous Carbonate, IFP-Catalytic Inc., Copper-Dry Bed, and Carbon-Dry Bed). Also analyzed are NO_x control processes that are compatible with scrubbers or dry processes, and include the Exxon Thermal DeNO_x, Ozone NO Oxidation, and Copper and Carbon-Dry Bed.     

Development of an In-Line System for the Analysis of 4,4′-DDT in Water

An in-line system for trace persistent organic pollutants (POPs) in water was developed by using a laboratory-made hollow fiber membrane (HFM) unit connected with a high-resolution gas chromatograph-mass spectrometer (HRGC-MS). The semivolatile organic compound, 4,4′-Dichlorodiphenyl trichloroethane (4,4′-DDT), was chosen as a representative of a persistent organic compound. The synthetic water contaminated with 4,4′-DDT was passed through the HFM unit, the extraction occurred by the analyte pervaporated and permeated, then stripped into HRGC-MS. Several factors were investigated for the high extraction efficiency. The best performance was obtained at sample and stripping gas flow rates of 6 and 9 mLmin^?1, respectively, and desorption temperature of 60°C. At this temperature, the diffusion rate was enhanced by 15 times over 25°C. A wide linear dynamic range was obtained, i.e., 0.10–1.0 mgL^?1, with a limit of detection (LOD) of 90 μgL^?1. The extraction efficiency of 4,4′-DDT in real water samples was in the range of 83–94%. Real water samples were analyzed and 0.6 μgL^?1 of 4,4′-DDT was found in unregistered bottled water and 7.0 μgL^?1 in tap water.     

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—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.     

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.     

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.