Penetration of Evaporative Emissions into a Home from an M85-Fueled Vehicle Parked in an Attached Garage

ABSTRACT

The use of both oxygenated fuels in carbon monoxide (CO) nonattainment areas and reformulated gasoline in ozone nonattainment areas has been mandated by the 1990 Clean Air Act Amendments. Methanol has been proposed as an alternative fuel for CO nonattainment areas. Its use will potentially increase indoor methanol inhalation exposure resulting from the evaporation of metha-nol vapor from methanol-fueled vehicles parked in residential garages. Indoor air concentrations of metha-nol, benzene, and toluene were measured in a residential home with an attached garage. The effects of vehicle emission control devices (charcoal canister hose connection); home heating, ventilation, and air conditioning (HVAC) fans; ambient air, garage, and fuel tank temperatures; and wind speed were examined.

The disconnection of the charcoal canister hose, which simulates a spent evaporative emission control device, resulted in elevated benzene, toluene, and metha-nol concentrations in the garage and attached home. Higher fuel tank temperatures resulted in higher benzene and toluene concentrations in the garage, but not methanol. The concentrations for all compounds in the garage and concentrations of benzene and toluene in the adjacent room were lower when the HVAC fan was on than when it was off, while the concentrations of all three compounds in the rest of the house were higher, although these differences were not statistically significant. Thus, the portion of the population that parks cars in garages attached to homes will experience increased methanol exposures if methanol is used as an automotive fuel.     

Characteristics of Road Dust from Different Sampling Sites in Northern Taiwan

Abstract

Road dust contributes a large percentage of the atmosphere’s suspended particles in Taiwan. Three road dust samples were collected from downtown, electrical park, and freeway tunnel areas. A mechanical sieve separated the road dust in the initial stage. Particles >100 μm were 75%, 70%, and 60% (wt/wt), respectively, of the samples. Those particles <37 μm were resuspended in another mixing chamber and then collected by a Moudi particle sampler. The largest mass fraction of resuspended road dust was in the range of 1–10 μm. Ultrafine particles (<1 μm) composed 33.7, 17, and 7.4% of the particle samples (downtown, electrical park, and freeway tunnel, respectively). The road dust compositions were analyzed by inductively coupled plasma (ICP)-atomic emissions spectroscopy and ICP-mass spectrometry. The highest concentration fraction contained more aluminum (Al), iron (Fe), calcium (Ca), and potassium than other elements in the road dust particle samples. Additionally, the sulfur (S) content in the road dust from the electrical park and freeway tunnel areas was 2.1 and 3.4 times the downtown area sample, respectively. The sulfur originated from the vehicle and boiler oil combustion and industrial manufacturing processes. Furthermore, zinc (Zn) concentration in the tunnel dust was 2.6 times that of the downtown and electrical park samples, which can be attributed to vehicle tire wear and tear. Resuspended road dusts (<10 μm) from the downtown and freeway tunnel areas were principally 2.5–10 μm Al, barium (Ba), Ca, copper (Cu), Fe, magnesium (Mg), sodium (Na), antimony (Sb), and Zn, whereas arsenic (As), chromium (Cr), and nickel (Ni) were predominant in the ultrafine particle samples (<1 μm). Al, Ba, and Ca are the typical soil elements in coarse particles; and As, and Cr and Ni are the typical fingerprint of oil combustion and vehicle engine abrasion in ultrafine particles. There was a special characteristic of resuspension road dust at electrical park, that is, many elements, including As, Ba, Ca, cadmium, Cr, Cu, Fe, manganese (Mn), Ni, lead (Pb), S, vanadium (V), and Zn, were major in ultrafine particles. These elements should be attributed to the special manufacturing processes of electric products.     

The association between maternal nonylphenol exposure and parity on neonatal birth weight: A cohort study in Taiwan

Background

The aim of this study was to explore the association between NP exposure and parity and their effect on neonatal birth weight.

Methods

A cohort of pregnant women was established in a medical center in North Taiwan. Urinary NP concentration was determined by high-performance liquid chromatography coupled with fluorescent detection and adjusted using creatinine. A multivariable regression model was fit to determine the association between the maternal NP level in each trimester and neonatal birth weight. The odds ratios (ORs) of infant birth weight below the 10th, 25th, and 50th percentiles, comparing pregnant women with the different NP exposure levels, was estimated using a logistic regression.

Results

Of the 162 pregnant women in the study, 99 were multiparas and 63 were primiparas. After adjusting for other covariates, the NP level in the second trimester had a significant association with birth weight in the primiparas (β = −182.49 g, p value = 0.02). The OR of low infant birth weight, comparing pregnant women with different NP levels, was increased by decreasing the cutoff percentile for birth weight (OR = 1.18 for the 50th percentile, 2.12 for the 25th percentile, and 7.81 for the 10th percentile). The odds of primiparas with high NP level having a low neonatal birth weight increased to 3.87, 11.77, and 9.40 for the three different percentiles (p value < 0.05).

Conclusion

Maternal NP exposure level is associated with an increased risk of low neonatal weight. Primiparas are especially at risk, and the second trimester of pregnancy may be the critical stage of exposure.     

Fate of anilide and aniline herbicides in plant-materials-amended soils

The fate of herbicides trifluralin, pendimethalin, alachlor and metolachlor in paddy field soils amended with plant materials was investigated. The plant materials were purple sesbania, vegetable soybean and rice straw. The investigation was performed at two temperatures (25 and 40°C) and two soil water moistures (60 and 90% water-holding capacity). The results showed linear and Freudlich equations described the adsorption of amide compound to soil. Adsorption coefficient (K _d ) fit to linear equation were in general greater in plant material-amended soils than in non-amended soil, especially in soil amending with rice straw. Increasing temperature and soil water moisture content shortened the half-lives of compounds in various treated soils. The movement of compounds in the soil columns showed the maximum distribution of aniline type compound, trifluralin and pendimethalin, appeared at the upper top of 0 to 5 and 0 to 10 cm of soil column, respectively, and of anilide type, alachlor and metolachlor, were distributed at 0 to 25 cm of the soil column. The mobility of chemicals in the different treated soils was simulated by the behavior assessment model (BAM). There was no significant difference among different plant material incubated soils on dissipation and mobility of compounds in soils.     

Environmental design implementation in Taiwan's industries

This study investigated Taiwan's industries to identify the characteristics of companies most advanced in environmental design. Thirty design principles in five categories were used to define advanced environmental design. The five categories are: use of raw materials, use of energy, design for recyclability, product life cycle assessment, and packaging optimization. We found that of the 30 design principles only eight were applied consistently by Taiwanese manufacturers. Most effort was given to the “use of energy” category. The most advanced environmental design was found at large companies—those with over 2000 employees, 3 billion in capital, and/or 3 billion in annual sales.     

A fuzzy risk assessment approach for occupational hazards in the construction industry

The techniques in the construction industry have been improved due to the rapid development of science and technology. However, the constructional hazards are not decreased as expected. To reduce or prevent occupational hazards in the construction industry, a fuzzy risk assessment method was proposed to provide a prevention and improvement technique against occupational hazards. This method used two-stage quality function deployment (QFD) tables to represent the relationships among construction items, hazard types and hazard causes. A fuzzy analytic network process (ANP) method was developed to identify important hazard types and hazard causes. Failure modes and effect analysis (FMEA) was performed to assess the risk value of hazard causes based on the fuzzy inference approach. The proposed method was applied to a telecom engineering company in southern Taiwan. The performance evaluation result indicated that this method can provide satisfactory risk assessment values of hazard causes and relevant improvement strategies.     

Relationship between air pollution and daily mortality in a subtropical city: Taipei, Taiwan

Air pollution has been associated with daily mortality in numerous studies over the past decade. However most of these studies were conducted in the United States and Europe with relatively few done in Asia. In the current study, the association between ambient air pollution and daily mortality in Taipei, Taiwan's largest city which has a subtropical climate was undertaken, for the period 1994-1998 using a case-crossover analysis. This design is an alternative to Poisson time series regression for studying the short-term adverse health effects of air pollution. The air pollutants examined included particulate matter (PM(10)), sulfur dioxide (SO(2)), ozone (O(3)), nitrogen dioxide (NO(2)), and carbon monoxide (CO). The largest observed effect, which was without statistical significance, was seen for NO(2) and CO levels on deaths due to respiratory diseases (ORs=1.013 and 1.014, respectively). The well established link between air pollution levels and daily mortality may not be as strong in cities in subtropical areas, although other factors such as differences in pollutant mix or the underlying health of the population may explain the lack of a strong association in this study. Further studies of this type in cities with varying climates and cultures are needed.     

Simultaneous sampling of gas- and aerosol-phase TDI with a triple filter system

A new triple filter system sampler/model is proposed for the precise and accurate simultaneous sampling and determination of gas- and aerosol-phase 2,4-toluene diisocyanate (TDI). The system consists of two front Teflon filters for sampling aerosol-phase TDI and a final coated glass fiber filter to collect gas-phase TDI. The aerosol-phase TDI is collected on the first Teflon filter, while the second Teflon filter is used to estimate gaseous TDI adsorbed by the first. According to the gas adsorption test of two Teflon filters in series, the TDI gas adsorption fraction of the two filters is almost the same. Results of the evaporation test using pure TDI aerosols collected on the Teflon filter show that significant evaporation of the compound does not occur during sampling. These two findings allow the use of a model to estimate accurate gas- and aerosol-phase TDI concentrations. The comparison test with an annular denuder shows that the triple filter system can minimize the TDI sampling bias between the dual filter and the annular denuder systems.     

Dynamical coupling of PBPK/PD and AUC-based toxicity models for arsenic in tilapia Oreochromis mossambicus from blackfoot disease area in Taiwan

A physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) models were developed for arsenic (As) in tilapia Oreochromis mossambicus from blackfoot disease area in Taiwan. The PBPK/PD model structure consisted of muscle, gill, gut wall, alimentary canal, and liver, which were interconnected by blood circulation. We integrate the target organ concentrations and dynamic response describing uptake, metabolism, and disposition of As and the associated area-under-curve (AUC)-based toxicological dynamics following an acute exposure. The model validations were compared against the field observations from real tilapia farms and previously published uptake/depuration experimental data, indicating that predicted and measured As concentrations in major organs of tilapia were in good agreement. The model was utilized to reasonably simulate and construct a dose-dependent dynamic response between mortality effect and equilibrium target organ concentrations. Model simulations suggest that tilapia gills may serve as a surrogate sensitive biomarker of short-term exposure to As. This integrated As PBPK/PD/AUC model quantitatively estimates target organ concentration and dynamic response in tilapia and is a strong framework for future waterborne metal model development and for refining a biologically-based risk assessment for exposure of aquatic species to waterborne metals under a variety of scenarios.     

Diffusion of hydrogen sulfide and methyl mercaptan onto microporous alkaline activated carbon

Activated carbon kinetic studies show that both H2S and CH3SH yielded pore diffusion coefficients from 10(-6) to 10(-8) cm2/s. Results indicated that pore structures could influence effective diffusivity. Under the same adsorbate concentration, CH3SH exhibited a greater effective pore diffusion coefficient than H2S. This may be attributed to the fact that CH3SH has both polar (-SH) and non-polar (-CH3) functional groups and dissolves into water easier, thus providing more attraction for the activated carbon surface. In addition, the saturation vapor pressure of CH3SH is lower than that of H2S. Therefore, CH3SH is easier to adsorb onto activated carbon than H2S.