A quantitative approach to the traffic air quality problem: the Traffic Air Quality index

The Traffic Air Quality (TAQ) model is a simple tool to estimate traffic fine particulate emissions on roadways (g/km) and can be used for both real-time analysis and for localized conformity analysis ("hot-spot" analysis for nonattainment areas) as defined by 40 CFR 93.123. This paper is a follow-up to a study published earlier regarding the development of the TAQ model. This paper shows how local air quality levels can be a factor in traffic management in nonattainment areas. Similar to the industrial source quotas measured in tons per year, it is proposed that road segments are to be assigned emission quotas (or TAQ indices) measured in pollutant mass emitted per road length (g/km) above which traffic-measures have to be taken to reduce the fine-particulates emissions on such road links. The TAQ model as well as traffic-rerouting measures along with the Intelligent Transportation System (ITS) protocols can be used to have a real-time control of the traffic conditions along expressways to maintain the fine-particulates emissions below the quota assigned per road link and consequently improving the over all local air quality in nonattainment areas.     

Development of an empirical model to estimate real-world fine particulate matter emission factors: the traffic air quality model

The purpose of the study was to quantify the impact of traffic conditions, such as free flow and congestion, on local air quality. The Borman Expressway (I-80/94) in Northwest Indiana is considered a test bed for this research because of the high volume of class 9 truck traffic traveling on it, as well as the existing and continuing installation of the Intelligent Transportation System (ITS) to improve traffic management along the highway stretch. An empirical traffic air quality (TAQ) model was developed to estimate the fine particulate matter (PM2.5) emission factors (grams per kilometer) based solely on the measured traffic parameters, namely, average speed, average acceleration, and class 9 truck density. The TAQ model has shown better predictions that matched the measured emission factor values more than the U.S. Environmental Protection Agency (EPA)-PART5 model. During congestion (defined as flow-speeds < 50 km/hr [30 mi/hr]), the TAQ model, on average, overpredicted the measured values only by a factor of 1.2, in comparison to a fourfold underprediction using the EPA-PART5 model. On the other hand, during free flow (defined as flow-speeds > 80 km/hr [50 mi/hr]), the TAQ model was conservative in that it overpredicted the measured values by 1.5-fold.     

APCA Financial Statements for 1975-1976

Abstract

A wind tunnel study was completed to determine the effects the presence of a parapet and raised intake configurations have on the dilution of a pollutant between a rooftop stack and building intake. This study was the first to address the effects of building parapets and varying intake configurations. A study of this kind is desirable because it is common practice for architects to attempt to hide stacks with the use of a parapet in order to make industrial buildings more aesthetically pleasing. This is done with no thought to the effect it may have on the intended function of the stacks, which is dispersing gases away from the building to avoid contamination of ventilation air.

Three parapet configurations (no parapet and two different parapet heights) and two intake configurations (flush and raised) were investigated. The relative effects of the parapets and the raised intake configurations were also compared and contrasted for five stack heights, two stack locations, and four intake locations.

The parapets were found to produce a cavity zone that extends above the building's roof by as much as two times the physical height of the parapet; increasing stack height had little effect on dispersion until the stack extended beyond this cavity region. The independent use of the parapets and raised intake configuration decreased the number of dilutions occurring between stack and intake when compared to the no parapet and flush intake configurations in all cases. Also substantiated in this study is the widely accepted view that the effect of the parapet addition is to decrease the effective stack height by the parapet height itself.

The results of this investigation were then compared to existing wind tunnel-derived empirical models. The models tested were not able to predict the effects of varying stack height and of varying the relative distance between stack and intake on the dilution of a pollutant between stack and intake under the tested configurations.     

Model for forecasting expressway fine particulate matter and carbon monoxide concentration: application of regression and neural network models

The Borman Expressway is a heavily traveled 16-mi segment of the Interstate 80/94 freeway through Northwestern Indiana. The Lake and Porter counties through which this expressway passes are designated as particulate matter < 2.5 microm (PM2.5) and ozone 8-hr standard nonattainment areas. The Purdue University air quality group has been collecting PM2.5, carbon monoxide (CO), wind speed, wind direction, pressure, and temperature data since September 1999. In this work, regression and neural network models were developed for forecasting hourly PM2.5 and CO concentrations. Time series of PM2.5 and CO concentrations, traffic data, and meteorological parameters were used for developing the neural network and regression models. The models were compared using a number of statistical quality indicators. Both models had reasonable accuracy in predicting hourly PM2.5 concentration with coefficient of determination -0.80, root mean square error (RMSE) <4 microg/m3, and index of agreement (IA) > 0.90. For CO prediction, both models showed moderate forecasting performance with a coefficient of determination -0.55, RMSE < 0.50 ppm, and IA -0.85. These models are computationally less cumbersome and require less number of predictors as compared with the deterministic models. The availability of real time PM2.5 and CO forecasts will help highway managers to identify air pollution episodic events beforehand and to determine mitigation strategies.     

Reduction of Open Hearth Furnace Particulate Emissions via a Parametric Study

A linear relationship has been found between oxygen usage and particulate mass emission rate for a basic open hearth furnace. Particulate emissions were found to pass through a minimum at 50% hot metal addition to the furnace which also corresponded to minimum oxygen consumption. Number 2 dealer scrap and hot metal addition were found to have a secondary effect on the particulate emissions. Variation of number 2 dealer scrap from 0 to 15% of the charge and hot metal from 10 to 70% resulted in a maximum 44% increase in particulate emissions. Aerodynamic particle size distributions for all heats and within heats were relatively invariant with an average mass median diameter of 1.4µ     

中国煤中氟的含量及其分布

在全国主要产煤的26个省、市和自治区根据各煤田的地质储量、成煤时期和煤变质程度,兼顾各矿区的煤炭产量,采集305个煤样,用高温热水解-离子选择性电极法测定了全部样品的氟含量.煤中的氟主要以无机形态赋存,氟含量和变质程度之间没有必然的联系.成煤时代等单一因素对氟含量的影响可能为其它各种因素的综合作用所掩盖,对此有必要进行更深入、具体的研究研究了各省、市和自治区的煤氟含量的分布,有必要重新审视、甄别燃煤型氟中毒区氟的来源.全国煤的氟含量服从对数正态分布,90%的样品含氟范围为47～347mg/kg,宜用几何平均值136mg/kg作为全国平均煤氟含量.与世界煤相比,中国煤氟含量并无异常.     

Trace Metal Samples Collected in the Front and Back Halves of the E.P.A. Stack Sampling Train

A Purdue University industrial source sampling team has been involved since 1972 with a number of industrial and municipal collaborators, in order to characterize the flow of trace metals into the atmosphere. The plants involved in this cooperative research effort include the East Chicago municipal incinerator, rated at 450 ton/day of residential and commercial solid waste; a multiple furnace open hearth shop at a Northwest Indiana steel mill producing approximately 8 million ton/yr of steel; a coker arid sinter plant serving a 100,000 ton/yr vertical retort zinc production facility; and the Purdue University coal fired power plant equipped with 250,000 lb/hr steam boilers. At each of these facilities a number of stack samples have been obtained using the standard E.P.A. train. Analysis of the probe, filter, and impinger catch showed that in each case the front half of the E.P.A. Method 5¹ sampling train was highly efficient for collection of trace metal particulate.