Automotive sources

Reactions involving the catalytic reduction of nitrogen oxides are of major environmental importance for the removal of toxic emissions from both stationary and automotive sources. As shown in this section electrochemical promotion can affect dramatically the performance of Rh, Pd and Pt catalysts (commonly used as exhaust catalysts) interfaced with YSZ, an O2 ion conductor. The main feature is strong electrophilic behaviour, i.e. enhanced rate and N2 selectivity behaviour with decreasing Uwr and , due to enhanced NO dissociation. 

Operando studies for NO removal from automotive sources... 

In developing a multiple regression model for apportioning sources of TSP in New York City, Kleinman, et al.(2) selected Pb, Mn, Cu, V and SO, as tracers for automotive sources, soil-related sources, incineration, oil-burning and secondary particulate matter, respectively. These were chosen on the basis of the results of factor analysis and a qualitative knowledge of the principal types of sources in New York City and the trace metals present in emissions from these types of sources. Secondary TSP, automotive sources and soil resuspension were found to be the principal sources of TSP in 1974 and 1975 ( ). 

As lead in automotive emissions has been found largely in the fine particle fraction (22, 23), it is reasonable to expect a similar size distribution pattern for manganese from automotive sources. This would explain the strong association between MN and PB in the factor analyses reported here. This probably also explains the association of MN (TSP samples) with several factors at low loadings, rather than with a single factor as the TSP samples would include the mass of respirable as well as coarse manganese. When the concentration of the tracers in coarse particles (calculated as the differences in concentration between the TSP and RSP samples) were included with the RSP data for factor analysis, a factor on which 20% of the total variance (No. 5, Table I) was loaded was obtained. 

Based on these results and considerations, it was concluded that Pb, V, Cu and SO. could be used as source tracers for automotive sources, oil-burning, incineration and secondary (or sulfate-associated) sources, respectively. Mn, however, should probably be considered as a composite tracer of automotive emissions and soil-related sources (resuspension of dust). 

The most appropriate models for CYC is probably equation (14) as this is the simplest and is most closely related to the results of the factor analysis which indicated that the variances in CYC were most closely related to those in V and PB. The inclusion of coarse particle manganese as a soil tracer diminished the significance of the coefficient of PB and the contribution of automotive sources. Ideally, MN would be used as a tracer for resuspended soil but Interferences from the use of MMT as a fuel additive during part of the period in which this data were collected make this a mixed source tracer for the contributions of automobiles and soil resuspension. 

Using equation (20), with MN used as a mixed tracer to calculate source contributions, 2.64 yg/m" (53%) of ACE was estimated to originate from automotive sources plus soil resuspension, in good agreement with the calculations based on equation (18). 

Dickhut, R.M., Canuel, E.A., Gustafson, K.E., Liu, K., Arzayus, K.M., Walker, S.E., Edgecombe, G., Gaylor, M.O., and Macdonald, E.H. (2000) Automotive sources of carcinogenic polycyclic aromatic hydrocarbons associated with particulate matter in the Chesapeake bay region. Environ. Sci. Technol. 34, 4635-4640. 

Na on a mass basis), h from pH, total As (sum of soluble and insoluble)f and soluble Pb over the network for a storm sampled on February 14-15, 1985. For this stormf the insoluble fraction of As was 20 percent of the concentrations in the soluble phase and was very similiar to soluble As in geographical distribution. Except for Pb, the plotted concentrations are highest just to the northeast of the smelter. Pb and NO are generally highest in the Seattle area and further northeast although Pb was also elevated near the copper smelter for other storms collected by our network. This is consistent with a possible automotive source of Pb and NCK in the Seattle area. 

Examples of models applicable to emissions from automotive sources, aircraft, and power plants are presented below. Distributed sources may... 

The emission of NOx from both stationaiy and automotive sources has serious environmental implications. Ammonia can be used to reduce NO from stationaiy sources, but such an approach caimot easily be implemented on motor vehicles. The diree-way automotive catalyst has been liighly successful in controlling exliaust emissions from conventional petrol engines which operate under closed-loop... 

For these days and many others not shown, the results are suflBciently similar in character to those from Livermore that one can conclude that an automotive source alone would be suflBcient to explain the Pb concentrations. 

To substantiate the above conclusion, samples from a number of suspected predominately automotive source days were multi-element... 

The x-ray fluorescence analysis thus selected these three days as candidates for days on which a major component of the Pb aerosol was from a non-automotive source. To establish that this was the case and actually to determine the nature of the non-automotive source, a multi-... 

The main catalyst site poison for many years was tetraethyllead [78-00-2]y C H ven after use of unleaded gasoline. Not only is lead a catalyst poison, but automotive source lead is also a health hazard (66). The source of this lead came from manufacture and distribution of leaded and unleaded gasoline in common transport equipment and storage facilities (67). In the eady 1990s, so Htde leaded gasoline was being distributed that Pb contamination was approaching zero (<0.26 ppm/L). 

At least ten times more carbon monoxide enters the atmosphere from natural sources than from all industrial and automotive sources combined. Of the 3.8 billion tons of carbon monoxide emitted every year, about 3 billion tons are emitted by the oxidation of decaying organic matter in the topsoil. In spite of this fact, carbon monoxide is considered an air pollutant, primarily because so much of it is produced by human activities in the urban environment. 

It has been indicated in earlier chapters that industrial emissions of lead contribute little on a nationwide basis to lead in the air, in comparison with automotive sources. This is largely a result of the very tight control exercised over industrial sources of lead, using techniques which will be described in this chapter. Nevertheless, as shown in Chapter 2, industrially emitted lead may have a considerable local effect upon air quahty, and if ambient air quality standards such as that in the USA (1.5 jUg mT ) are to be met, then considerable improvements in emission control installations will be required. 

Olson, K.W., Skogerboe, R.K., 1975. Identification of soil lead compounds from automotive sources. Environ. Sci. Technol. 9, 227—230. 

Figure 1.3 Nonwovens versus competing materials in automotive. Source Data Kellie Solutions Ltd.

The three types of emissions from automotive sources that are of primary concern are unburned hydrocarbons (from either evaporation or the tailpipe), carbon monoxide (CO) and nitrogen oxides (NOx). The latter two are tailpipe emissions only. Most hydrocarbons and NOx are not of concern directly, but they do react with oxygen in the atmosphere under intense sunlight to form ozone, the basic ingredient of urban smog. CO is, of course, directly harmful to human health and is of direct concern. 

X-ray diffraction is a qualitative and quantitative method for the analysis of minerals [43]. In this method, the repeating interplanar spacings in a crystal are measured by determining the angles of X-rays reflected from the crystal planes. Olson and Skogerboe [51] have used X-ray diffraction in the identification of soil lead compounds from automotive sources. 

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