Traffic emission and its impact on air quality in Guangzhou area

A comprehensive field measurement was set up in Guangzhou City of China and the key was placed on NO\-x and O\-3 pollution. The results indicated that the average driving speed of vehicle was only 14 km/h in downtown with high frequency of idle and acceleration. Upward fluxes of CO and NO were observed in Dongfeng Street. NO\-x annual mean concentration in urban area increased year by year, and NO\-x was identified as the most important pollutant since 1995. Photochemical smog pollution was serious in general, spatial and seasonal distribution of O\-3 was observed. O\-3 concentration was kept in a high level in autumn, and its formation was restrained in summer due to frequent thunderstorm and high humidity. The numerical simulation showed the average concentration and maximum concentration of O\-3 would increase 60%—100% if vehicular emission increased 100% in Guangzhou.

Effects of traffic pollution on the genetic structure of Poa annua L.populations

The genetic composition of Poa annua L. populations with a series of traffic pollution was studied by starch electrophoresis. Five enzyme systems were stained. The results showed that: (1) Traffic pollution can dramatically change genotypic frequencies at some loci of P. annua populations. Significant deviations from Hardy Weinberg equilibrium were observed on loci Fe 1 and Me due to the excess of heterozygotes in some populations. (2) The effective number of alleles per locus and the observed and expected heterozygosity were higher in the pollution series than in the clear control site(Botanic Park population), but the increase was not related with the pollution extent. (3) Most genetic variation was found within populations, and only 6 21% was among populations of the polluted series. Slightly higher differentiation( F ST =7 98%) was observed when the control population was included. (4) The calculated gene flow(Nm) is 2 8841 per generation. The mean of genetic identity is 0 9864 and the genetic distance average to 0 0138

Traffic Noise Pollution： Spectra Characteristics and Windows Sound Insulation in Laboratory and Field Measurements

The traffic spectra influence on indoor noise through windows is evaluated with laboratory and field measurements. Different traffic noise spectra were registered and reproduced, simulating the outdoor traffic conditions through different windows. Spectrum adaptation terms for the recorded spectra were different from the ones obtained from the Standards, showing that Normative gives a safe evaluation of the Weighted Sound Insulation Index. In field measurements, the level abatements calculated from the Facade Acoustic Insulation Index corrected with the adaptation terms shows that the ones from the Standard do not give a good approximation, while if the level abatements is calculated using the adaptation terms from the registered spectra, a more reliable approximation is achieved. Furthermore, comparing the level abatements for two windows having both Rw equal to 41 dB, very different values were obtained at different frequencies; therefore to characterize acoustic performances of windows, sound insulation curves are also needed. The correlation between the mean difference between adaptation terms calculated from the standard and the one between abatements obtained with pink noise and the ones obtained with the registered spectra is good, but different for road traffic and trains. In both, the difference diminishes when the difference between the abatements increases.

Asphalt fractions in airborne particles from highway traffic and the accumulation in plants

With reference to ASTM D4124, asphalt fractions, including polar aromatics (polars),naphthene aromatics (aromatics) and saturates,were characterized both in airborne particles collected in the distances of 2.0 -83.6m from the highway and in the plant samples (including grass,leaves and wheat straw) collected in the distance of 2.0 -10. 0m from the highway. In comparison to the results of diesel particulate, background plant samples and asphalt cernent samples from highway surface, it is concluded that there could be asphalt rnatters in airborne particles and asphalt makes the rnain contributions to the accumulation of the three factions mentioned above in plant species. In the ambient air,the concentrations of the three asphalt fractions are 0. 54- 3.06 ×10-3 mg polars,1. 77- 9. 50 × 10-4 mg aromatics and 0. 21- 1. 23 × 10-4 mg saturates for per cubic meter air. The percentage of bitumen in airborne particles is 1. 61%-11. 02%. In the plant samples, the concentrations are 0. 29- 3.07mg polars, 0.89- 3.89 aromatics and 0. 37-1. 53 mg saturates for per gram dry plant materials.

Effects of increasing the degree of building height asymmetry on ventilation and pollutant dispersion within street canyons

Rational urban design helps to build sustainable cities with high ventilation capacity and pollutant removal ca-pacity,but the effect of building height on ventilation and pollutant dispersion inside asymmetric canyons has not been fully studied.In this paper,we studied the effect of increasing the degree of building height asym-metry(DBHA)on canyon ventilation and pollutant diffusion in shallow and deep asymmetric street canyons by considering six different building height ratios(BHR=3/4,1/2,1/3,4/3,2/1 and 3/1).The results show that increasing the DBHA in asymmetric canyons can improve the ventilation and pollutant removal capacity.For step-up canyons,increasing the downwind building height is very useful to improve ventilation and pollutant re-moval.For shallow/deep step-up canyons with BHR=1/3,the air exchange rate(ACH)increased to 211.2%and 380.1%of the flat canyons,respectively.The spatially-average pollutant concentration in the pedestrian zones(leeward Kavg∗ang windward Kavg∗)decreases significantly with the increase of DBHA,especially for the deep step-up canyon with BHR=1/3,the leeward Kavg∗and windward Kavg∗decrease to 15.3%and 3%,respectively.Also,increasing the upwind building height can also improve the ventilation capacity in the step-down canyons.For the deep step-down canyon with BHR=3/1,the leeward Kavg∗and windward Kavg∗decreased to 40.6%and 24.1%of the deep flat canyon,respectively.Notably,the ventilation capacity is very low for step-down canyons with BHR=4/3,and for step-down canyons with BHR≥2/1,the ventilation capacity and pollutant removal capacity increase significantly with the increase of DBHA.Therefore,in urban planning,step-down canyons with BHR=4/3 should be avoided and designed to satisfy the condition of BHR≥2/1.These findings will be a valuable reference for urban designers to build sustainable cities with high ventilation capacity.

Study on the Layout of Urban Planning in Rapid Urbanization Areas under the Background of Air Pollution

China＇s urbanization has been over the medium-term process,which has made great achievements,but also triggered a huge problem of air pollution. Air pollution has become a big problem after the water pollution in China,and a serious threat to people＇s life and health. Under the background of ＂ the construction of beautiful China＂ and rapid urbanization,how to build a beautiful home has become the focus of attention. Taking Shenyang as an example,the author contrastively analyses the spatial distribution of the main air pollutants（ PM10,PM2. 5,and SO2） and the present situation of land use,and thus finds out the rules between pollutants distribution and land use. Then combining the urban planning scheme and the rules obtained above,reasonable suggestions are proposed for the scheme to improve the air quality,and reduce or avoid air pollution,and providing the basis for the construction of a piece of blue sky. The conclusions are as follows： 1 air pollutants concentration above Light Oil Gas Making Factory in south vice city of Shenyang reaches the peak value,and industrial point source is the main air pollutants emission source; 2 pollutants concentration above greenbelt is the lowest; 3 the overall spatial structure of urban planning can insulate the industrial agglomeration areas to some extent; greenbelt planning covers 40%- 50% of the area with high concentration of air pollutants,and it is suggested to achieve full coverage; traffic planning can achieve shunt most of the pollutants in many regions,but it can also expand the scope of pollutants in some certain regions,in such regions,it should reduce the road density.

Evaluating Market Benefits of Transportation Tunnels—The Carmel Tunnels as a Case Study

Since opening in 2010, The Carmel Tunnels have redirected some of the traffic from within the City of Haifa in Israel. This paper studies the direct and indirect financial and environmental benefits of the Carmel Tunnels compared to alternative routes. Di-rect benefits for drivers include financial savings thanks to savings on time and gas. Indirect benefits for drivers and for the public include reduced air pollution, green-house gas emissions and noise. Results show significant positive benefits from using the Carmel Tunnels compared to various alternative routes (i.e., reference scenarios). During peak hours (8 am and 4 pm), when there is heavy traffic on the alternative routes, the total benefits increase by about 25% - 47%. Using tunnels for transportation allows, among other benefits, efficient use of underground land, redirecting traffic congestion from town centers, decreasing landscape damage due to major roads passing through open spaces, and reducing air pollution in residential areas.

The effect of noise barriers on viaducts on pollutant dispersion in complex street canyons

The noise reduction effect of noise barriers has been extensively studied,but the effect on pollutant dispersion remains unclear.A computational fluid dynamics(CFD)simulation is conducted to investigate the effects of different heights,lengths,and types of noise barriers and different wind speeds on pollutant dispersion in street canyons with viaducts.The field synergy theory of the convective mass transfer process is used for quantitative analysis of pollutant dispersion in street canyons.The results show that as the height and length of the noise barrier increase,the pollutant dispersion capacity decreases.As the wind speed increases,the rate of decrease in the average CO concentration declines.The effect of the wind speed on the synergistic improvement of the speed and concentration gradient vectors differs for different types of noise barriers.The performance follows the order:fully-closed noise barrier>left noise barrier>right noise barrier>semi-closed noise barrier.The different noise barrier types significantly impact the flow field and pollutant dispersion and reduce the CO concentration to varying degrees,except for the fully-closed type.The average CO concentration in the pedestrian breathing zone is reduced by a maximum of 55.85%on the leeward side and by 53%on the windward side,indicating that an appropriate noise barrier on the viaduct reduces noise pollution and improves the air quality in street canyons,especially in the pedestrian breathing zone.

Variations in traffic-related polycyclic aromatic hydrocarbons in PM2.5 in Kanazawa, Japan, after the implementation of a new vehicle emission regulation

A three-year sampling campaign was conducted at a roadside air pollution monitoring station in the urban area of Kanazawa, Japan. Due to a new emission regulation, PAHs levels decreased over the sampling campaign, exhibiting values of 706 ± 413 pg/m^(3) in 2017, 559 ±384 pg/m^(3) in 2018, and 473 ± 234 pg/m^(3) in 2019. In each year, similar seasonal variations in PAHs levels were observed, with higher levels observed in winter and lower levels in summer. Among the PAHs isomer ratios, we observed that the ratio of benzo[b]fluoranthene(BbF) and benzo[k]fluoranthene(BkF), [Bb F]/([BbF] + [BkF]), and the ratio of indeno[1,2,3-cd]pyrene(IDP) and benzo[ghi]perylene(BgPe), [IDP]/([BgPe] + [IDP]), showed stability over the sampling campaign and were less affected by the new emission regulation, seasonal variations, and regional characteristics. When using the combined ratio ranges of 0.66-0.80([Bb F]/[BbF] + [BkF]) and 0.26-0.49([IDP]/[Bg Pe] + [IDP]), traffic emissions were clearly distinguished from other PAHs emission sources. Principal component analysis(PCA) and positive matrix factorization(PMF) were also performed to further analyse the characteristics of traffic-related PAHs. Overall, this study affirmed the effectiveness of the new emission regulation in the reduction of PAHs emissions and provided a combined range for identifying PAHs traffic emission sources.

A building-based data capture and data mining technique for air quality assessment

Recently,a building-based air quality model system which can predict air quality in front of individual buildings along both sides of a road has been developed.Using the Macao Peninsula as a case study,this paper shows the advantages of building-based model system in data capture and data mining.Compared with the traditional grid-based model systems with input/output spatial resolutions of 1-2 km,the building-based approach can extract the street configuration and traffic data building by building and therefore,can capture the complex spatial variation of traffic emission,urban geometry,and air pollution.The non-homogeneous distribution of air pollution in the Macao Peninsula was modeled in a highspatial resolution of 319 receptors·km^(-2).The spatial relationship among air quality,traffic flow,and urban geometry in the historic urban area is investigated.The study shows that the building-based approach may open an innovative methodology in data mining of urban spatial data for environmental assessment.The results are particularly useful to urban planners when they need to consider the influences of urban form on street environment.

Determination of 15 phthalate esters in air by gas-phase and particle-phase simultaneous sampling

Based on previous research, the sampling and analysis methods for phthalate esters （PAEs） were improved by increasing the sampling flow of indoor air from 1 to 4 L/min, shortening the sampling duration from 8 to 2 hr. Meanwhile, through the optimization of chromatographic conditions, the concentrations of 9 additional PAE pollutants in indoor air were measured. The optimized chromatographic conditions required a similar amount of time for analysis as before, but gave high responsivity, the capability of simultaneously distinguishing 15 kinds of PAEs, and a high level of discrimination between individual sample peaks, as well as stable peak generation. The recovery rate of all gas-phase and particle-phase samples of the 15 kinds of PAEs ranged from 91.26% to 109.42%, meeting the quantitative analysis requirements for indoor and outdoor air sampling and analysis. For the first time, investigation of the concentration levels as well as characteristics of 15 kinds of PAEs in the indoor air from four different traffic micro-environments （private vehicles, busses, taxis and subways） was carried out, along with validation of the optimized sampling and analytical method. The results show that all the 9 additional PAEs could be detected at relatively high pollution levels in the indoor air from the four traffic micro-environments. As none of the pollution levels of the 15 kinds of PAEs in the indoor air from the 4 traffic micro-environments should be neglected, it is of great significance to increase the types of PAEs able to be detected in indoor air.