Air Pollution In Metropolitan Area Research Articles

Short-Term Associations between Morbidity and Air Pollution in Metropolitan Area of Monterrey, Mexico

Short-term effects of air pollution on the number of hospital admissions in eight municipalities of the Metropolitan Area of Monterrey, Mexico, were assessed from 2016 to 2019 using a time-series approach. Air quality data were obtained from the Atmospheric Monitoring System of Nuevo Leon State (SIMA) which belongs to SINAICA (National System of Air Quality Information), providing validated data for this study. Epidemiological data were provided by SINAIS (National System of Health Information), considering admission by all causes and specific causes, gender and different age groups. Guadalupe had the highest mean concentrations for SO2, CO and O3; whereas Santa Catarina showed the highest NO2 concentrations. Escobedo and Garcia registered the highest levels for PM10. Only PM10 and O3 exceeded the permissible maximum values established in Mexican official standards. A basal Poisson model was constructed to assess the association between daily morbidity and air pollutants, from this, a second scenario in which daily mean concentrations of air pollutant criteria increase by 10% was considered. Most of pollutants and municipalities studied showed a great number of associations between an increase of 10% in their current concentrations and morbidity, especially for the age group between 5 and 59 years during cold months, excepting ozone which showed a strongest correlation during summer. Results were comparable to those reported by other authors around the world, however, in spite of relative risk index (RRI) values being low, they are of public concern. This study demonstrated that considering the nature of their activities, economically active population and students, they could be more vulnerable to air pollution effects. Results found in this study can be used by decision makers to develop public policies focused on protecting this specific group of the population in metropolitan areas in Mexico.

Quantifying the air quality and health benefits of greening freight movements

Commercial vehicle movements have a large effect on traffic-related air pollution in metropolitan areas. In the Greater Toronto and Hamilton Area (GTHA), commercial vehicles include large and medium diesel trucks as well as light-duty gasoline-fuelled trucks. In this study, the emissions of various air pollutants associated with diesel commercial vehicles were estimated and their impacts on urban air quality, population exposure, and public health were quantified. Using data on diesel trucks in the GTHA and a chemical transport model at a spatial resolution of 1 km2, the contribution of commercial diesel movements to air quality was estimated. This contribution amounts to about 6–22% of the mean population exposure to nitrogen dioxide (NO2) and black carbon (BC), depending on the municipality, but is systematically lower than 3% for fine particulate matter (PM2.5) and ozone (O3). Using a comparative risk assessment approach, we estimated that the emissions of all diesel commercial vehicles within the GTHA are responsible for an annual total of at least 9810 Years of Life Lost (YLL), corresponding to $3.2 billion of annual social costs. We also assessed the impact of decreasing freeway-sourced diesel emissions along Highway 401, one of the busiest highways in North America. This is comparable with a removal of 250 to 1000 diesel trucks per day along that corridor, which could be replaced by alternative technologies. The mean NO2 and BC exposures of the population living within 500 m of the highway would decrease by 9% and 11%, respectively, with reductions as high as 22%. Such a measure would save 1310 YLL annually, equivalent to $428 million in social benefits.

Laboratory Performance Evaluation of Co-Polymer Based Dust Suppressant Mixed with Poorly Sand

Fugitive dust, generated along unpaved roads or uncovered construction sites, defined as a type of atmospheric matter (PM), is considered as a major source of air pollution in metropolitan areas. Fugitive dust can potentially cause respiratory illness and lung damage for humans, and even lead to premature death in sensitive individuals. Aiming to reduce the fugitive dust emission on unpaved roads, scientists did various lab experiences to analyse the performance of different types of dust suppressants mixed with different soils. In our previous papers, we evaluated the co-polymer-based dust suppressant (CPS) mixed with loamy sand (soils are from Sedona, Arizona) and silty clay (SP-SC) (soils are from Flagstaff, Arizona). The objective of this paper is to analyse the efficiency of fugitive dust reduction and present the quantitative laboratory evaluation of CPS mixed with poorly sand (SP). The soils were sampled from Page, Arizona. Soil classification is based on United Soil Classification System (USCS). Four concentrations of CPS (0%, 1%, 3%, and 5% by weight) were diluted and mixed with soil samples to prepared soil specimens. A series of laboratory experiences were performed on the soil specimens including moisture retention test, surface strength test, dynamic rolling test, and scanning electron microscopy (SEM) imaging. The laboratory results show that the higher the concentration of CPS is, the better CPS performs, and CPS with 5% concentration by weight controls the dust emissions better as compared with the other three concentrations, provided the results from the moisture retention rate, surface strength, dynamic rolling resistance, and interlock/cohesion effect in SEM images are promising.

Spatiotemporal model for estimating electric vehicles adopters

The use of fossil fuel vehicles is one of the factors responsible for the degradation of air quality in urban areas. In order to reduce levels of air pollution in metropolitan areas, several countries have encouraged the use of electric vehicles in the cities. However, due to the high investment costs in this class of vehicles, it is expected that the spatial distribution of electric vehicles' adopters will be heterogeneous. The additional charging power required by electric vehicles' batteries can change operation and expansion planning of power distribution utilities. In addition, urban planning agencies should analyze the most suitable locations for the construction of electric vehicle recharging stations. Thus, in order to provide information for the planning of electric mobility services in the city, this paper presents a spatiotemporal model for estimating the rate of electric vehicles' adopters per subareas. Results are spatial databases that can be viewed in geographic information systems to observe regions with greater expectancy of residential electric vehicle adopters. These outcomes can help utilities to develop new services that ground on the rising availability of electric mobility in urban zones.

Co-inoculation of Arizona cypress with arbuscular mycorrhiza fungi and Pseudomonas fluorescens under fuel pollution.

Air pollution in metropolitan areas of Iran has negatively impacted establishment, growth, and development of many woody plant species, threatening the health of urban forest species. This study was designed to investigate the effects of artificial inoculation of seedlings of a major urban forest tree, Arizona cypress (Cupressus arizonica Greene) with beneficial microorganisms under the stress of air pollution caused by exhaust emissions from fuel pollutants (FP). We conducted this research as a completely randomized design in a form of split-factorial with three factors comprising arbuscular mycorrhizal fungi (AMF) inoculation with Rhizophagus irregularis or Funneliformis mosseae or a mixture of both species, bacterial inoculation with Pseudomonas fluorescens and non-inoculated controls, and two levels of FP (fuel pollutants and non-fuel pollutants) using three replications of each treatment. Fuel pollutants significantly reduced root colonization, shoot and root dry weight, nutrient concentrations (N, P, K, and Fe), glomalin-related soil protein (GRSP), and chlorophyll concentration, while increasing proline content, enzyme activity, malondialdehyde (MDA), and hydrogen peroxide (H2O2) concentrations in Arizona cypress seedlings. Nevertheless, adverse effects of FP in the inoculated plants (especially AMF plants) were less than in the non-inoculated plants. Inoculations of AMF especially the mixture of both mycorrhizal species effectively alleviated the negative effects of FP on Arizona cypress seedlings. This promising effect was related to increased GRSP content in the media which improved concentrations of N, P, and Fe in plants, enhanced chlorophyll concentration, and elevated enzymatic antioxidants such as ascorbate peroxidase and glutathione peroxidase which resulted in increased dry mass of the plants under air pollution stress.

Urban Air Pollution in Taiwan before and after the Installation of a Mass Rapid Transit System.

Urbanization causes air pollution in metropolitan areas, coupled with meteorological factors that affect air quality. Although previous studies focused on the relationships of urbanization, air pollution, and climate change in Western countries, this study evaluated long-term variations of air quality and meteorological factors in Taiwanese metropolitan areas (Taipei area, Taichung City, and Kaohsiung City) and a rural area (Hualien County) between 1993 and 2012. The influence of a mass rapid transit (MRT) system on air quality was also evaluated. Air pollutant concentrations and meteorology data were collected from Taiwan Environmental Protection Administration (TEPA) air monitoring stations and Central Weather Bureau stations in the surveyed areas, respectively. Analyses indicate that levels of air pollution in metropolitan areas were greater than in the rural area. Kaohsiung City had the highest levels of O, SO, and particulate matter 2.5 or 10 µm in diameter (PM and PM). Clear downward trends for CO, NO, PM, PM, and especially SO concentrations were found in the surveyed areas, whereas O showed no decrease. Both O and PM concentrations showed similar bimodal seasonal distributions. Taiwan's air quality has improved significantly since 1993, indicating the effectiveness of promoting air pollution strategies and policies by the TEPA. Air pollution had an obvious improvement in Taipei area after the MRT system began operations in 1996. Because global climate may potentially affect urban air pollution in Taiwan, further study to clarify the mechanisms by which air pollution may affect human health and other biological effects is warranted.

An examination of population exposure to traffic related air pollution: Comparing spatially and temporally resolved estimates against long-term average exposures at the home location

Air pollution in metropolitan areas is mainly caused by traffic emissions. This study presents the development of a model chain consisting of a transportation model, an emissions model, and atmospheric dispersion model, applied to dynamically evaluate individuals’ exposure to air pollution by intersecting daily trajectories of individuals and hourly spatial variations of air pollution across the study domain. This dynamic approach is implemented in Montreal, Canada to highlight the advantages of the method for exposure analysis. The results for nitrogen dioxide (NO2), a marker of traffic related air pollution, reveal significant differences when relying on spatially and temporally resolved concentrations combined with individuals’ daily trajectories compared to a long-term average NO2 concentration at the home location. We observe that NO2 exposures based on trips and activity locations visited throughout the day were often more elevated than daily NO2 concentrations at the home location. The percentage of all individuals with a lower 24-hour daily average at home compared to their 24-hour mobility exposure is 89.6%, of which 31% of individuals increase their exposure by more than 10% by leaving the home. On average, individuals increased their exposure by 23-44% while commuting and conducting activities out of home (compared to the daily concentration at home), regardless of air quality at their home location. We conclude that our proposed dynamic modelling approach significantly improves the results of traditional methods that rely on a long-term average concentration at the home location and we shed light on the importance of using individual daily trajectories to understand exposure.

Preliminary study to explore gene-PM2.5 interactive effects on respiratory system in traffic policemen.

Traffic-related particulate matter (PM) is one of the major sources of air pollution in metropolitan areas. This study is to observe the interactive effects of gene and fine particles (particles smaller than 2.5 μm - PM2.5) on the respiratory system and explore the mechanisms linking PM2.5 and pulmonary injury. The participants include 110 traffic policemen and 101 common populations in Shanghai, China. Continuous 24 h individual-level PM2.5 is detected and the pulmonary function, high-sensitivity C-reactive protein (hs-CRP), Clara cell protein 16 (CC16) and the polymorphism in CXCL3, NME7 and C5 genes are determined. The multiple linear regression method is used to analyze the association between PM2.5 and health effects. Meanwhile, the interactive effects of gene and PM2.5 on lung function are analyzed. The individual PM2.5 exposure for traffic policemen was higher than that in the common population whereas the forced expiratory volume in 1 s (FEV1), the ratio of FEV1 to forced vital capacity (FEV1/FVC) and lymphocytes are lower. In contrast, the hs-CRP level is higher. In the adjusted analysis, PM2.5 exposure was associated with the decrease in lymphocytes and the increase in hs-CRP. The allele frequencies for NME7 and C5 have significant differences between FEV1/FVC ≤ 70% and FEV1/FVC > 70% participants. The results didn't find the interaction effects of gene and PM2.5 on FEV1/FVC in all the 3 genes. The results indicated that traffic exposure to high levels of PM2.5 was associated with systemic inflammatory response and respiratory injury. Traffic policemen represent a high risk group suffering from the respiratory injury.

Increase of diesel car raises health risk in spite of recent development in engine technology.

Diesel exhaust particles (DEP) contain elemental carbon, organic compounds including Polyaromatic hydrocarbons (PAHs), metals, and other trace compounds. Diesel exhaust is complex mixture of thousands of chemicals. Over forty air contaminants are recognized as toxicants, such as carcinogens. Most diesel exhaust particles have aerodynamic diameters falling within a range of 0.1 to 0.25 μm. DEP was classified as a definite human carcinogen (group 1) by the International Agency for Research on Cancer at 2012 based on recently sufficient epidemiological evidence for lung cancer. Significant decreases in DEP and other diesel exhaust constituents will not be evident immediately, and outworn diesel car having longer mileage still threatens health of people in spite of recent remarkable development in diesel engine technology. Policy change in South Korea, such as introduction of diesel taxi, may raise health risk of air pollution in metropolitan area with these limitations of diesel engine. To protect people against DEP in South Korea, progressive strategies are needed, including disallowance of diesel taxi, more strict regulation of diesel engine emission, obligatory diesel particulate filter attachment in outworn diesel car, and close monitoring about health effects of DEP.

Impact of traffic volume and composition on the air quality and pedestrian exposure in urban street canyon

Vehicle emissions are identified as a major source of air pollution in metropolitan areas. Emission control programs in many cities have been implemented as part of larger scale transport policy interventions to control traffic pollutants and reduce public health risks. These interventions include provision of traffic-free and low emission zones and congestion charging. Various studies have investigated the impact of urban street configurations, such as street canyon in urban centers, on pollutants dispersion and roadside air quality. However, there are few investigations in the literature to study the impact of change of fleet composition and street canyon effects on the on-road pollutants concentrations and associated roadside pedestrian exposure to the pollutants. This study presents an experimental investigation on the traffic related gas and particle pollutants in and near major streets in one of the most developed business districts in Hong Kong, known as Central. Both street canyon and open roadway configurations were included in the study design. Mobile measurement techniques were deployed to monitor both on-road and roadside pollutants concentrations at different times of the day and on different days of a week. Multiple traffic counting points were also established to concurrently collect data on traffic volume and fleet composition on individual streets. Street canyon effects were evident with elevated on-road pollutants concentrations. Diesel vehicles were found to be associated with observed pollutant levels. Roadside black carbon concentrations were found to correlate with their on-road levels but with reduced concentrations. However, ultrafine particles showed very high concentrations in roadside environment with almost unity of roadside/on-road ratios possibly due to the accumulation of primary emissions and secondary PM formation. The results from the study provide useful information for the effective urban transport design and bus route reorganization to minimize the impact of traffic emissions on the urban air quality and public health. Observations on the elevated ultrafine particle concentrations in roadside pedestrian levels also demonstrate the urgent need to improve roadside air quality to reduce pedestrians’ health risks especially inside street canyon.

Experimental assessment of the energy consumption of urban rail vehicles during stabling hours: Influence of ambient temperature

Urban rail has widely recognised potential to reduce congestion and air pollution in metropolitan areas, given its high capacity and environmental performance. Nevertheless, growing capacity demands and rising energy costs may call for significant energy efficiency improvements in such systems. Energy consumed by stabled rolling stock has been traditionally overlooked in the scientific literature in favour of analysing traction loads, which generally account for the largest share of this consumption. Thus, this paper presents the methodology and results of an experimental investigation that aimed to assess the energy use of stabled vehicles in the Tyne and Wear Metro system (UK). It is revealed that approximately 11% of the rolling stock's total energy consumption is due to the operation of on-board auxiliaries when stabled, and investigation of these loads is therefore a worthwhile exercise. Heating is responsible for the greatest portion of this energy, and an empirical correlation between ambient temperature and power drawn is given. This could prove useful for a preliminary evaluation of further energy saving measures in this area. Even though this investigation focused on a particular metro system in a relatively cold region, its methodology may also be valid for other urban and main line railways operating in different climate conditions.

LNG차량용 연료탱크의 지지시스템 구조해석에 관한 연구

Recently the LNG(liquified natural gas) public buses have been introduced to prevent the air pollution in metropolitan areas. As the LNG temperature in fuel tank is as low as -162℃, the thermal and structural effects of tank components need to be studied for safe introduction in the market. Especially the support system of LNG fuel tank in vehicle, which has connected with inside and outside of tanks, should put attention to reduce the structural stress due to cryogenic temperature and to restrict the heat flux from ambient. There are two supporting systems in the tank, that one is connected between inside and outside tanks by welding, and the other is the inserted support system which is a cylindrical SUS bar inserted in a hole of the supporting plate. In this study the temperature distribution and thermal stress of the inserted support system were evaluated by using the utility program as ANSYS. The results showed that the rate of heat transfer to inner tank through this support system was quite small due to limited contact of support bar with plate, but the thermal stress of support plate was obtained beyond the limited tensile value of SUS304. The cautious design for the support plate part, therefore, should be given to make the safe support system of LNG vehicle fuel tank.

Association Between Outdoor Air Pollution and Childhood Asthma Symptoms in Metropolitan Areas, United States

P-079 Introduction: Poor asthma outcomes have been linked to air pollution exposure in many studies focusing on local areas and/or short exposure duration. To assess the association between chronic outdoor air pollution exposure and asthma symptoms among children in metropolitan areas in the United States, air monitoring data from the U.S. Environmental Protection Agency (EPA) were merged with data from the National Health Interview Survey (NHIS). Methods: Annual average air pollutant levels for five criteria pollutants (particulate matter, ozone, sulfur dioxide, nitrogen dioxide, and carbon monoxide) were compiled by county for 2000–2003. The sample children in the study were ages 3–17 years residing in U.S. metropolitan areas for whom health conditions were reported in the 2001–2004 NHIS. Data for sample children were matched with exposure data for the previous 12 months when available for the county where they resided at the time of the NHIS interview. County-level pollutant values were ranked into quartiles. Logistic regression using survey sample weights was used to assess association between asthma outcomes (current asthma, recent asthma attack, and recent emergency room visit for asthma) and monitored air pollutant levels. Results: After adjusting for race/ethnicity, sex, parental education, poverty status, central city residence, and single parent household, the authors found that children living in the counties in the highest quartiles for all pollutants except carbon monoxide were generally more likely to have current asthma, a reported asthma attack in the previous 12 months, and a reported asthma emergency room visit in the previous 12 months than those residing in counties with pollution values ranked in the lower quartiles. For example, for children living in the highest quartile of pollution levels for particulate matter (aerodynamic diameter less than or equal to 2.5 micrometers), the adjusted odds ratio for current asthma was 1.53 (95% confidence interval [CI]: 1.06–2.23), for recent asthma attack 1.38 (95% CI: 0.95–2.01), and for asthma emergency room visit 1.73 (95% CI: 1.01–2.97). Conclusion: This analysis suggests that chronic exposure to air pollution in metropolitan areas throughout the U.S. may be associated with increased current asthma rates and ongoing asthma symptoms among children.

Lung Cancer Risk Assessment in Relation With Personal Exposure to Airborne Particles in Four French Metropolitan Areas

The objective of this study was to quantify the total number of lung cancer deaths attributable to chronic exposure to fine particles (pm2.5) among adult populations of four French urban populations (Grenoble, Rouen, Paris, and Strasbourg). A geographic information system (GIS) was used to extrapolate personal average exposures to the total population of each metropolitan area across three sectors contrasted in terms of local sources of pollutants. We followed a health impact assessment approach by using the risk estimates in the CSP II study. The annual number of lung cancer cases attributable to pm2.5 chronic exposure ranged from 12 to 404 according to the city. Among these deaths, up to 60% occurred, in the Paris metropolitan area in the urban sector most exposed to traffic emissions. The health impact of chronic exposures to urban air pollution in metropolitan areas of developed countries warrants further efforts to abate sources of toxicants and to reduce exposure. Traffic emissions still contribute significantly to the total lung cancer burden in France.

Goal Conflicts in Political Decisionmaking: A Survey of Municipality Politicians' Views of Road Pricing

An ongoing discussion concerns road-pricing schemes as measures to abate traffic congestion and air pollution in metropolitan areas. If such measures are to be effective, road-pricing fees must be set sufficiently high However, municipalities are likely to have other goals besides reducing car use, such as upholding fairness among citizens and financial goals such as creating revenues. If conflicts prove to exist between different goals, road-pricing schemes are not likely to achieve the environmental goal. To investigate the degree to which these goal conflicts exist, members of the local governments in the three major metropolitan areas of Sweden responded to a survey questionnaire. In the questionnaire they rated a number of principles guiding the setting of road-pricing fees hypothesized to correspond to the three goals. The results showed that, for the political majority, the hypothesized goal conflicts existed in that no single goal was optimized. It is concluded that in particular fairness may prevent road pricing achieving the environmental goal.

Development of a GIS-based urban air quality modelling system for transport-related pollution

In recent years motor vehicles have become the dominant source of air pollution in metropolitan areas. Hence, the assessment of transport-related air quality is of major concern to policymakers and municipal planners. This paper describes an urban air quality modelling system for evaluating the environmental effects of transport related air pollution. A preliminary evaluation of the model has been performed for one site in Dublin using data from an extensive monitoring and measuring campaign. Observed pollutant concentrations compare well with predicted concentrations using local conditions, e.g. site geometry, traffic activity, meteorology, and vehicle population.