Non-methane hydrocarbons source apportionment at different sites in Mexico City during 2002–2003

Abstract. The atmospheric concentrations of a variety of non-methane hydrocarbons (NMHC) collected at different sites, representing urban and rural environments within Mexico City Metropolitan Area (MCMA) during 1997, 2002 and 2003 field campaigns, were compared and used as an input for the Chemical Mass Balance (CMB) receptor model to determine the source contribution of NMHC to the atmosphere. A common feature at all the locations was the dominance of alkenes (59%), aromatics (16%) and olefins (9%) in the average NMHC burden. At the urban sites the interquartile range of NMHC concentrations showed stabilization over this period with a slight increase in the concentrations of propane and butanes in the southwest site of the MCMA in 2003 due to the increased use of liquefied petroleum gas (LPG). The receptor model CMB version 8.0 was used to apportion the NMHC sources at six locations within the MCMA, representing the heavily industrialized, commercial, residential and rural areas. For the 2003 field campaign, the contribution of vehicular emissions dominated the NMHC concentrations (19.7%±7.1% for gasoline vehicles and 35.4%±17.5% for diesel vehicles) followed by the emissions of marketing and handling of LPG (29.9%±8.0%). The NMHC concentrations showed a weekly cycle with the highest levels towards the end of the week and lowest at weekend and beginning of the week, suggesting that both emissions and accumulations process play a key role in building up NMHC levels. The toluene to benzene ratio was used to determine photochemical ageing of the air samples during the 2003 field campaign. The database was divided into periods with similar wind circulation pattern; the results suggest that ageing process within the MCMA is generally suppressed by the amount of fresh emissions.

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Characterizing Black Carbon Emissions from Gasoline, LPG, and Diesel Vehicles via Transient Chassis-Dynamometer Tests

Applied Sciences ◽

10.3390/app10175856 ◽

2020 ◽

Vol 10 (17) ◽

pp. 5856

Author(s):

Gyutae Park ◽

Kyunghoon Kim ◽

Taehyun Park ◽

Seokwon Kang ◽

Jihee Ban ◽

...

Keyword(s):

Black Carbon ◽

Coal Combustion ◽

Gasoline Direct Injection ◽

Environmental Research ◽

Particulate Filter ◽

Biomass Combustion ◽

Liquefied Petroleum Gas ◽

Chassis Dynamometer ◽

Diesel Vehicles ◽

Gasoline Vehicles

With global anthropogenic black carbon (BC) emissions increasing, automobiles are significantly contributing as the major source of emissions. However, the appropriate regulations of BC emissions from vehicles are not in place. This study examined BC emissions following fuel types (gasoline, liquefied petroleum gas (LPG), and diesel) and engine combustion (gasoline direct injection (GDI) and multi-port injection (MPI) for gasoline vehicles) with emission regulations. To this end, chassis dynamometer and aethalometer (AE33) were used. Driving modes created by the National Institute of Environmental Research (NIER) and emission certification modes (CVS-75 and NEDC) for vehicles in Korea were used to determine BC emissions for various vehicle speeds. In addition, the contributions of biomass and coal combustion to the data of AE33 were analyzed to determine the possibility of tracking the BC sources. MPI, LPG, and EURO 6 with diesel particulate filter (DPF) vehicles emitted the lowest BC emissions in NIER modes. Among gasoline vehicles, MPI vehicles showed the lower BC content in PM emissions. Also, older vehicles in MPI vehicles emitted the high PM and BC emissions. The BC emissions of EURO 3 vehicles without DPF were the highest as the results of previous studies, and it was found that as emissions regulations were tightened, the level of BC results of diesel vehicles became similar with MPI vehicles. The average absorption Ångström exponent (AAE) from difference emissions sources were biomass combustion (oak wood) > coal combustion (the power plant stack) > automobile emissions (gasoline, LPG, diesel).

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Receptor Model Source Apportionment of Nonmethane Hydrocarbons in Mexico City

The Scientific World JOURNAL ◽

10.1100/tsw.2002.147 ◽

2002 ◽

Vol 2 ◽

pp. 844-860 ◽

Cited By ~ 13

Author(s):

V. Mugica ◽

J. Watson ◽

E. Vega ◽

E. Reyes ◽

M.E. Ruiz ◽

...

Keyword(s):

Mexico City ◽

Motor Vehicle ◽

Ambient Air ◽

Nonmethane Hydrocarbons ◽

Receptor Model ◽

Liquefied Petroleum Gas ◽

Vehicle Exhaust ◽

Source Profiles ◽

Source Contributions ◽

Initial Source

With the purpose of estimating the source contributions of nonmethane hydrocarbons (NMHC) to the atmosphere at three different sites in the Mexico City Metropolitan Area, 92 ambient air samples were measured from February 23 to March 22 of 1997. Light- and heavy-duty vehicular profiles were determined to differentiate the NMHC contribution of diesel and gasoline to the atmosphere. Food cooking source profiles were also determined for chemical mass balance receptor model application. Initial source contribution estimates were carried out to determine the adequate combination of source profiles and fitting species. Ambient samples of NMHC were apportioned to motor vehicle exhaust, gasoline vapor, handling and distribution of liquefied petroleum gas (LP gas), asphalt operations, painting operations, landfills, and food cooking. Both gasoline and diesel motor vehicle exhaust were the major NMHC contributors for all sites and times, with a percentage of up to 75%. The average motor vehicle exhaust contributions increased during the day. In contrast, LP gas contribution was higher during the morning than in the afternoon. Apportionment for the most abundant individual NMHC showed that the vehicular source is the major contributor to acetylene, ethylene, pentanes, n-hexane, toluene, and xylenes, while handling and distribution of LP gas was the major source contributor to propane and butanes. Comparison between CMB estimates of NMHC and the emission inventory showed a good agreement for vehicles, handling and distribution of LP gas, and painting operations; nevertheless, emissions from diesel exhaust and asphalt operations showed differences, and the results suggest that these emissions could be underestimated.

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The application of drones for mosquito larval habitat identification in rural environments: a practical approach for malaria control?

Malaria Journal ◽

10.1186/s12936-021-03759-2 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Michelle C. Stanton ◽

Patrick Kalonde ◽

Kennedy Zembere ◽

Remy Hoek Spaans ◽

Christopher M. Jones

Keyword(s):

Image Analysis ◽

Malaria Control ◽

Rural Areas ◽

Near Infrared ◽

Aquatic Vegetation ◽

Temporal Trends ◽

Scale Up ◽

Larval Habitat ◽

Habitat Characteristics ◽

Rural Environments

Abstract Background Spatio-temporal trends in mosquito-borne diseases are driven by the locations and seasonality of larval habitat. One method of disease control is to decrease the mosquito population by modifying larval habitat, known as larval source management (LSM). In malaria control, LSM is currently considered impractical in rural areas due to perceived difficulties in identifying target areas. High resolution drone mapping is being considered as a practical solution to address this barrier. In this paper, the authors’ experiences of drone-led larval habitat identification in Malawi were used to assess the feasibility of this approach. Methods Drone mapping and larval surveys were conducted in Kasungu district, Malawi between 2018 and 2020. Water bodies and aquatic vegetation were identified in the imagery using manual methods and geographical object-based image analysis (GeoOBIA) and the performances of the classifications were compared. Further, observations were documented on the practical aspects of capturing drone imagery for informing malaria control including cost, time, computing, and skills requirements. Larval sampling sites were characterized by biotic factors visible in drone imagery and generalized linear mixed models were used to determine their association with larval presence. Results Imagery covering an area of 8.9 km2 across eight sites was captured. Larval habitat characteristics were successfully identified using GeoOBIA on images captured by a standard camera (median accuracy = 98%) with no notable improvement observed after incorporating data from a near-infrared sensor. This approach however required greater processing time and technical skills compared to manual identification. Larval samples captured from 326 sites confirmed that drone-captured characteristics, including aquatic vegetation presence and type, were significantly associated with larval presence. Conclusions This study demonstrates the potential for drone-acquired imagery to support mosquito larval habitat identification in rural, malaria-endemic areas, although technical challenges were identified which may hinder the scale up of this approach. Potential solutions have however been identified, including strengthening linkages with the flourishing drone industry in countries such as Malawi. Further consultations are therefore needed between experts in the fields of drones, image analysis and vector control are needed to develop more detailed guidance on how this technology can be most effectively exploited in malaria control.

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Interpretation of Atmospheric CO2 Measurements in Mexico City

10.5194/egusphere-egu21-15117 ◽

2021 ◽

Author(s):

Yang Xu ◽

Michel Ramonet ◽

Thomas Lauvaux ◽

Jinghui Lian ◽

Francois-Marie Bréon ◽

...

Keyword(s):

Mexico City ◽

Rural Areas ◽

Ghg Emissions ◽

Single Layer ◽

Urban Canopy ◽

Horizontal Resolution ◽

Complex Topography ◽

Urban Station ◽

Mountain Areas ◽

Mixing Ratios

The French-Mexican project Mexico City&#8217;s Regional Carbon Impacts (MERCI-CO2) is building a CO2 observation network in the Metropolitan Zone of the Valley of Mexico (ZMVM). The project investigates the atmospheric signals generated by the city's emissions on total column and surface measurements, aiming at reducing the uncertainties of CO2 emissions in ZMVM and evaluating the effects of policies that had been implemented by the city authorities.&#160;A nested high-resolution atmospheric transport simulation based on the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) is performed to analyze the observed CO2 mixing ratios during dry and wet seasons over Mexico City and its vicinity. Both anthropogenic emissions (UNAM 1-km fossil fuel emissions) and biogenic fluxes (CASA 5-km simulations) are taken into account. The model configuration, with a horizontal resolution of 1km and using the Single-Layer urban canopy Model (SLUCM), has been evaluated over two weeks in January 2018 using meteorological measurements from 26 stations set by the Air Quality Agency of Mexico City (Secretary of the Environment of Mexico City - SEDEMA). The reconstruction of meteorological conditions in the urban area shows better performances than suburban and mountainous areas. Due to the complex topography, wind speeds in mountain areas are 2-3 m/s over estimated and wind direction simulations in some stations are 90&#176; deflected, especially in southern mountains.&#160;Two high-precision CO2 analyzers deployed in urban and rural areas of Mexico City are used to evaluate the WRF CO2 1-km simulations. The model reproduced the diurnal cycle of CO2 mixing ratios at the background station but under-estimates the nighttime accumulation at the urban station. Mean absolute errors of CO2 concentrations range from 6.5 ppm (background station) to 27.1 ppm (urban station), mostly driven by the elevated nocturnal enhancements (up to 500 ppm at UNAM station). Based on this analysis, we demonstrate the challenges and potential of mesoscale modeling over complex topography, and the potential use of mid-cost sensors to constrain the urban GHG emissions of Mexico City.

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Damage assessment mapping of rural environments; integration of SAR and Optical data

10.5194/egusphere-egu21-9202 ◽

2021 ◽

Author(s):

Shiran Havivi ◽

Stanley R. Rotman ◽

Dan G. Blumberg ◽

Shimrit Maman

Keyword(s):

Natural Disaster ◽

Rural Areas ◽

Urban Areas ◽

Damage Assessment ◽

Vegetation Index ◽

Urban Environments ◽

Optical Data ◽

Damage Level ◽

Rural Environments ◽

Rural And Urban

The damage caused by a natural disaster in rural areas differs in nature, extent, landscape and in structure, from the damage in urban environments. Previous and current studies focus mainly on mapping damaged structures in urban areas after catastrophe events such as an earthquake or tsunami. Yet, research focusing on the damage level or its distribution in rural areas is absent. In order to apply an emergency response and for effective disaster management, it is necessary to understand and characterize the nature of the damage in each different environment.&#160;Havivi et al. (2018), published a damage assessment algorithm that makes use of SAR images combined with optical data, for rapid mapping and compiling a damage assessment map following a natural disaster. The affected areas are analyzed using interferometric SAR (InSAR) coherence. To overcome the loss of coherence caused by changes in vegetation, optical images are used to produce a mask by computing the Normalized Difference Vegetation Index (NDVI) and removing the vegetated area from the scene. Due to the differences in geomorphological settings and landuse\landcover between rural and urban settlements, the above algorithm is modified and adjusted by inserting the Modified Normalized Difference Water Index (MNDWI) to better suit rural environments and their unique response after a disaster. MNDWI is used for detection, identification and extraction of waterbodies (such as irrigation canals, streams, rivers, lakes, etc.), allowing their removal which causes lack of coherence at the post stage of the event. Furthermore, it is used as an indicator for highlighting prone regions that might be severely affected pre disaster event. Thresholds are determined for the co-event coherence map (&#8804; 0.5), the NDVI (&#8805; 0.4) and the MNDWI (&#8805; 0), and the three layers are combined into one. Based on the combined map, a damage assessment map is generated.&#160;As a case study, this algorithm was applied to the areas affected by multi-hazard event, following the Sulawesi earthquake and subsequent tsunami in Palu, Indonesia, which occurred on September 28th, 2018. High-resolution COSMO-SkyMed images pre and post the event, alongside a Sentinel-2 image pre- event are used as inputs. The output damage assessment map provides a quantitative assessment and spatial distribution of the damage in both the rural and urban environments. The results highlight the applicability of the algorithm for a variety of disaster events and sensors. In addition, the results enhance the contribution of the water component to the analysis pre and post the event in rural areas. Thus, while in urban regions the spatial extent of the damage will occur in its proximity to the coastline or the fault, rural regions, even in significant distance will experience extensive damage due secondary hazards as liquefaction processes.&#160; &#160; &#160;

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Impact of the Mobility Restrictions in the Palestinian Territory on the Population and the Environment

Sustainability ◽

10.3390/su132313457 ◽

2021 ◽

Vol 13 (23) ◽

pp. 13457

Author(s):

Hala Aburas ◽

Isam Shahrour

Keyword(s):

Energy Consumption ◽

Quantitative Analysis ◽

Literature Review ◽

Co2 Emissions ◽

Average Value ◽

Diesel Vehicles ◽

Mobility Barriers ◽

Gasoline Vehicles ◽

Palestinian Territory ◽

The Impact

This paper analyzes the mobility restrictions in the Palestinian territory on the population and the environment. The literature review shows a scientific concern for this issue, with an emphasis on describing mobility barriers and the severe conditions experienced by the population due to these barriers as well as the impact of mobility restrictions on employment opportunities. On the other hand, the literature review also shows a deficit in quantitative analysis of the effects of mobility restrictions on the environment, particularly on energy consumption and greenhouse gas emissions. This paper aims to fill this gap through a quantitative analysis by including data collection about mobility restrictions, using network analysis to determine the impact of these restrictions on inter-urban mobility, and analysis of the resulting energy consumption and CO2 emissions. The results show that mobility restrictions induce a general increase in energy consumption and CO2 emissions. The average value of this increase is about 358% for diesel vehicles and 275% for gasoline vehicles.

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Sources and transformations of particle-bound polycyclic aromatic hydrocarbons in Mexico City

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-12741-2005 ◽

2005 ◽

Vol 5 (6) ◽

pp. 12741-12773 ◽

Cited By ~ 9

Author(s):

L. C. Marr ◽

K. Dzepina ◽

J. L. Jimenez ◽

F. Reisen ◽

H. L. Bethel ◽

...

Keyword(s):

Mass Spectrometry ◽

Polycyclic Aromatic Hydrocarbons ◽

Mexico City ◽

Aromatic Hydrocarbons ◽

Heterogeneous Reactions ◽

Field Campaign ◽

Aerosol Mass ◽

Aerosol Mass Spectrometry ◽

Polycyclic Aromatic ◽

First Time

Abstract. Understanding sources, concentrations, and transformation of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere is important because of their potent mutagenicity and carcinogenicity. The measurement of particle-bound PAHs by three different methods during the Mexico City Metropolitan Area field campaign in April 2003 presents a unique opportunity for characterization of these compounds and assessment of the methods. The three methods are (1) collection and analysis of bulk samples for time-integrated gas- and particle-phase speciation by gas chromatography/mass spectrometry; (2) aerosol photoionization for fast detection of PAHs on particles' surfaces; and (3) aerosol mass spectrometry for fast analysis of size and chemical composition. This research represents the first time aerosol mass spectrometry has been used to measure ambient PAH concentrations and the first time that fast, real-time methods have been used to quantify PAHs alongside traditional filter-based measurements in an extended field campaign. Speciated PAH measurements suggest that motor vehicles and garbage and wood burning are important sources in Mexico City. The diurnal concentration patterns captured by aerosol photoionization and aerosol mass spectrometry are generally consistent. Ambient concentrations typically peak at ~110 ng m−3 during the morning rush hour and rapidly decay due to changes in source activity patterns and dilution as the boundary layer rises, although surface-bound PAH concentrations decay faster. The more rapid decrease in surface versus bulk PAH concentrations during the late morning suggests that freshly emitted combustion-related particles are quickly coated by secondary aerosol material in Mexico City's atmosphere and may also be transformed by heterogeneous reactions.

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Life Patterns and Social Differentiation in Late Colonial México City

Estudios de Historia Novohispana ◽

10.22201/iih.24486922e.1991.011.3340 ◽

1991 ◽

Vol 11 (011) ◽

Cited By ~ 1

Author(s):

John E. Kicza

Keyword(s):

Mexico City ◽

Rural Areas ◽

Spanish Empire ◽

Colonial Mexico ◽

The Political ◽

Economic Activities ◽

Life Patterns ◽

Production And Consumption ◽

The Social ◽

Regional Centers

Mexico City, in the fifty years between 1770 and 1820 was far and away the largest urban entity in the Americas, with a population ranging between about 80000 and 120000 peop1e in this period. As a center of both production and consumption and the headquarters of the numerous agencies in the political and religious hierarchies, the capital had a major impact on the social organization and economic activities of rural areas and regional centers throughout the colony of New Spain. In its capacity as a mercantile entrepôt of the most prosperous colony in the Spanish empire at this time, Mexico City's reach extended across half the globe, with its merchants directing operations and interchanges from at least Manila -and by extension China- to Spain -and by extension England.

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A comparison of foraging by Eptesicus fuscus (Chiroptera: Vespertilionidae) in urban and rural environments

Canadian Journal of Zoology ◽

10.1139/z85-040 ◽

1985 ◽

Vol 63 (2) ◽

pp. 263-266 ◽

Cited By ~ 68

Author(s):

J. F. Geggie ◽

M. B. Fenton

Keyword(s):

Rural Areas ◽

Urban Areas ◽

Eptesicus Fuscus ◽

Urban Setting ◽

Foraging Activity ◽

Radio Tracking ◽

Urban Habitats ◽

Rural Environments ◽

Rural And Urban ◽

Time Away

We compared the foraging activity of populations of Eptesicus fuscus in rural and urban settings in eastern Ontario and western Quebec by monitoring their echolocation calls and by radio tracking individuals during the summer of 1980. Foraging was detected in all of the rural and urban habitats we monitored. There were no significant differences in the levels of foraging activity over different urban habitats, but the overall foraging rates were significantly higher in the rural than in the urban areas. Foraging in rural areas was significantly higher in residential zones and over water and was less common in parkland and farmland. Bats in rural areas foraged among aggregations of insects at lights, a pattern of behaviour not seen among urban bats. Differences in foraging rates and the fact that rural bats spent significantly less time away from their roosts suggest that prey density was lower in the urban setting. Although urban habitats appear to provide E. fuscus with a wealth of roosting sites, food supplies are lower there.

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Criminal Investigation in Rural Areas: How Police Detectives Manage Remoteness and Resource Scarcity1

Policing A Journal of Policy and Practice ◽

10.1093/police/paaa023 ◽

2020 ◽

Cited By ~ 1

Author(s):

Oscar Rantatalo ◽

Ola Lindberg ◽

Markus Hällgren

Keyword(s):

Rural Areas ◽

Ethnographic Study ◽

Criminal Investigation ◽

Northern Sweden ◽

Daily Work ◽

Police Investigations ◽

Trade Offs ◽

Rural Environments ◽

Urban Rural ◽

Set Up

Abstract This article addresses how rural environments characterized by remoteness impact the work of police detectives in their casework. It reports on an ethnographic study of two investigative departments (working on volume crime and domestic crime) located in Northern Sweden. Interviews (N = 27) and participant observations (N = 56) were conducted in order to examine how investigators approached and managed rural conditions in their daily work. Findings indicate that police investigations in rural areas are characterized by constraints, such as resource shortages, extended set-up times (due to travelling), and challenges in multitasking. The findings identify two main practices for investigating crime in such settings: ‘rural investigation’ that entails a decentralized approach in which investigators are embedded locally; and ‘investigating the rural’ that entails a distanced, centralized approach. This article discusses trade-offs and predicted outcomes in crime investigation and highlights how the urban/rural binary divide encompasses a paradoxical tension that investigators must manage continuously.

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