Morphometric Differences in Testicular Tissue of Tadarida brasiliensis Bats from the Urban Area of Mexico City During Summer, Autumn, and Winter

Abstract. Organic aerosol concentrations are simulated using the WRF-CHEM model in Mexico City during the period from 24 to 29 March in association with the MILAGRO-2006 campaign. Two approaches are employed to predict the variation and spatial distribution of the organic aerosol concentrations: (1) a traditional 2-product secondary organic aerosol (SOA) model with non-volatile primary organic aerosols (POA); (2) a non-traditional SOA model including the volatility basis-set modeling method in which primary organic components are assumed to be semi-volatile and photochemically reactive and are distributed in logarithmically spaced volatility bins. The MCMA (Mexico City Metropolitan Area) 2006 official emission inventory is used in simulations and the POA emissions are modified and distributed by volatility based on dilution experiments for the non-traditional SOA model. The model results are compared to the Aerosol Mass Spectrometry (AMS) observations analyzed using the Positive Matrix Factorization (PMF) technique at an urban background site (T0) and a suburban background site (T1) in Mexico City. The traditional SOA model frequently underestimates the observed POA concentrations during rush hours and overestimates the observations in the rest of the time in the city. The model also substantially underestimates the observed SOA concentrations, particularly during daytime, and only produces 21% and 25% of the observed SOA mass in the suburban and urban area, respectively. The non-traditional SOA model performs well in simulating the POA variation, but still overestimates during daytime in the urban area. The SOA simulations are significantly improved in the non-traditional SOA model compared to the traditional SOA model and the SOA production is increased by more than 100% in the city. However, the underestimation during daytime is still salient in the urban area and the non-traditional model also fails to reproduce the high level of SOA concentrations in the suburban area. In the non-traditional SOA model, the aging process of primary organic components considerably decreases the OH levels in simulations and further impacts the SOA formation. If the aging process in the non-traditional model does not have feedback on the OH in the gas-phase chemistry, the SOA production is enhanced by more than 10% compared to the simulations with the OH feedback during daytime, and the gap between the simulations and observations in the urban area is around 3 μg m−3 or 20% on average during late morning and early afternoon, within the uncertainty from the AMS measurements and PMF analysis. In addition, glyoxal and methylglyoxal can contribute up to approximately 10% of the observed SOA mass in the urban area and 4% in the suburban area. Including the non-OH feedback and the contribution of glyoxal and methylglyoxal, the non-traditional SOA model can explain up to 83% of the observed SOA in the urban area, and the underestimation during late morning and early afternoon is reduced to 0.9 μg m−3 or 6% on average. Considering the uncertainties from measurements, emissions, meteorological conditions, aging of semi-volatile and intermediate volatile organic compounds, and contributions from background transport, the non-traditional SOA model is capable of closing the gap in SOA mass between measurements and models.

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Seasonal distribution ofAspergillusin the air of an urban area: Mexico City

Grana ◽

10.1080/00173139209429454 ◽

1992 ◽

Vol 31 (4) ◽

pp. 315-319 ◽

Cited By ~ 10

Author(s):

I. Rosas ◽

C. Calderón ◽

B. Escamilla ◽

M. Ulloa

Keyword(s):

Urban Area ◽

Mexico City ◽

Seasonal Distribution

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Changes in Intense Precipitation Events in Mexico City

Journal of Hydrometeorology ◽

10.1175/jhm-d-14-0081.1 ◽

2015 ◽

Vol 16 (4) ◽

pp. 1804-1820 ◽

Cited By ~ 13

Author(s):

Carlos A. Ochoa ◽

Arturo I. Quintanar ◽

Graciela B. Raga ◽

Darrel Baumgardner

Keyword(s):

Land Use ◽

Urban Area ◽

Mexico City ◽

Urban Areas ◽

Wet Season ◽

Mountain Areas ◽

Surface Exchange ◽

Intense Precipitation ◽

Precipitation Decrease ◽

Alternative Hypotheses

Abstract The authors analyzed an extensive precipitation dataset available for the Mexico City basin that included hourly precipitation in various sectors of the city from 1993 to 2007. Observations indicated that significant changes occurred in the timing and number of intense events (precipitation rate >20 mm h−1) over this time period. Alternative hypotheses that changes in the emission of aerosol pollutants or in the land use can result in the observed variations are tested. The Weather Research and Forecasting Model was used to simulate September precipitation from 2002 to 2011 at the peak of the wet season. Changes were introduced to the microphysical scheme as a proxy for differences in the aerosol population and the droplet activation spectra. Simulations were also performed with the land use of the urban areas set up to represent older and more current conditions. Results indicate that increased pollution (decreased urban area) led to an average precipitation decrease over the mountain areas of 20%–40% (10%–20%) and an increase of 20% (30%) to the east of Mexico City. The timing of intense precipitation shifts from 1900 to 1600 LT for the polluted and decreased urban area cases when compared to a control experiment. These results add valuable information about how precipitation is modified by complex terrain and surface exchange processes in large urban areas under wet conditions.

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Detection of Alphacoronavirus in velvety free-tailed bats (Molossus molossus) and Brazilian free-tailed bats (Tadarida brasiliensis) from urban area of Southern Brazil

Virus Genes ◽

10.1007/s11262-013-0899-x ◽

2013 ◽

Vol 47 (1) ◽

pp. 164-167 ◽

Cited By ~ 11

Author(s):

Francisco Esmaile de Sales Lima ◽

Fabrício Souza Campos ◽

Hiran Castagnino Kunert Filho ◽

Helena Beatriz de Carvalho Ruthner Batista ◽

Pedro Carnielli Júnior ◽

...

Keyword(s):

Urban Area ◽

Southern Brazil ◽

Tadarida Brasiliensis ◽

Molossus Molossus

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Variations of PM10 mass concentrations and correlations with other pollutants in Belgrade urban area

Chemical Industry and Chemical Engineering Quarterly ◽

10.2298/ciceq090910041j ◽

2010 ◽

Vol 16 (3) ◽

pp. 251-258 ◽

Cited By ~ 5

Author(s):

Jasminka Joksic ◽

Mirjana Radenkovic ◽

Anka Cvetkovic ◽

Snezana Matic-Besarabic ◽

Milena Jovasevic-Stojanovic ◽

...

Keyword(s):

Urban Area ◽

Sampling Site ◽

Monitoring Network ◽

European Standard ◽

Street Level ◽

Limit Value ◽

Autumn And Winter ◽

Pm10 Mass ◽

Automatic Station ◽

Mass Concentrations

In this paper, we present the PM10 levels measured at an urban residential background site in New Belgrade, in Omladinskih Brigada Street, at 15 m height (roof). The aerosol samples were collected using European standard sampler, in four seasonal campaigns conducted in autumn: Nov 13-Dec 03, 2007, winter: Feb 07-28, 2008, spring: May 06-28, 2008 and summer: July 17- August 15, 2008. The results were compared with PM10 mass concentrations measured with Horiba automatic station at street level, at the same sampling site and at three more sites within Belgrade municipal monitoring network. The results show that PM10 values in Belgrade urban area were high during autumn and winter campaigns (heating season) with a number of samples exceeding the 24-hr limit value of 50 mg m-3. On the roof station, maximum daily value was 209 mg m-3 measured in the autumn campaign, with 14 values out of 20 measurements exceeding the 24hr limit. In winter, 14 out of 19 measurements exceeded the limit, with maximum value 196 mg m-3. During the spring campaign, number of exceedances was three out of 22. All values during summer campaign were below 50 mg m-3. The roof station equipped with the European Standard instrument showed systematically higher values than the street-level automatic monitor. PM10 values at all sites followed the same trend. The highest concentrations at all monitoring sites were observed during the autumn, Nov 20-Nov 25, 2007 and winter, Feb 19-Feb 23, 2008.

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Fast airborne aerosol size and chemistry measurements above Mexico City and Central Mexico during the MILAGRO campaign

Atmospheric Chemistry and Physics ◽

10.5194/acp-8-4027-2008 ◽

2008 ◽

Vol 8 (14) ◽

pp. 4027-4048 ◽

Cited By ~ 336

Author(s):

P. F. DeCarlo ◽

E. J. Dunlea ◽

J. R. Kimmel ◽

A. C. Aiken ◽

D. Sueper ◽

...

Keyword(s):

Urban Area ◽

Mexico City ◽

Atomic Ratio ◽

Central Mexico ◽

Strongly Correlated ◽

Aerosol Mass ◽

Biogenic Voc ◽

Strong Source ◽

The Stability ◽

Photochemical Age

Abstract. The concentration, size, and composition of non-refractory submicron aerosol (NR-PM1) was measured over Mexico City and central Mexico with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) onboard the NSF/NCAR C-130 aircraft as part of the MILAGRO field campaign. This was the first aircraft deployment of the HR-ToF-AMS. During the campaign the instrument performed very well, and provided 12 s data. The aerosol mass from the AMS correlates strongly with other aerosol measurements on board the aircraft. Organic aerosol (OA) species dominate the NR-PM1 mass. OA correlates strongly with CO and HCN indicating that pollution (mostly secondary OA, SOA) and biomass burning (BB) are the main OA sources. The OA to CO ratio indicates a typical value for aged air of around 80 μg m−3 (STP) ppm−1. This is within the range observed in outflow from the Northeastern US, which could be due to a compensating effect between higher BB but lower biogenic VOC emissions during this study. The O/C atomic ratio for OA is calculated from the HR mass spectra and shows a clear increase with photochemical age, as SOA forms rapidly and quickly overwhelms primary urban OA, consistent with Volkamer et al. (2006) and Kleinman et al. (2008). The stability of the OA/CO while O/C increases with photochemical age implies a net loss of carbon from the OA. BB OA is marked by signals at m/z 60 and 73, and also by a signal enhancement at large m/z indicative of larger molecules or more resistance to fragmentation. The main inorganic components show different spatial patterns and size distributions. Sulfate is regional in nature with clear volcanic and petrochemical/power plant sources, while the urban area is not a major regional source for this species. Nitrate is enhanced significantly in the urban area and immediate outflow, and is strongly correlated with CO indicating a strong urban source. The importance of nitrate decreases with distance from the city likely due to evaporation. BB does not appear to be a strong source of nitrate despite its high emissions of nitrogen oxides, presumably due to low ammonia emissions. NR-chloride often correlates with HCN indicating a fire source, although other sources likely contribute as well. This is the first aircraft study of the regional evolution of aerosol chemistry from a tropical megacity.

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Characterization of organic ambient aerosol during MIRAGE 2006 on three platforms

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-5417-2009 ◽

2009 ◽

Vol 9 (15) ◽

pp. 5417-5432 ◽

Cited By ~ 90

Author(s):

S. Gilardoni ◽

S. Liu ◽

S. Takahama ◽

L. M. Russell ◽

J. D. Allan ◽

...

Keyword(s):

Carboxylic Acid ◽

Elemental Composition ◽

Urban Area ◽

Mexico City ◽

Functional Group ◽

Organic Functional Group ◽

The City ◽

Average Contribution ◽

Group Concentration

Abstract. Submicron atmospheric aerosol particles were collected during the Megacity Initiative: Local and Global Research Observation (MILAGRO) in March 2006 at three platforms located in the Mexico City urban area (at the Mexico City Atmospheric Monitoring System building – SIMAT), at about 60 km south-east of the metropolitan area (Altzomoni in the Cortes Pass), and on board the NCAR C130 aircraft. Organic functional group and elemental composition were measured by FTIR and XRF. The average organic mass (OM) concentration, calculated as the sum of organic functional group concentrations, was 9.9 μg m−3 at SIMAT, 6.6 μg m−3 at Altzomoni, and 5.7 μg m−3 on the C130. Aliphatic saturated C-C-H and carboxylic acid COOH groups dominated OM (more than 60%) at the ground sites. On the C130, a non-acid carbonyl C=O, carboxylic acid COOH, and amine NH2 groups were observed in concentrations above detection limit only outside the Mexico City basin. From the elemental composition of SIMAT samples, we estimated the upper bound of average contribution of biomass burning to the organic carbon (OC) as 33–39%. The average OM/OC ratio was 1.8 at SIMAT, 2.0 at Altzomoni, and 1.6–1.8 on the C130. On the aircraft, higher OM/OC ratios were measured outside of the Mexico City basin, north of the urban area, along the city outflow direction. The average carboxylic acid to aliphatic saturated ratio at SIMAT reflected a local increase of oxidized functional group concentration in aged particles.

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Selection of Building Roosts by Mexican Free-Tailed Bats (Tadarida brasiliensis) in an Urban Area

Acta Chiropterologica ◽

10.3161/15081109acc2015.17.2.007 ◽

2015 ◽

Vol 17 (2) ◽

pp. 321-330 ◽

Cited By ~ 4

Author(s):

Han Li ◽

Kenneth T. Wilkins

Keyword(s):

Urban Area ◽

Tadarida Brasiliensis ◽

Selection Of

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Simulations of organic aerosol concentrations in Mexico City using the WRF-CHEM model during the MCMA-2006/MILAGRO campaign

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-29349-2010 ◽

2010 ◽

Vol 10 (12) ◽

pp. 29349-29404 ◽

Cited By ~ 1

Author(s):

G. Li ◽

M. Zavala ◽

W. Lei ◽

A. P. Tsimpidi ◽

V. A. Karydis ◽

...

Keyword(s):

Urban Area ◽

Mexico City ◽

Aging Process ◽

Organic Aerosol ◽

Suburban Area ◽

Traditional Model ◽

Background Site ◽

Organic Components ◽

Early Afternoon ◽

The City

Abstract. Organic aerosol concentrations are simulated using the WRF-CHEM model in Mexico City during the period from 24 to 29 March in association with the MILAGRO-2006 campaign. Two approaches are employed to predict the variation and spatial distribution of the organic aerosol concentrations: (1) a traditional 2-product secondary organic aerosol (SOA) model with non-volatile primary organic aerosols (POA); (2) a non-traditional SOA model including the volatility basis-set modeling method in which primary organic components are assumed to be semi-volatile and photochemically reactive and are distributed in logarithmically spaced volatility bins. The MCMA 2006 official emission inventory is used in simulations and the POA emissions are modified and distributed by volatility based on dilution experiments for the non-traditional SOA model. The model results are compared to the Aerosol Mass Spectrometry (AMS) observations analyzed using the Positive Matrix Factorization (PMF) technique at an urban background site (T0) and a suburban background site (T1) in Mexico City. The traditional SOA model frequently underestimates the observed POA concentrations during rush hours and overestimates the observations in the rest of the time in the city. The model also substantially underestimates the observed SOA concentrations, particularly during daytime, and only produces 21% and 25% of the observed SOA mass in the suburban and urban area, respectively. The non-traditional SOA model performs well in simulating the POA variation, but still overestimates during daytime in the urban area. The SOA simulations are significantly improved in the non-traditional SOA model compared to the traditional SOA model and the SOA production is increased by more than 100% in the city. However, the underestimation during daytime is still salient in the urban area and the non-traditional model also fails to reproduce the high level of SOA concentrations in the suburban area. In the non-traditional SOA model, the aging process of primary organic components considerably decreases the OH levels in simulations and further impacts the SOA formation. If the aging process in the non-traditional model does not have feedback on the OH in the gas-phase chemistry, the SOA production is enhanced by more than 10% compared to the simulations with the OH feedback during daytime, and the gap between the simulations and observations in the urban area is around 3 μg m−3 or 20% on average during late morning and early afternoon, within the uncertainty from the AMS measurements and PMF analysis. In addition, glyoxal and methylglyoxal can contribute up to approximately 10% of the observed SOA mass in the urban area and 4% in the suburban area. Including the non-OH feedback and the contribution of glyoxal and methylglyoxal, the non-traditional SOA model can explain up to 83% of the observed SOA in the urban area, and the underestimation during late morning and early afternoon is reduced to 0.9 μg m−3 or 6% on average. Considering the uncertainties from measurements, emissions, meteorological conditions, aging of SOA from anthropogenic VOCs, and contributions from background transport, the non-traditional SOA model is capable of closing the gap in SOA mass between measurements and models.

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