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18 pages, 4788 KiB

Open AccessArticle

Estimation of the Impact of Ozone on Four Economically Important Crops in the City Belt of Central Mexico

by Luis Gerardo Ruiz-Suárez, Bertha Eugenia Mar-Morales, José Agustín García-Reynoso, Gema Luz Andraca-Ayala, Ricardo Torres-Jardón, José Santos García-Yee, Hugo Alberto Barrera-Huertas, Arturo Gavilán-García and Roberto Basaldud Cruz

Atmosphere 2018, 9(6), 223; https://doi.org/10.3390/atmos9060223 - 11 Jun 2018

Cited by 5 | Viewed by 4740

Abstract

In this work, we report the economic impact of exposure to high ozone concentrations on four important crops in the area of influence of the Mexico City Megalopolis. Estimated yield losses were as follows: maize: 3%; oats: 26%; beans: 14%; sorghum: 15%. The [...] Read more.

In this work, we report the economic impact of exposure to high ozone concentrations on four important crops in the area of influence of the Mexico City Megalopolis. Estimated yield losses were as follows: maize: 3%; oats: 26%; beans: 14%; sorghum: 15%. The information needed to estimate the impact of air pollution in Mexico is decidedly deficient. Regarding ozone, the coverage provided by the monitoring networks is strongly focused on urban monitoring and its consistency over time is highly irregular. Apart from the Mexico City Metropolitan Area (MCMA) and less than a handful of other cities, the quality of the data is poor. Ozone in rural areas can be estimated with air quality models. However, these models depend on a high-resolution emissions inventory, which has only been done through validation processes in the MCMA. With these limitations, we set out to estimate the economic impact of exposure to ozone in these crops with a varying degree of sensitivity to ozone in the city belt of Central Mexico. To this end, we developed a procedure that makes optimal use of the sparse information available for construction of AOT40 (accumulated exposure over the threshold of 40 ppb) exceedance maps for the 2011 growing season. We believe that, due to the way in which we dealt with the sparse information and the uncertainty regarding the available data, our findings lie on the safe side of having little knowledge such that they may be useful to decision-makers. We believe that this procedure can be extended to the rest of the country, and that it may be useful to developing countries with similar monitoring and modeling capacities. In addition, these impacts are not evenly distributed in the region and sometimes they were greater in municipalities that have a higher index of poverty. Air pollution arriving from urban areas increases the social inequalities to which these already vulnerable populations are exposed. Full article

(This article belongs to the Special Issue Tropospheric Ozone and Its Precursors)

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12538 KiB

Open AccessArticle

The Variability of Ozone Sensitivity to Anthropogenic Emissions with Biogenic Emissions Modeled by MEGAN and BEIS3

by Eunhye Kim, Byeong-Uk Kim, Hyun Cheol Kim and Soontae Kim

Atmosphere 2017, 8(10), 187; https://doi.org/10.3390/atmos8100187 - 23 Sep 2017

Cited by 13 | Viewed by 5206

Abstract

In this study, we examined how modeled ozone concentrations respond to changes in anthropogenic emissions when different modeled emissions of biogenic volatile organic compounds (BVOCs) are used. With biogenic emissions estimated by the Model of Emissions of Gases and Aerosols from Nature (MEGAN) [...] Read more.

In this study, we examined how modeled ozone concentrations respond to changes in anthropogenic emissions when different modeled emissions of biogenic volatile organic compounds (BVOCs) are used. With biogenic emissions estimated by the Model of Emissions of Gases and Aerosols from Nature (MEGAN) and the Biogenic Emissions Inventory System Version 3 (BEIS3), the Community Multi-scale Air Quality with the High-order Direct Decouple Method (CMAQ-HDDM) simulations were conducted to acquire sensitivity coefficients. For the case study, we chose 17–26 August 2007, when the Southern Korean peninsula experienced region-wide ozone standard exceedances. The results show that modeled local sensitivities of ozone to anthropogenic emissions in certain NO_x-saturated places can differ significantly depending on the method used to estimate BVOC emission, with an opposite trend of ozone changes alongside NO_x reductions often shown in model runs using MEGAN and BEIS3. Findings of increased ozone concentrations with one model and decreased ozone concentrations with the other model implies that estimating BVOCs emissions is an important element in predicting variability in ozone concentration and determining the responses of ozone concentrations to emission changes, a discovery that may lead to different policy decisions related to air quality improvement. Quantitatively, areas in the 3-km modeling domain that experienced daily maximum one-hour ozone concentrations greater than 120 ppb (MDA1O3) showed differences of over 20 ppb in MDA1O3 values between model runs with MEGAN and BEIS3. For selected monitoring sites, the maximum difference in relative daily maximum eight-hour ozone concentrations (MDA8O3) response between the methods to model BVOCs was 4.2 ppb in MDA8O3 when we adopted a method similar to the Relative Reduction Factor used by the US Environmental Protection Agency (EPA). Full article

(This article belongs to the Special Issue Tropospheric Ozone and Its Precursors)

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1315 KiB

Open AccessArticle

Seasonal Trends of Formaldehyde and Acetaldehyde in the Megacity of São Paulo

by Thiago Nogueira, Pamela A. Dominutti, Adalgiza Fornaro and Maria De Fatima Andrade

Atmosphere 2017, 8(8), 144; https://doi.org/10.3390/atmos8080144 - 08 Aug 2017

Cited by 23 | Viewed by 5531

Abstract

The Metropolitan Area of São Paulo (MASP) is the largest megacity in South America, with 21 million inhabitants and more than 8 million vehicles. Those vehicles run on a complex fuel mix, with ethanol accounting for nearly 50% of all fuel sold. That [...] Read more.

The Metropolitan Area of São Paulo (MASP) is the largest megacity in South America, with 21 million inhabitants and more than 8 million vehicles. Those vehicles run on a complex fuel mix, with ethanol accounting for nearly 50% of all fuel sold. That has made the MASP a unique case study to assess the impact of biofuel use on air quality. Currently, the greatest challenge in terms of improving air quality is controlling the formation of secondary pollutants such as ozone, which represents the main air pollution problem in the MASP. We evaluated the temporal trends in the concentrations of ozone, its precursors (formaldehyde, acetaldehyde, and NO₂), CO, and NO, from 2012 to 2016. Formaldehyde and acetaldehyde concentrations were frequently higher in winter than in other seasons, showing the importance of meteorological conditions to the distribution of atmospheric pollutants in the MASP. We found no clear evidence that the recent growth in ethanol consumption in Brazil has affected acetaldehyde concentrations, which are associated with emissions from ethanol combustion. In fact, the formaldehyde/acetaldehyde ratio remained relatively constant over the period studied, despite the change in the fuel consumption profile in the MASP. Full article

(This article belongs to the Special Issue Tropospheric Ozone and Its Precursors)

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1311 KiB

Open AccessArticle

Observed and Model-Derived Ozone Production Efficiency over Urban and Rural New York State

by Matthew Ninneman, Sarah Lu, Pius Lee, Jeffery McQueen, Jianping Huang, Kenneth Demerjian and James Schwab

Atmosphere 2017, 8(7), 126; https://doi.org/10.3390/atmos8070126 - 18 Jul 2017

Cited by 14 | Viewed by 5174

Abstract

This study examined the model-derived and observed ozone production efficiency (OPE = ∆O_x/∆NO_z) in one rural location, Pinnacle State Park (PSP) in Addison, New York (NY), and one urban location, Queens College (QC) in Flushing, NY, in New York [...] Read more.

This study examined the model-derived and observed ozone production efficiency (OPE = ∆O_x/∆NO_z) in one rural location, Pinnacle State Park (PSP) in Addison, New York (NY), and one urban location, Queens College (QC) in Flushing, NY, in New York State (NYS) during photo-chemically productive hours (11 a.m.–4 p.m. Eastern Standard Time (EST)) in summer 2016. Measurement data and model predictions from National Oceanic and Atmospheric Administration National Air Quality Forecast Capability (NOAA NAQFC)—Community Multiscale Air Quality (CMAQ) model versions 4.6 (v4.6) and 5.0.2 (v5.0.2) were used to assess the OPE at both sites. CMAQ-predicted and observed OPEs were often in poor agreement at PSP and in reasonable agreement at QC, with model-predicted and observed OPEs, ranging from approximately 5–11 and 10–13, respectively, at PSP; and 4–7 and 6–8, respectively, at QC. The observed relationship between OPE and oxides of nitrogen (NO_x) was studied at PSP to examine where the OPE downturn may have occurred. Summer 2016 observations at PSP did not reveal a distinct OPE downturn, but they did indicate that the OPE at PSP remained high (10 or greater) regardless of the [NO_x] level. The observed OPEs at QC were found by using species-specific reactive odd nitrogen (NO_y) instruments and an estimated value for nitrogen dioxide (NO₂), since observed OPEs determined using non-specific NO_x and NO_y instruments yielded observed OPE results that (1) varied from approximately 11–25, (2) sometimes had negative [NO_z] concentrations, and (3) were inconsistent with CMAQ-predicted OPE. This difference in observed OPEs at QC depending on the suite of instruments used suggests that species-specific NO_x and NO_y instruments may be needed to obtain reliable urban OPEs. Full article

(This article belongs to the Special Issue Tropospheric Ozone and Its Precursors)

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4290 KiB

Open AccessArticle

Characterization and Sources of Aromatic Hydrocarbons (BTEX) in the Atmosphere of Two Urban Sites Located in Yucatan Peninsula in Mexico

by Julia Griselda Cerón Bretón, Rosa María Cerón Bretón, Francisco Vivas Ucan, Cynthia Barceló Baeza, María de la Luz Espinosa Fuentes, Evangelina Ramírez Lara, Marcela Rangel Marrón, Jorge Alfredo Montero Pacheco, Abril Rodríguez Guzmán and Martha Patricia Uc Chi

Atmosphere 2017, 8(6), 107; https://doi.org/10.3390/atmos8060107 - 17 Jun 2017

Cited by 31 | Viewed by 6340

Abstract

Benzene, toluene, ethylbenzene, p-xylene, O₃, NO_x, CO, PM_2.5 and meteorological parameters were measured in urban air of two sites in Merida, Yucatan, Mexico during 2016–2017. Samples were collected using 1.5 h time intervals at three different sampling periods [...] Read more.

Benzene, toluene, ethylbenzene, p-xylene, O₃, NO_x, CO, PM_2.5 and meteorological parameters were measured in urban air of two sites in Merida, Yucatan, Mexico during 2016–2017. Samples were collected using 1.5 h time intervals at three different sampling periods before being analyzed by gas chromatography with flame ionization detection. The highest concentrations of BTEX occurred during midday and afternoon in spring and summer seasons. Mean concentrations of, BTEX for the Cholul and SEDUMA sites, respectively, were 40.91 μg/m³ and 32.86 μg/m³ for benzene; 6.87 μg/m³ and 3.29 μg/m³ for toluene; 13.87 μg/m³ and 8.29 μg/m³ for p-xylene; and 6.23 μg/m³ and 4.48 μg/m³ for ethylbenzene. The toluene/benzene and xylene/ethylbenzene concentration ratios indicated that BTEX levels at both sites were influenced by local and fresh emissions (vehicular traffic). Bivariate and multivariate analyses were performed in order to correlate BTEX concentrations with criteria air pollutants to infer their possible sources. Health risk assessment revealed that exposure to benzene exceeded the recommended value for the integrated lifetime cancer risk. These results suggest that Merida’s population is exposed to cancer risk, and changes in the existing environmental policies should therefore be applied to improve air quality. Full article

(This article belongs to the Special Issue Tropospheric Ozone and Its Precursors)

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1617 KiB

Open AccessArticle

Decomposition Kinetics of Non-Volatile Alkanes on Urban Aerosol

by Dimitra Karali, Spyridon Rapsomanikis and Achilleas Christoforidis

Atmosphere 2017, 8(5), 89; https://doi.org/10.3390/atmos8050089 - 19 May 2017

Cited by 2 | Viewed by 3944

Abstract

The decomposition kinetics of non-volatile n-alkanes that were collected in an urban environment were studied. The quartz filters that they were collected on were exposed in two reactors, in dark and natural light conditions, for four days. Ambient air that was passed through [...] Read more.

The decomposition kinetics of non-volatile n-alkanes that were collected in an urban environment were studied. The quartz filters that they were collected on were exposed in two reactors, in dark and natural light conditions, for four days. Ambient air that was passed through the reactors continuously, ensured a supply of exogenic oxidants to the surface of the filters. The lifetimes of the non-volatile n-alkanes were experimentally determined to be in the order of 3–6 days. The results from the light reactor exhibited approximately a 10% decrease in their lifetime. The results obtained for the prevailing atmospheric conditions and for the duration of the experiments, were in agreement with values from the literature. Full article

(This article belongs to the Special Issue Tropospheric Ozone and Its Precursors)

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4349 KiB

Open AccessArticle

Use of Combined Observational- and Model-Derived Photochemical Indicators to Assess the O₃-NOx-VOC System Sensitivity in Urban Areas

by Edson R. Carrillo-Torres, Iván Y. Hernández-Paniagua and Alberto Mendoza

Atmosphere 2017, 8(2), 22; https://doi.org/10.3390/atmos8020022 - 26 Jan 2017

Cited by 27 | Viewed by 5387

Abstract

Tropospheric levels of O₃ have historically exceeded the official annual Mexican standards within the Monterrey Metropolitan Area (MMA) in NE Mexico. High-frequency and high-precision measurements of tropospheric O₃, NO_y, NO₂, NO, CO, SO₂, PM [...] Read more.

Tropospheric levels of O₃ have historically exceeded the official annual Mexican standards within the Monterrey Metropolitan Area (MMA) in NE Mexico. High-frequency and high-precision measurements of tropospheric O₃, NO_y, NO₂, NO, CO, SO₂, PM₁₀ and PM_2.5 were made at the Obispado monitoring site near the downtown MMA from September 2012 to August 2013. The seasonal cycles of O₃ and NO_y are driven by changes in meteorology and to a lesser extent by variations in primary emissions. The NO_y levels were positively correlated with O₃ precursors and inversely correlated with O₃ and wind speed. Recorded data were used to assess the O₃-Volatile Organic Compounds (VOC)-NO_x system’s sensitivity through an observational-based approach. The photochemical indicator O₃/NO_y was derived from measured data during the enhanced O₃ production period (12:00–18:00 Central Daylight Time (CDT), GMT-0500). The O₃/NO_y ratios calculated for this time period showed that the O₃ production within the MMA is VOC sensitive. A box model simulation of production rates of HNO₃ (P_HNO₃) and total peroxides (P_perox) carried out for O₃ episodes in fall and spring confirmed the VOC sensitivity within the MMA environment. No significant differences were observed in O₃/NO_y from weekdays to weekends or for P_HNO₃/P_perox ratios, confirming the limiting role of VOCs in O₃ production within the MMA. The ratified photochemical regime observed may allow the environmental authorities to revise and verify the current policies for air quality control within the MMA. Full article

(This article belongs to the Special Issue Tropospheric Ozone and Its Precursors)

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Review

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4394 KiB

Open AccessReview

Tropospheric Ozone at Northern Mid-Latitudes: Modeled and Measured Long-Term Changes

by Johannes Staehelin, Fiona Tummon, Laura Revell, Andrea Stenke and Thomas Peter

Atmosphere 2017, 8(9), 163; https://doi.org/10.3390/atmos8090163 - 29 Aug 2017

Cited by 16 | Viewed by 5845

Abstract

In this paper, we investigate why current state-of-the-art chemistry-climate models underestimate the tropospheric ozone increase from the 1950s to the 1990s by approximately 50%. The accuracy of these models is vital, not only for understanding and predicting air quality globally, but also since [...] Read more.

In this paper, we investigate why current state-of-the-art chemistry-climate models underestimate the tropospheric ozone increase from the 1950s to the 1990s by approximately 50%. The accuracy of these models is vital, not only for understanding and predicting air quality globally, but also since they are used to quantify the contribution of ozone in the troposphere and lower stratosphere to climate change, where its greenhouse effect is largest. We briefly describe available northern mid-latitude ozone measurements, which include representative and reliable data from European sites that extend back to the 1950s. We use the SOCOLv3 (Solar Climate Ozone Links version 3) global chemistry-climate model to investigate the individual terms of the tropospheric ozone budget. These include: inflow from the stratosphere, dry deposition, and chemical formation and destruction. For 1960 to 2000 SOCOLv3 indicates a tropospheric ozone increase at 850 hPa over the Swiss Alps (Arosa) of 17 ppb, or around 30%. This increase is smaller than that seen in the surface ozone measurements but similar to other chemistry-climate models, including those with more complex NMVOC (Non Methane Volatile Organic Compound) schemes than SOCOLv3’s. It is likely that the underestimated increase in tropospheric ozone could be explained by issues in the underlying emissions inventories used in the model simulations, with ozone precursor emissions, particularly NO_x (NO + NO₂), from the 1960s being too large. Full article

(This article belongs to the Special Issue Tropospheric Ozone and Its Precursors)

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