Levels of BTEX (benzene, toluene, ethylbenzene, and p-xylene) were determined in ambient air of an urban site located at the center of Mexico (Leon City in Guanajuato State) during two climatic seasons of 2018 (summer and autumn). Ethylbenzene (11.86 µg m⁻³) and toluene (11.85 µg m⁻³) showed the highest median concentrations during the study period. BTEX concentrations did not show a diurnal pattern but a seasonal trend was observed for benzene and toluene at a significant level of α = 0.05. Bi-variate and multivariate analysis showed significant positive correlations (at α = 0.05) among BTEX (excepting benzene), indicating common sources for toluene, ethylbenzene, and p-xylene and a different origin for benzene. A meteorological study was also conducted in order to determine the origin of air masses that could influence the BTEX concentrations in the study site. Finally, it was found that all BTEX species presented hazard quotient values (HQs) <1, indicating that there is no risk of non-cancer during the studied period. Lifetime cancer risk due to benzene exposure for the adult and child populations studied were estimated to be 7 in 1,000,000 and 1 in 100,000, respectively.

Gust factors in Milwaukee, Wisconsin, are investigated using Automated Surface Observing System (ASOS) wind measurements from 2007 to 2014. Wind and gust observations reported in the standard hourly ASOS dataset are shown to contain substantial bias caused by sampling and reporting protocols that restrict the reporting of gusts to arbitrarily defined “gusty” periods occurring during small subsets of each hour. The hourly ASOS gust reports are found to be inadequate for describing the gust characteristics of the site and ill suited for the study of gust factors. A gust-factor climatology was established for Milwaukee using the higher-resolution, 1-min version of the ASOS dataset. The mean gust factor is 1.74. Stratified climatologies demonstrate that Milwaukee gust factors vary substantially with meteorological factors, with wind speed and wind direction exerting the strongest controls. A variety of modified gust-factor models were evaluated in which the peak wind gust is estimated by multiplying a gust factor by the observed, rather than forecast, wind speed. Errors thus obtained are entirely attributable to utility of the gust factor in forecasting peak gusts, having eliminated any error associated with the wind speed forecast. Results show that gust-factor models demonstrate skill in estimating peak gusts and improve with the use of meteorologically stratified gust factors.

The port of Veracruz is one of the most important ports in Mexico and is currently in the process of a major expansion. The new port area, “Bahía Norte”, will be three times larger than the current port, “Bahía Sur”. Atmospheric emissions from the Veracruz port system, specifically from the engines of ships undergoing maneuvering and hotelling operations, were determined on a daily basis from 2018 to 2019 for sulfur dioxide (SO₂), nitrogen oxides (NO_x), carbon monoxide (CO), non-methane volatile organic compounds (NMVOC), particles (PM), particles smaller than 10 micrometers (PM₁₀), particles smaller than 2.5 micrometers (PM_2.5) and carbon dioxide (CO₂). A bottom-up method was used to estimate the atmospheric emissions, based on official data from the European Environment Agency. The method utilizes on technical information on the type of ship, the power of the main engine (ME) and auxiliary engine (AE), load factor, specific fuel consumption, and spent time in the maneuvering and hotelling phases. The highest atmospheric emissions occurred in the hotelling phase. For the “Bahía Sur” emissions (Mg/year) were 328.6, 993.3, 122.3, 30.6, 22.9, 19.1, 18.5 and 52,723.4 for SO₂, NO_x, CO, NMVOC, PM, PM₁₀, PM_2.5 and CO₂, respectively. For “Bahía Norte” the corresponding emissions were 43.9, 132.7, 16.3, 4.1, 3.1, 2.5, 2.3 and 7,040.9, also in the hotelling phase. The average combined of the atmospheric emissions from maneuvering and hotelling phases (Mg/year) were 1.18, 3.49, 0.44, 0.13, 0.09, 0.08, 0.07, and 189.23 for SO₂, NO_x, CO, NMVOC, PM, PM₁₀, PM_2.5 and CO₂, respectively. During the 2018-2019 period of the study the “Bahía Sur” contributed ~87% and the “Bahía Norte” ~13% of the atmospheric emissions.

A field study was carried out in the Metropolitan Area of Monterrey (MAM), the second most populated city in Mexico, characterized by increasing urbanizati

Atmospheric emissions from vessels at 38 Pacific and Gulf-Caribbean Mexican ports were determined for nitrogen oxides, sulfur dioxide, particulates, carbon monoxide, non-methane volatile organic compounds, and carbon dioxide. The emissions have been estimated using a bottom-up methodology in the maneuver and hoteling phases, by vessel type, from 2005 to 2020. Maritime traffic in Mexico’s Pacific zone contributes approximately with 60% of the country’s total ship emissions, with the remaining 40% in Gulf-Caribbean ports. The highest atmospheric emissions were found at the Manzanillo and Lázaro Cárdenas ports on the Pacific coast, as well as the Altamira and Veracruz ports on the Gulf-Caribbean coast. The contribution of the atmospheric emissions by vessel type at Pacific ports was Container 67%, Bulk Carrier 32%, Tanker 0.8%, and RoRo 0.4%. For Gulf-Caribbean ports it was Container 76%, Bulk Carrier 19%, Tanker 3%, and RoRo 2%. This study incorporates the International Maritime Organization implementations on reductions of sulfur content in marine fuel, from 4.5% mass by mass from 2005 to 2011, to 3.5% from 2012 to 2019, to 0.5% beginning in 2020. Overall, sulfur dioxide emissions were reduced by 89%.