Inter-seasonal and spatial distribution of ground-level greenhouse gases (CO2, CH4, N2O) over Nagpur in India and their management roadmap

Atmospheric Methane Concentration Allows Estimating Natural Gas Leaks in Heating Systems in Tandil, Argentina

Residential use of natural gas (NG) for heating and cooking purposes may contribute significantly to CH emissions to the atmosphere. To analyze whether the NG demand in the city of Tandil, Argentina, contributes to the increase in atmospheric CH concentration, we conducted systematic collections of time-integrated air samples for a year in six city sites with different population and built-up density. Some meteorological parameters and NG consumption were registered. Atmospheric CH concentration ranged from 1.12 to 1.95 mg m (1.72 to 2.84 ppm) with significant seasonal and spatial variations. In all the sites, with the exception of a peri-urban site bordering rural areas, the maximum CH concentrations were measured during the coldest months, with a statistically significant correlation between residential and commercial NG consumption with respect to air temperature ( < 0.001, = -0.84 to -0.69) and atmospheric CH concentration ( < 0.05, = 0.58 to 0.94). In Argentina, the most popular home heating system is the balanced-draft heater, which has a thermal efficiency of 39 to 63%. This low efficiency allows us to attribute the highest atmospheric CH concentration found during the coldest months mainly to the leaks of the heating systems and the greater residential use of NG. Repairing the gas leaks by increasing thermal efficiency or replacing heating systems with more efficient ones will bring economic, environmental, and health benefits. This study is important for our country where the dependence on the use of NG from heating systems is significant.

Distribution of greenhouse gases in hyper-arid and arid areas of northern Chile and the contribution of the high altitude wetland microbiome (Salar de Huasco, Chile)

Northern Chile harbors different bioclimatic zones including hyper-arid and arid ecosystems and hotspots of microbial life, such as high altitude wetlands, which may contribute differentially to greenhouse gases (GHG) such as carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O). In this study, we explored ground level GHG distribution and the potential role of a wetland situated at 3800 m.a.s.l, and characterized by high solar radiation < 1600 W m^-2, extreme temperature ranges (-12 to 24 °C) and wind stress (< 17 m s^-1). The water source of the wetland is mainly groundwater springs, which generates streams and ponds surrounded by peatlands. These sites support a rich microbial aquatic life including diverse bacteria and archaea communities, which transiently form more complex structures, such as microbial mats. In this study, GHG were measured in the water and above ground level air at the wetland site and along an elevation gradient in different bioclimatic areas from arid to hyper-arid zones. The microbiome from the water and sediments was described by high-throughput sequencing 16S rRNA and rDNA genes. The results indicate that GHG at ground level were variable along the elevation gradient potentially associated with different bioclimatic zones, reaching high values at the high Andean steppe and variable but lower values in the Atacama Desert and at the wetland. The water areas of the wetland presented high concentrations of CH₄ and CO₂, particularly at the spring areas and in air bubbles below microbial mats. The microbial community was rich (> 40 phyla), including archaea and bacteria potentially active in the different matrices studied (water, sediments and mats). Functional microbial groups associated with GHG recycling were detected at low frequency, i.e., < 2.5% of total sequences. Our results indicate that hyper-arid and arid areas of northern Chile are sites of GHG exchange associated with various bioclimatic zones and particularly in aquatic areas of the wetland where this ecosystem could represent a net sink of N₂O and a source for CH₄ and CO₂.