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

Abstract

Residential use of natural gas (NG) for heating and cooking purposes may contribute significantly to CH4 emissions to the atmosphere. To analyze whether the NG demand in the city of Tandil, Argentina, contributes to the increase in atmospheric CH4 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 CH4 concentration ranged from 1.12 to 1.95 mg m−3 (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 CH4 concentrations were measured during the coldest months, with a statistically significant correlation between residential and commercial NG consumption with respect to air temperature (p < 0.001, R = −0.84 to −0.69) and atmospheric CH4 concentration (p < 0.05, R = 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 CH4 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. Core Ideas We studied atmospheric CH4 concentration in an urban area at a southern mid‐latitude. We observed spatial and seasonal variations in atmospheric CH4 concentration. The highest atmospheric CH4 concentrations were measured during the coldest months. Methane concentration and residential natural gas consumption were well correlated. Low‐efficiency heating systems cause an increase in CH4 concentrations.

Analysis of the Influence of Sources on the Spatial Variation in Atmospheric Methane Concentrations in the City of Tandil, Argentina

“…During a study period of one year (June 1st, 2017 -May 31st, 2018), integrated air samples were obtained in consecutive 15-day periods. The samples were collected in 0.5 liter stainless steel canisters with an inlet valve (Fusé et al 2019) and an air ow controller calibrated for the desired sampling period (Gere and Gratton 2010). The canisters were previously cleaned with high purity nitrogen and evacuated to approximately 0.5 mb pressure.…”

“…The canisters were previously cleaned with high purity nitrogen and evacuated to approximately 0.5 mb pressure. At the end of each sampling period, the canisters were replaced and transferred to the laboratory, where samples were analyzed for CH 4 concentration by gas chromatography (CG Agilent 7890A) (Fusé et al 2019). Regarding measurement error, the chromatograph ranges from 1% to 3% (0.02 to 0.05 ppm for ambient air).…”

“…) Fusé et al (2019). suggested that the maximum concentrations of atmospheric CH 4 recorded in the fall and winter in Tandil can be explained by the higher consumption of NG for heating and by gas leaks in the heating systems.…”

“…The development and application of models that allow quantifying the interrelationships between environmental and socioeconomic factors associated with urban growth will help us to learn about the possible future effects of their evolution, key to preventing associated problems(Linares 2019). Although there are overall trends in urban CH 4 emissions, differences exist between cities (geophysical factors-climate, access to resources-and technical factors, such as power generation, urban design, waste processing), which need to be explored by further local research (Kennedy et al2009).In Argentina, some authors have conducted studies on GHG emissions in speci c urban sectors: waste (Sanci and Panarello 2016), NG residential use(Fusé et al 2019), and transport (Pulia to et al 2015). In general, the GHG inventories that Argentina submits to the United Nations Framework Convention on Climate Change (UNFCCC) secretariat, following IPCC guidelines, are based on data and emission factors that do not apply to this region (Secretariat of the Environment and Sustainable Development 2015).…”

“…4 concentrations between seasons (± standard deviation, n = total number of measurements performed in each site, superscript letters show results for Fisher's LSD Test) and results of Pearson correlation analysis (linear correlation coe cients R and signi cance level p in parentheses) between the atmospheric CH 4 concentrations and the mean air temperature (T) at each siteFusé et al (2019) suggested that the maximum concentrations of atmospheric CH 4 recorded in the fall and winter in Tandil can be explained by the higher consumption of NG for heating and by gas leaks in the heating systems. In general, good statistically signi cant correlations were obtained between atmospheric CH…”