Abstract
A new sampling method using polypropylene syringes and chemical analysis by gas chromatography was proposed and applied to determine CO2, CH4 and N2O. The samples' stability was evaluated and compared with the stability of the samples in stainless steel canisters and Tedlar® bags. This methodology was applied to a case study in the urban area of the city of Rio de Janeiro, Brazil. In 2012, annual averages of 507.6 ± 13.2 µmol mol-1 for CO2, 1.95 ± 0.06 µmol mol-1 for CH4 and 325.3 ± 3.4 nmol mol-1 for N2O were obtained. The results for CO2 and CH4 showed peak values in the warmer months and lower values in winter. This CO2 behavior is the opposite of that observed in studies performed in many other cities around the world and may be climate-related. CH4 and N2O inputs are probably due to the evaporation of liquid and solid waste both from landfill sites located within the city boundaries and from polluted rivers and canals. Additionally, other anthropogenic sources may be considered, such as the release of CH4 by the gas fuel network of the urban area and the emissions due to the use of compressed natural gas by light vehicles.
Highlights
According to the National Oceanic and Atmospheric Administration (NOAA), the highest globally averaged temperature for land and ocean surfaces since records began in 1880 was measured in 2014.1 in 2014, for the first time since carbon dioxide has been measured at Mauna Loa Observatory, Hawaii, its peak levels surpassed 400 μmol mol-1 during three consecutive months in the atmosphere.[2]The highest carbon dioxide global average concentration was 398.83 μmol mol-1 in May 2014, according to NOAA.[2]
Carbon dioxide (CO2) is the most important anthropogenic greenhouse gas in the atmosphere;[3] two other gases, i.e., methane (CH4) and nitrous oxide (N2O), are important, and they are all closely related to anthropogenic activities, such as fossil fuel combustion, agriculture, biomass burning and waste management
These results show that the stability of greenhouse gases (GHG) samples is similar in the syringes to that found in the more usual sampling devices
Summary
According to the National Oceanic and Atmospheric Administration (NOAA), the highest globally averaged temperature for land and ocean surfaces since records began in 1880 was measured in 2014.1 in 2014, for the first time since carbon dioxide has been measured at Mauna Loa Observatory, Hawaii, its peak levels surpassed 400 μmol mol-1 during three consecutive months in the atmosphere.[2]The highest carbon dioxide global average concentration was 398.83 μmol mol-1 in May 2014, according to NOAA.[2]. To check the evolution of the hourly concentrations, 12 samples were collected during the period from 6:00 a.m. to 6:00 p.m. on January 3, 2012, at the Maracanã Campus of the Rio de Janeiro State University, where an automatic air quality monitoring station was located.
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