Vehicle Ammonia Emissions Measured in An Urban Environment in Sydney, Australia, Using Open Path Fourier Transform Infra-Red Spectroscopy

GrassGroTM simulation of pasture, animal performance and greenhouse emissions on low and high sheep productivity grazing systems: 1-year validation and 25-year analysis

Globally, there is a focus on reducing the absolute methane (CH4) and nitrous oxide emissions, and the emissions intensity (EI, kg CO2e/kg animal product) of livestock production. Increasing the productivity of mixed pasture systems has the potential to increase food (e.g., lamb) and textile fibre (e.g., wool) production while reducing the EI of those products from grazing livestock. The objective of this study was to quantify the differences in greenhouse gas (GHG) emissions and EI between sheep on Low (i.e., low sustainable stocking rate) and High (i.e., high sustainable stocking rate) productivity grazing systems (PGSs). Therefore, a replicated breeding-ewe trial on 18 paddocks was established across 2 - years. Three flocks on Low (3 × 16 ewes/flock) and High PGSs (3 × 32 ewes/flock) rotated across three land-classes and three paddocks per PGS. In year 1, the observed on-farm pasture quantity, quality, and botanical composition, together with lamb BW (kg), and daily CH4 production (DMP, g CH4/head per day) using Open Path Fourier Transformed Infrared (OP-FTIR) spectrometers data were measured. Subsequently, two simulations using GrassGroTM were conducted: (1) a 1-year GrassGroTM simulation that used the observed on-farm data to adjust parameters: date of mating, paddock fertility, and weight of mature ewes to validate GrassGroTM predictions to achieve accuracy and precision targets; and (2) a 25-year (1986-2011) simulation to analyse the effects of Low and High PGSs on sheep production and GHG emissions across a variable climate. The 1-year validation predictions fitted well with the observed on-farm data for: pasture biomass (kg/ha), DM digestibility (%), botanical composition (kg/ha), lamb (kg) product, and DMP (g CH4/head per day). The subsequent predicted results from the 25-year GrassGroTM simulation showed minimal effect of PGS on the mean DM intake (kg DM/day) or DMP for Low and High PGSs, but this was thought to be due to the biomass in both PGSs exceeding 1 500 kg DM/ha. The EI, over the 25-year simulation, on the High PGS was 16.5% lower than the Low PGS. Additional calculations of DMP were conducted using a recent global equation, giving estimates of DMP that closely matched the observed on-farm OP-FTIR DMP measurements, but these were lower than the GrassGroTM predictions and improved the accuracy and precision. It is concluded that in some pasture situations, managing pastures and stock numbers to intensify grazing systems can allow increased livestock production, without increasing daily CH4 emissions/head while substantially decreasing the EI of the animal products generated.

Determination of Greenhouse Gas Concentrations from the 16U CubeSat Spacecraft Using Fourier Transform Infrared Spectroscopy

Greenhouse gases absorb the Earth's thermal radiation and partially return it to the Earth's surface. When accumulated in the atmosphere, greenhouse gases lead to an increase in the average global air temperature and, as a result, climate change. In this paper, an approach to measuring CO2 and CH4 concentrations using Fourier transform infrared spectroscopy (FTIR) is proposed. An FTIR spectrometer mockup, operating in the wavelength range from 1.0 to 1.7 μm with a spectral resolution of 10 cm-1, is described. The results of CO2 and CH4 observations throughout a day in urban conditions are presented. A low-resolution FTIR spectrometer for the 16U CubeSat spacecraft is described. The FTIR spectrometer has a 2.0-2.4 μm spectral range for CO2 and CH4 bands, a 0.75-0.80 μm range for reference O2 bands, an input field of view of 10-2 rad and a spectral resolution of 2 cm-1. The capabilities of the 16U CubeSat spacecraft for remote sensing of greenhouse gas emissions using a developed FTIR spectrometer are discussed. The design of a 16U CubeSat spacecraft equipped with a compact, low-resolution FTIR spectrometer is presented.

Spatial Distributions of Atmospheric Ammonia in a Rural Area in South Korea and the Associated Impact on a Nearby Urban Area

Ammonia (NH3) plays an important role in air quality and atmospheric chemistry, yet studies on the characteristics and impacts of NH3 are limited. Herein, we revealed the spatial distribution of atmospheric NH3, as measured by passive samplers, at three different sites (R1, R2, and R3) in the rural area (livestock environment) of Jeongeup, South Korea, from September 2019 to August 2020. At site R1, the boundary of a large-scale pig farm, dramatically high daily mean concentrations of NH3 were observed (118.7 ppb), whereas sites R2 and R3, located ~1 km from R1, exhibited lower concentrations of 18.2 and 30.4 ppb, respectively. In the rural environment, the monthly NH3 variations showed a peak in June (34.2 ppb), which was significantly higher than in the urban and remote areas. To examine the impact of NH3 from the rural area on a nearby urban area in June 2020, simultaneous measurements were performed using a real-time instrument in Jeonju. When high NH3 events occurred in the urban area in June, the results for the NH3 concentrations and observed meteorological conditions in the rural and urban areas showed that the rural area influenced the NH3 levels in the adjacent urban area.

Fourier Transform Infrared (FTIR) Spectroscopy for Measurements of Vehicle Exhaust Emissions: A Review

Pollution from vehicles is a serious concern for the environment and human health. Vehicle emission regulations worldwide have limits for pollutants such as hydrocarbons, CO, and NOx. The measurements are typically conducted at engine dynamometers (heavy-duty engines) sampling from the tailpipe or at chassis dynamometers (light-duty vehicles) sampling from the dilution tunnel. The latest regulations focused on the actual emissions of the vehicles on the road. Greenhouse gases (GHG) (such as CO2, CH4, N2O), and NH3 have also been the subject of some regulations. One instrument that can measure many gaseous compounds simultaneously is the Fourier transform infrared (FTIR) spectrometer. In this review the studies that assessed FTIRs since the 1980s are summarized. Studies with calibration gases or vehicle exhaust gas in comparison with well-established techniques were included. The main conclusion is that FTIRs, even when used at the tailpipe and not at the dilution tunnel, provide comparable results with other well-established techniques for CO2, CO, NOx, while for hydrocarbons, higher deviations were noticed. The introduction of FTIRs in the regulation needs a careful description of the technical requirements, especially interference tests. Although the limited results of prototype portable FTIRs for on-road measurement are promising, their performance at the wide range of environmental conditions (temperature, pressure, vibrations) needs further studies.

Air Pollution: Sensitive Detection of PM2.5 and PM10 Concentration Using Hyperspectral Imaging

This paper proposes a method to detect air pollution by applying a hyperspectral imaging algorithm for visible light, near infrared, and far infrared. By assigning hyperspectral information to images from monocular, near infrared, and thermal imaging, principal component analysis is performed on hyperspectral images taken at different times to obtain the solar radiation intensity. The Beer–Lambert law and multivariate regression analysis are used to calculate the PM2.5 and PM10 concentrations during the period, which are compared with the corresponding PM2.5 and PM10 concentrations from the Taiwan Environmental Protection Agency to evaluate the accuracy of this method. This study reveals that the accuracy in the visible light band is higher than the near-infrared and far-infrared bands, and it is also the most convenient band for data acquisition. Therefore, in the future, mobile phone cameras will be able to analyze the PM2.5 and PM10 concentrations at any given time using this algorithm by capturing images to increase the convenience and immediacy of detection.

A Clean Air Plan for Sydney: An Overview of the Special Issue on Air Quality in New South Wales

This paper presents a summary of the key findings of the special issue of Atmosphere on Air Quality in New South Wales and discusses the implications of the work for policy makers and individuals. This special edition presents new air quality research in Australia undertaken by (or in association with) the Clean Air and Urban Landscapes hub, which is funded by the National Environmental Science Program on behalf of the Australian Government’s Department of the Environment and Energy. Air pollution in Australian cities is generally low, with typical concentrations of key pollutants at much lower levels than experienced in comparable cities in many other parts of the world. Australian cities do experience occasional exceedances in ozone and PM2.5 (above air pollution guidelines), as well as extreme pollution events, often as a result of bushfires, dust storms, or heatwaves. Even in the absence of extreme events, natural emissions play a significant role in influencing the Australian urban environment, due to the remoteness from large regional anthropogenic emission sources. By studying air quality in Australia, we can gain a greater understanding of the underlying atmospheric chemistry and health risks in less polluted atmospheric environments, and the health benefits of continued reduction in air pollution. These conditions may be representative of future air quality scenarios for parts of the Northern Hemisphere, as legislation and cleaner technologies reduce anthropogenic air pollution in European, American, and Asian cities. However, in many instances, current legislation regarding emissions in Australia is significantly more lax than in other developed countries, making Australia vulnerable to worsening air pollution in association with future population growth. The need to avoid complacency is highlighted by recent epidemiological research, reporting associations between air pollution and adverse health outcomes even at air pollutant concentrations that are lower than Australia’s national air quality standards. Improving air quality is expected to improve health outcomes at any pollution level, with specific benefits projected for reductions in long-term exposure to average PM2.5 concentrations.

Air Quality Impacts of Smoke from Hazard Reduction Burns and Domestic Wood Heating in Western Sydney

Air quality was measured in Auburn, a western suburb of Sydney, Australia, for approximately eighteen months during 2016 and 2017. A long open-path infrared spectrometer sampled path-averaged concentrations of several gaseous species, while other pollutants such as PM 2.5 and PM 10 were sampled by a mobile air quality station. The measurement site was impacted by a number of indoor wood-heating smoke events during cold winter nights as well as some major smoke events from hazard reduction burning in the spring of 2017. In this paper we compare the atmospheric composition during these different smoke pollution events and assess the relative overall impact on air quality from domestic wood-heaters and prescribed forest fires during the campaign. No significant differences in the composition of smoke from these two sources were identified in this study. Despite the hazard reduction burning events causing worse peak pollution levels, we find that the overall exposure to air toxins was greater from domestic wood-heaters due to their higher frequency and total duration. Our results suggest that policy-makers should place a greater focus on reducing wood-smoke pollution in Sydney and on communicating the issue to the public.