Laser spectrometer for high-resolution measurements of air quality and greenhouse gases

分子氮（N2）向“固定”氮的转化，如氨（NH3）、氮氧化物（NOx = NO + NO2）和氧化亚氮（N2O），在现代由于工业肥料生产和高温燃烧的意外后果而急剧加速。N2O是一种重要的温室气体，对平流层臭氧消耗有重要贡献。在过去四十年中，其大气混合比以每年0.75 ppb的速度持续增加，但对其来源（海洋、自然和管理的土壤、牲畜、生物质燃烧、工业）和汇（平流层中的光解作用）的准确计算仍然缺乏。为了支持研究计划中的各种项目，迫切需要能够进行高时间分辨率和高精度N2O测量的激光光谱仪。选择可以同时测量CO和CO2的光谱仪可以最大限度地提高仪器的适用性，特别是在现场测量的情况下。该仪器将成为实验室研究中使用的成套设备的关键部分，用于测量通过oh引发的NH3氧化产生的NOx和N2O的相对产量。在室内实验中，它还将用于量化土壤样品中N2O（以及NH3和NOx）的排放量，作为温度、湿度、N含量和微生物活动的函数。以高时间分辨率同时测量CO和CO2的能力将用于评估道路交通中特定车辆的CO/CO2排放比。该仪器将有助于在大多伦多地区建立温室气体和空气质量污染物的现场和柱式测量网络，目的是为城市排放清单提供观测限制。作为加拿大大气激光吸收光谱实验试验台（CALASET）项目的一部分，正在开发一种开放路径光谱仪，用于基于气球的大气成分测量。通过与本提案中要求的光谱仪的并排测量结果进行比较，目前正在建设中的这种新型仪器的表征和优化将得到显着改善。

The conversion of molecular nitrogen (N2) to ‘fixed’ nitrogen, e.g. ammonia (NH3), nitrogen oxides (NOx = NO + NO2), and nitrous oxide (N2O), has accelerated dramatically in the modern age due to industrial fertilizer production, and as an unintended consequence of high-temperature combustion. N2O is an important greenhouse gas and contributes significantly to stratospheric ozone depletion. Its atmospheric mixing ratio has been consistently increasing at a rate of 0.75 ppb per year over the last four decades, but an accurate accounting of its sources (ocean, natural and managed soils, livestock, biomass burning, industry) and sinks (photodissociation in the stratosphere) is still lacking. A laser spectrometer capable of high time resolution and high precision N2O measurements is urgently needed to support various projects within the research program. The choice of a spectrometer that can simultaneously measure CO and CO2 maximizes the applicability of the instrument, especially in the context of field measurements. The instrument will be a critical part of the suite of equipment used in laboratory studies to measure the relative yields of NOx and N2O produced through the OH-initiated oxidation of NH3. It will also be used to quantify the emissions of N2O (along with NH3 and NOx) from soil samples as a function of temperature, humidity, N content and microbial activity in chamber experiments. The capability to measure CO and CO2 simultaneously at high time resolution will be used to evaluate vehicle-specific CO/CO2 emission ratios from onroad traffic. The instrument will contribute to a network of in situ and column measurements of greenhouse gases and air quality pollutants in the Greater Toronto Area aimed at providing observational constraints at urban emission inventories. As part of the Canadian Atmospheric Laser Absorption Spectroscopy Experiment Test-bed (CALASET) project, an open-path spectrometer is being developed for balloon-based measurements of atmospheric composition. The characterization and optimization of this novel instrument, currently under construction, will be significantly improved by comparisons with side-by-side measurements from the spectrometer requested in this proposal.