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TROPOspheric Monitoring Instrument (TROPOMI), on‐board the Sentinel‐5 Precurser satellite, is a nadir‐viewing spectrometer measuring reflected sunlight in the ultraviolet, visible, near‐infrared, and shortwave infrared. From these spectra several important air quality and climate‐related atmospheric constituents are retrieved, including nitrogen dioxide (NO2) at unprecedented spatial resolution from a satellite platform. We present the first retrievals of TROPOMI NO2over the Canadian Oil Sands, contrasting them with observations from the Ozone Monitoring Instrument satellite instrument, and demonstrate TROPOMI's ability to resolve individual plumes and highlight its potential for deriving emissions from individual mining facilities. Further, the first TROPOMI NO2validation is presented, consisting of aircraft and surface in situ NO2observations, and ground‐based remote‐sensing measurements between March and May 2018. Our comparisons show that the TROPOMI NO2vertical column densities are highly correlated with the aircraft and surface in situ NO2observations, and the ground‐based remote‐sensing measurements with a low bias (15–30 %); this bias can be reduced by improved air mass factors. Nitrogen dioxide (NO2) is a pollutant that is linked to respiratory health issues and has negative environmental impacts such as soil and water acidification. Near the surface the most significant sources of NO2are fossil fuel combustion and biomass burning. With a recently launched satellite instrument (TROPOspheric Monitoring Instrument [TROPOMI]), NO2can be measured with an unprecedented combination of accuracy, spatial coverage, and resolution. This work presents the first TROPOMI NO2measurements near the Canadian Oil Sands and shows that these measurements have an outstanding ability to detect NO2on a very high horizontal resolution that is unprecedented for satellite NO2observations. Further, these satellite measurements are in excellent agreement with aircraft and ground‐based measurements. First evaluation of the TROPOMI NO2retrieval productThe quality of the TROPOMI NO2data is excellent and captures variation on a very high spatial resolutionTROPOMI tropospheric NO2retrievals can be corrected with higher‐resolution input data

Wildfires have become larger and more frequent because of climate change, increasing their impact on air pollution. Air quality forecasts and climate models do not currently account for changes in the composition of wildfire emissions during the commonly observed progression from more flaming to smoldering combustion. Laboratory measurements have consistently shown decreased nitrogen dioxide (NO2) relative to carbon monoxide (CO) over time, as they transitioned from more flaming to smoldering combustion, while formaldehyde (HCHO) relative to CO remained constant. Here, we show how daily ratios between column densities of NO2versus those of CO and HCHO versus CO from the Tropospheric Monitoring Instrument (TROPOMI) changed for large wildfires in the Western United States. TROPOMI‐derived emission ratios were lower than those from the laboratory. We discuss reasons for the discrepancies, including how representative laboratory burns are of wildfires, the effect of aerosols on trace gas retrievals, and atmospheric chemistry in smoke plumes. Climate change has led to an increase in the frequency and size of wildfires in the Western United States. The gases and particles released from wildfires impact air quality and climate, so it is important to understand the chemical composition of these emissions. In current air quality forecasts and climate models, the composition of wildfire emissions is based on the dominant vegetation burned and is assumed to be constant over time. In contrast, measurements from laboratory burns indicate that the composition of emissions from fires changes over time, as fires progress from more flaming combustion to flameless burning dominated by smoke (smoldering). It is challenging to have daily field measurements of the emissions from long‐lived wildfires, but there are instruments in space that can make daily observations of wildfires globally. In this study, we show how the composition of emissions from wildfires in California, Oregon, and Washington changed over time, as they progressed from more flaming to more smoldering combustion, using observations from a satellite instrument called TROPOMI. The analysis of the composition of wildfire emissions and their evolution over time using TROPOMI could improve air quality forecasting and climate modeling globally. Space‐based remote sensing instruments can be used to observe changes in the composition of wildfire emissions over timeChanges in wildfire emissions composition observed with TROPOMI were caused by evolving combustion conditions rather than aerosol shieldingTROPOMI observations can be used to help parametrize how modeled wildfire emissions should change with evolving combustion conditions Space‐based remote sensing instruments can be used to observe changes in the composition of wildfire emissions over time Changes in wildfire emissions composition observed with TROPOMI were caused by evolving combustion conditions rather than aerosol shielding TROPOMI observations can be used to help parametrize how modeled wildfire emissions should change with evolving combustion conditions

We have analyzed Sentinel‐5 Precursor TROPOspheric Monitoring Instrument (TROPOMI) data over the Copperbelt mining region (Democratic Republic of Congo and Zambia). Despite high background values, annual 2019–2022 means of TROPOMI NO2(nitrogen dioxide) show local enhancements consistent with six point sources (four copper/cobalt mines, two cities) where high‐emission industrial activities take place. We have quantified annual NOx(nitrogen oxides) emissions from these point sources, identified temporal trends in emissions, and found strong correlations with production data from colocated mines and one oil refinery. The Copernicus Atmosphere Monitoring Service Global Anthropogenic (CAMS‐GLOB‐ANT) version 5 inventory underpredicts TROPOMI‐derived emissions and lacks the temporal trends observed in TROPOMI and mine/refinery production. These results demonstrate the potential for satellite monitoring of mining and other industrial activities, often unreported or underestimated, which impact the air quality of local communities. This is particularly important for Africa, where mining is increasing aggressively. We show for the first time that annual NOxgas pollution emitted by individual copper/cobalt mines can be measured with TROPOMI satellite data, even in the presence of high background pollution from biomass burning and other sources. This is important for monitoring the air quality of local communities, particularly when these industrial activities proliferate in close proximity to population centers (as is the case in the Copperbelt mining region and in other African regions) and without sufficient ground measurements of air pollution levels. Additionally, we show for the first time that the annual amount of NOxpollution emitted by these single point sources is strongly correlated with annual production from individual, colocated copper/cobalt mines and one oil refinery. Studies like this can be used to estimate mine/oil refinery production before companies release their annual reports or (for non‐publicly traded companies) in the absence of such reports. Insufficient emissions from mines claiming high production could indicate production from a different source. Joint analysis of satellite‐derived emissions and mine production reports could be useful in improving the traceability of minerals extracted in conflict areas. We quantified annual TROPOspheric Monitoring Instrument (TROPOMI)‐derived NOxemissions from point sources corresponding to copper/cobalt mines, despite high background valuesAnnual emissions from individual point sources are strongly correlated with annual production from colocated single mines, one oil refineryTROPOMI is relevant to monitoring air quality and mining/industrial production in remote regions where these activities are growing rapidly We quantified annual TROPOspheric Monitoring Instrument (TROPOMI)‐derived NOxemissions from point sources corresponding to copper/cobalt mines, despite high background values Annual emissions from individual point sources are strongly correlated with annual production from colocated single mines, one oil refinery TROPOMI is relevant to monitoring air quality and mining/industrial production in remote regions where these activities are growing rapidly

COVID‐19 caused a historic collapse in fossil fuel demand, a general decline in economic activity, and hydrocarbon price volatility. This resulted in an unprecedented scenario to evaluate the contribution of the O&G (Oil and Gas) industry NO2(nitrogen dioxide) emissions in the Permian basin (United States), currently the second largest hydrocarbon‐bearing area on Earth. TROPOMI (Tropospheric Monitoring Instrument), on board the Sentinel‐5P satellite, has captured the impact of the oil and gas industry emissions during the COVID‐19 lockdown. A generalized drop (∼30%) of NO2emissions derived using the divergence method in comparison with 2019 was observed following the decline in production and drilling (13% and 68% respectively) during the lockdown. NO2tropospheric columns were less impacted with a smaller decrease (∼4%) across the basins. This study demonstrates that the impact of the COVID‐19 lockdown on NO2emissions was not only present in urban areas but also in vast O&G production regions, which shows the potential of TROPOMI to assess future pollution mitigation strategies for this industry. The COVID‐19 pandemic caused a big impact on the oil and gas industry, not only in production but also in price and demand. This situation was a good opportunity to analyze one of the most common gas emissions of this industry, nitrogen dioxide, in one of the biggest oil and gas production areas, the Permian basin. Using satellite imagery, it was observed a generalized drop in nitrogen dioxide emissions during the lockdown period of the pandemic. This study not only shows that the impact of the COVID‐19 pandemic on nitrogen dioxide emissions was present in other environments apart from the urban for example, the oil and gas production regions, but also the capability to monitor it using satellite imagery. The NO2emissions calculated using TROPOMI data and the divergence method coincide with the downturn of O&G activity in the Permian basinAverage NO2tropospheric column concentrations show a weaker decrease (−4%) in comparison to the significant reductions (∼30%) observed in emissions during the COVID‐19 lockdownWe demonstrate a positive spatial and temporal relationship between oil and gas activity rates and emissions of NO2in the Permian basin The NO2emissions calculated using TROPOMI data and the divergence method coincide with the downturn of O&G activity in the Permian basin Average NO2tropospheric column concentrations show a weaker decrease (−4%) in comparison to the significant reductions (∼30%) observed in emissions during the COVID‐19 lockdown We demonstrate a positive spatial and temporal relationship between oil and gas activity rates and emissions of NO2in the Permian basin

Emissions of methane (CH4) in the Permian basin (USA) have been derived for 2019 and 2020 from satellite observations of the Tropospheric Monitoring Instrument (TROPOMI) using the divergence method, in combination with a data driven method to estimate the background column densities. The resulting CH4emission data, which have been verified using model data with known emissions, have a spatial resolution of approximately 10 km. The CH4emissions show moderate spatial correlation with the locations of oil and gas production and drilling activities in the Permian basin, as well as with emissions of nitrogen oxides (NOx). Analysis of the emission maps and time series indicates that a significant fraction of methane emissions in the Permian basin is from frequent widespread emissions sources, rather than from a few infrequent very large unplanned releases, which is important considering possible CH4emission mitigation strategies. In addition to providing spatially resolved emissions, the divergence method also provides the total emissions of the Permian basin and its main sub‐basins. The total CH4emission of the Permian is estimated as 3.0 ± 0.7 Tg yr−1for 2019, which agrees with other independent estimates based on TROPOMI data. For the Delaware sub‐basin, it is estimated as 1.4 ± 0.3 Tg yr−1for 2019, and for the Midland sub‐basin 1.2 ± 0.3 Tg yr−1. In 2020 the emissions are 9% lower compared to 2019 in the entire Permian basin, and respectively 19% and 27% for the Delaware and Midland sub‐basins. Methane is a strong greenhouse gas that contributes to climate change. To be able to mitigate methane emissions, it is important to know the main sources and to monitor if reduction measures work. In this study, we estimated the emissions from the oil and gas industry using satellite observations in the Permian basin in the USA, a region with thousands of wells. We have derived maps of the emissions in this region with a spatial resolution of 10 km, which show enhanced emissions in the main oil and gas production regions. The results indicate that frequent widespread emissions significantly contribute to the methane emissions in the Permian basin. In addition, we were able to estimate annual emissions from the basin, which correspond well with other studies. Methane emissions from the Permian basin in the USA can be derived from satellite data with a spatial resolution of approximately 10 kmThe derived emissions are spatially moderately correlated with satellite‐derived NOxemissions and oil and gas industry activitiesA significant fraction of methane emissions in the Permian basin is from frequent widespread emissions sources related to the oil and gas industry Methane emissions from the Permian basin in the USA can be derived from satellite data with a spatial resolution of approximately 10 km The derived emissions are spatially moderately correlated with satellite‐derived NOxemissions and oil and gas industry activities A significant fraction of methane emissions in the Permian basin is from frequent widespread emissions sources related to the oil and gas industry

The sorption of (methyl-substituted) pyridines and 2,2-dimethylalkanes on the medium-pore zeolites FER and TON has been studied by in situ IR spectroscopy, calorimetry, and gravimetry in order to describe sorption at the outer surface and the pore mouths of the zeolite crystals. Six percent and 3% of the Brønsted acid sites (determined by adsorption of 2,4,6-trimethylpyridine) were found to be on the outer surface and the pore mouth of TON and FER, respectively. This result agrees fairly well with the fraction of sites that are available for the 2,2-dimethylalkanes, which are unable to fully enter the pores of the zeolites studied. Remarkably, at low coverage, all three dimethylalkanes adsorb in parallel to the outer surface. As the coverage increases, additional 2,2-dimethylpentane and 2,2-dimethylhexane molecules sorb in such a manner that the propyl and butyl groups point into the pore. Also, approximately 80% of the 2,2-dimethylpentane and 2,2-dimethylhexane molecules that initially sorbed parallel to the outer surface rearrange to this sorption structure. This ordering is well documented by the marked increase in the heat of adsorption as the equilibrium pressure increases and by the IR spectra of hydroxyl groups in interaction with the alkane during this process.

We present a new divergence method to estimated methane (CH4) emissions from satellite observed mean mixing ratio of methane (XCH4) by deriving the regional enhancement of XCH4in the Planetary Boundary Layer (PBL). The applicability is proven by comparing the estimated emissions with its known emission inventory from a 3‐month GEOS‐Chem simulation. When applied to TROPOspheric Monitoring Instrument observations, sources from well‐known oil/gas production areas, livestock farms and wetlands in Texas become clearly visible in the emission maps. The calculated yearly averaged total CH4emission over the Permian Basin is 3.06 (2.82, 3.78) Tg a−1for 2019, which is consistent with previous studies and double that of EDGAR v4.3.2 for 2012. Sensitivity tests on PBL heights, on the derived regional background and on wind speeds suggest our divergence method is quite robust. It is also a fast and simple method to estimate the CH4emissions globally. Methane (CH4) is an important greenhouse gas in the atmosphere and plays a crucial role in the global climate change. It kept increasing over the last decades. About 70% of CH4comes from human activities like oil/gas productions or livestock farms. The recently launched TROPOspheric Monitoring Instrument provides an opportunity to estimate the emissions of CH4on a regional scale. This work presents a new method to fastly derive CH4emissions at a fairly high spatial resolution without a priori knowledge of sources. A new divergence method is developed to estimate methane emissions based on satellite observations, requiring no a priori emissionsThe applicability of this method in identifying and quantifying sources is proven by a GEOS‐Chem simulation with known emission inventoryThe estimated emissions over Texas (United States) based on TROPOspheric Monitoring Instrument observations are evaluated and are found to be robust A new divergence method is developed to estimate methane emissions based on satellite observations, requiring no a priori emissions The applicability of this method in identifying and quantifying sources is proven by a GEOS‐Chem simulation with known emission inventory The estimated emissions over Texas (United States) based on TROPOspheric Monitoring Instrument observations are evaluated and are found to be robust