Quantifying burning efficiency in Megacities using NO2/CO ratio from the Tropospheric Monitoring Instrument (TROPOMI)

Economic development and rapid urbanization have increased the consumption of fossil fuel in megacities degrading the local air quality. Burning efficiency is a major factor determining the impact of fuel burning on the environment. It varies with environmental conditions and influences the ratio at which pollutants are emitted, as expressed by the emission factor. Emission factors are an important source of uncertainty in global emission inventories.To improve the quantification of burning efficiency and emission factors, this study investigates co-located NO2 and CO satellite retrievals from TROPOMI over the megacities of Tehran, Mexico City, Cairo, Riyadh, Lahore and Los Angeles. The TROPOMI instrument was successfully launched by the European Space Agency on 13 October, 2017. It measures atmospheric trace gases with daily coverage and a spatial resolution of 7x7 km2. At this resolution, TROPOMI detects hotspots of CO and NO2 pollution over megacities in single satellite overpasses. The Upwind Background and Plume rotation methods are applied to quantify and evaluate TROPOMI derived &#8710;NO2/&#8710;CO ratios. TROPOMI derived &#8710;NO2/&#8710;CO ratios show a strong correlation (r = 0.85 and 0.7) with emission ratios from the Emission Database for Global Atmospheric Research (EDGAR v4.3.2) and Monitoring Atmospheric Chemistry and Climate and CityZen (MACCity) 2018, with the highest ratio for Riyadh and lowest for Lahore. Inventory-derived emission ratios are larger than TROPOMI-derived total column ratios by 60 to 80%. As we will show, this can largely be explained by the limited lifetime of NO2 and the different vertical sensitivity of the TROPOMI NO2 and CO column retrievals. Taking this into account, TROPOMI retrieved emission ratios are generally within 10 to 25% of MACCity. However, larger differences, up to 80%, are found with EDGAR. For Los Angeles, both inventories overestimate NO2/CO ratios compared with TROPOMI. Validation using the air quality monitoring network of Los Angeles supports the lower &#8710;NO2/&#8710;CO ratios inferred from TROPOMI, indicating that burning efficiencies in Los Angeles are indeed poorer than indicated by the inventories.&#160;

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The Effects of COVID-19 Lockdown on Air Quality in Macedonia

Open Access Macedonian Journal of Medical Sciences ◽

10.3889/oamjms.2020.5455 ◽

2020 ◽

Vol 8 (T1) ◽

pp. 353-362

Author(s):

Mirjana Dimovska ◽

Dragan Gjorgjev

Keyword(s):

Carbon Monoxide ◽

Air Quality ◽

Nitrogen Dioxide ◽

Negative Impact ◽

European Space Agency ◽

Monitoring Network ◽

Air Pollutant ◽

Economic Activities ◽

Economic Implications ◽

The Impact

BACKGROUND: Faced with the novel coronavirus outbreak (2019-nCoV), various urgent and coordinated actions have been taken worldwide to reduce spread of the disease. Slowing down economic activities, transportation, restrictions of the human public gatherings, and interaction resulted with a tremendous decline in air pollutant concentration especially in nitrogen dioxide, registered by National Aeronautics and Space Administration and European Space Agency satellites. AIM: The aim of the study was to assess the impact of COVID-19 lockdown conditions on the air quality in selected cities in Macedonia. METHODS: Daily mean concentration of the particulate matter (PM10 and PM2.5), nitrogen dioxide, ozone, and carbon monoxide measured in the national air quality monitoring network, was analyzed separately comparing following periods: past week of February 2020 to the end of May 2020 with the same period in 2017–2019. Depending on the data distribution, parametric independent-samples t-test or nonparametric Mann–Whitney U-test was run to determine if there were differences in the pollutants concentration during the COVID-19 and non-COVID-19 period. RESULTS: Implementation of strict restrictions of the movement along with reduced economic activities and vehicular transport, led to notable decrement of air pollutant concentrations. We have found an evident decrease in the concentration levels of all pollutants measured during COVID-19 period in 2020, compared to those from 2017 to 2019 with exceptions for PM2.5 in Kumanovo and carbon monoxide in Skopje (7% and 3% higher concentration). The most notable decrement was for NO2, with a concentration 5–31% lower during COVID-19 period. CONCLUSIONS: Although beneficial to human health, there is a need to assess economic implications of the lockdown that could have a negative impact on the health as well.

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First year of real-time VOC measurements at the SIRTA facility (Paris region, France): diurnal and seasonal variabilities, impact of lockdowns on air quality

10.5194/egusphere-egu21-8643 ◽

2021 ◽

Author(s):

Leïla Simon ◽

Valérie Gros ◽

Jean-Eudes Petit ◽

François Truong ◽

Roland Sarda-Esteve ◽

...

Keyword(s):

Air Quality ◽

Atmospheric Chemistry ◽

Seasonal Variability ◽

Anthropogenic Sources ◽

First Year ◽

Good Representation ◽

Atmospheric Measurements ◽

Paris Region ◽

The Impact

Volatile Organic Compounds (VOCs) have direct influences on air quality and climate. They also play a key role in atmospheric chemistry, as they are precursors of secondary pollutants, such as ozone (O3) and secondary organic aerosols (SOA).Long-term datasets of in-situ atmospheric measurements are crucial to characterize the variability of atmospheric chemical composition. Online and continuous measurements of O3, NOx and aerosols have been achieved at the SIRTA-ACTRIS facility (Paris region, France), since 2012. Regarding VOCs, they have been measured there for several years thanks to bi-weekly samplings followed by offline Gas Chromatography analysis. However, this method doesn&#8217;t provide a good representation of the temporal variability of VOC concentrations. To tackle this issue, online VOC measurements using a Proton-Transfer-Reaction Quadrupole Mass-Spectrometer (PTR-Q-MS) have been started in January 2020.The dataset acquired during the first year of online VOC measurements is analyzed, which gives insights on VOC seasonal variability. The additional long-term datasets obtained from co-located measurements (O3, NOx, aerosol physical and chemical properties, meteorological parameters) are also used for the sake of this study.Due to Covid-19 pandemic, the year 2020 notably comprised a total lockdown in France in Spring, and a lighter one in Autumn. Therefore, a focus can be made on the impact of these lockdowns on the VOC variability and sources. To this end, the diurnal cycles of VOCs considered markers for anthropogenic sources are carefully investigated. Results notably indicate that markers for traffic and wood burning sources behave quite differently during the Spring lockdown in comparison to the other periods. A source apportionment analysis using positive matrix factorization allows to further document the seasonal variability of VOC sources and the impacts on air quality associated with the lockdown measures.

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The impact of traffic emissions on atmospheric ozone and OH: results from QUANTIFY

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-3113-2009 ◽

2009 ◽

Vol 9 (9) ◽

pp. 3113-3136 ◽

Cited By ~ 116

Author(s):

P. Hoor ◽

J. Borken-Kleefeld ◽

D. Caro ◽

O. Dessens ◽

O. Endresen ◽

...

Keyword(s):

Atmospheric Chemistry ◽

Lower Troposphere ◽

Local Maximum ◽

Traffic Emissions ◽

Transport Sector ◽

Maximum Effect ◽

Ship Emissions ◽

Emission Data ◽

Global Emission ◽

The Impact

Abstract. To estimate the impact of emissions by road, aircraft and ship traffic on ozone and OH in the present-day atmosphere six different atmospheric chemistry models have been used. Based on newly developed global emission inventories for road, ship and aircraft emission data sets each model performed sensitivity simulations reducing the emissions of each transport sector by 5%. The model results indicate that on global annual average lower tropospheric ozone responds most sensitive to ship emissions (50.6%±10.9% of the total traffic induced perturbation), followed by road (36.7%±9.3%) and aircraft exhausts (12.7%±2.9%), respectively. In the northern upper troposphere between 200–300 hPa at 30–60° N the maximum impact from road and ship are 93% and 73% of the maximum effect of aircraft, respectively. The latter is 0.185 ppbv for ozone (for the 5% case) or 3.69 ppbv when scaling to 100%. On the global average the impact of road even dominates in the UTLS-region. The sensitivity of ozone formation per NOx molecule emitted is highest for aircraft exhausts. The local maximum effect of the summed traffic emissions on the ozone column predicted by the models is 0.2 DU and occurs over the northern subtropical Atlantic extending to central Europe. Below 800 hPa both ozone and OH respond most sensitively to ship emissions in the marine lower troposphere over the Atlantic. Based on the 5% perturbation the effect on ozone can exceed 0.6% close to the marine surface (global zonal mean) which is 80% of the total traffic induced ozone perturbation. In the southern hemisphere ship emissions contribute relatively strongly to the total ozone perturbation by 60%–80% throughout the year. Methane lifetime changes against OH are affected strongest by ship emissions up to 0.21 (± 0.05)%, followed by road (0.08 (±0.01)%) and air traffic (0.05 (± 0.02)%). Based on the full scale ozone and methane perturbations positive radiative forcings were calculated for road emissions (7.3±6.2 mWm−2) and for aviation (2.9±2.3 mWm−2). Ship induced methane lifetime changes dominate over the ozone forcing and therefore lead to a net negative forcing (−25.5±13.2 mWm−2).

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Spaceborne monitoring of CO2 emissions from large cities and the impact of aerosols

10.5194/egusphere-egu2020-20599 ◽

2020 ◽

Author(s):

Sander Houweling ◽

Jochen Landgraf ◽

Friedemann Reum ◽

Hein van Heck ◽

Wei Tao ◽

...

Keyword(s):

Co2 Emissions ◽

European Space Agency ◽

Monitoring Network ◽

Atmospheric Measurements ◽

Large Cities ◽

Anthropogenic Co2 ◽

Space Agency ◽

Spatial Coverage ◽

Spaceborne Monitoring ◽

The Impact

International agreements to reduce CO2 emissions call for an independent mechanism for evaluating the compliance with emission reduction targets. Atmospheric measurements can provide important information in support of this goal. However, to do this globally requires a drastic expansion of the existing monitoring network, using a combination of surface measurements and satellites. CO2 sensing satellites can deliver the required spatial coverage, filling in the gaps that are difficult to cover on ground. However, to reach the accuracy that is required for monitoring CO2 from space is a challenge, and even more so for anthropogenic CO2.The European space agency is preparing for the launch of a constellation of satellites for monitoring anthropogenic CO2 within the Copernicus program, starting in 2025. Scientific support studies have been carried out to define this mission in terms of payload and observational requirements. We report on the AeroCarb study, which investigated the impact retrieval errors due to aerosols in CO2 plumes downwind of large cities, and the potential benefit of an onboard aerosol sensor to help mitigate such errors. In this study, CO2 and aerosol plumes have been simulated at high-resolution for the cities of Berlin and Beijing. The impact of aerosol scattering on spaceborne CO2 measurements has been assessed using a combined CO2-aerosol retrieval scheme, with and without the use of an onboard multi-angular spectropolarimeter (MAP) for measuring aerosols. The results have been used to quantify the accuracy at which the CO2 emissions of Berlin and Beijing can be quantified using inverse modelling and the impact of aerosols depending on the chosen satellite payload.&#160;In this presentation we summarize the outcome of this study, and discuss the implications for the space borne monitoring of anthropogenic CO2 emissions from large cities.

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Temperature response measurements from eucalypts give insight into the impact of Australian isoprene emissions on air quality in 2050

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-6193-2020 ◽

2020 ◽

Vol 20 (10) ◽

pp. 6193-6206

Author(s):

Kathryn M. Emmerson ◽

Malcolm Possell ◽

Michael J. Aspinwall ◽

Sebastian Pfautsch ◽

Mark G. Tjoelker

Keyword(s):

Air Quality ◽

Transport Model ◽

Temperature Response ◽

Emission Factors ◽

Eucalyptus Species ◽

Chemical Transport Model ◽

Mixing Ratios ◽

The Impact ◽

Temperature Responses ◽

Insight Into

Abstract. Predicting future air quality in Australian cities dominated by eucalypt emissions requires an understanding of their emission potentials in a warmer climate. Here we measure the temperature response in isoprene emissions from saplings of four different Eucalyptus species grown under current and future average summertime temperature conditions. The future conditions represent a 2050 climate under Representative Concentration Pathway 8.5, with average daytime temperatures of 294.5 K. Ramping the temperature from 293 to 328 K resulted in these eucalypts emitting isoprene at temperatures 4–9 K higher than the default maximum emission temperature in the Model of Emissions of Gases and Aerosols from Nature (MEGAN). New basal emission rate measurements were obtained at the standard conditions of 303 K leaf temperature and 1000 µmol m−2 s−1 photosynthetically active radiation and converted into landscape emission factors. We applied the eucalypt temperature responses and emission factors to Australian trees within MEGAN and ran the CSIRO Chemical Transport Model for three summertime campaigns in Australia. Compared to the default model, the new temperature responses resulted in less isoprene emission in the morning and more during hot afternoons, improving the statistical fit of modelled to observed ambient isoprene. Compared to current conditions, an additional 2 ppb of isoprene is predicted in 2050, causing hourly increases up to 21 ppb of ozone and 24-hourly increases of 0.4 µg m−3 of aerosol in Sydney. A 550 ppm CO2 atmosphere in 2050 mitigates these peak Sydney ozone mixing ratios by 4 ppb. Nevertheless, these forecasted increases in ozone are up to one-fifth of the hourly Australian air quality limit, suggesting that anthropogenic NOx should be further reduced to maintain healthy air quality in future.

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Wood Smoke Impact on Particulate Matter (PM)

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.881-883.9 ◽

2014 ◽

Vol 881-883 ◽

pp. 9-12

Author(s):

Peng Ge

Keyword(s):

Particulate Matter ◽

Tree Species ◽

Sustainable Use ◽

Emission Factors ◽

Wood Smoke ◽

Wood Combustion ◽

Emission Data ◽

Different Types ◽

The Impact ◽

Emission Ratios

The emission factors and emission profiles of wood combustion tracers of different wood types were assessed. Emission profiles are additionally assessed for two advanced oven/boiler types. The emission profiles and emission ratios of wood smoke tracers to the PM emission of wood fires for the major tree species were established. From this a wood smoke profile will be derived which will be used to assess the impact of wood smoke to selected PM10 and PM2.5 sampling sites. Furthermore, using the energy-normalised PM mass emission data from different types of wood combustion appliances PM reduction scenarios will be assessed with the goal of a sustainable use of wood or wood-based fuels.

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The impact of sudden stratospheric warmings (SSWs) on UTLS composition, local radiative effects and air quality

10.5194/egusphere-egu2020-3545 ◽

2020 ◽

Author(s):

Ryan Williams ◽

Michaela Hegglin ◽

Patrick Jöckel ◽

Hella Garny ◽

Keith Shine ◽

...

Keyword(s):

Air Quality ◽

Atmospheric Chemistry ◽

Large Scale ◽

Lower Stratosphere ◽

Weather Prediction ◽

Onset Date ◽

Identification Algorithm ◽

Heating Rates ◽

Transport Pathways ◽

The Impact

Midwinter sudden stratospheric warmings (SSWs), characterised by the reversal of the temperature gradient poleward of 60&#176;N and the 10 hPa climatological zonal mean wind from westerly to easterly at 60&#176;N, are known to have pronounced impacts on tropospheric circulation which lead to regional changes in temperature, precipitation and other meteorological variables. Such abrupt events are furthermore known to be associated with large-scale changes in the distribution of stratospheric chemistry constituents, such as ozone (O3) and water vapour (H2O), although the implications for stratosphere-troposphere exchange (STE) have not been previously investigated. The evolution of O3 and H2O anomalies during an SSW life cycle are first examined from the surface up to 1 hPa using specified-dynamics simulations from the European Centre for Medium-Range Weather Forecasts &#8211; Hamburg (ECHAM)/Modular Earth Submodel System (MESSy) Atmospheric Chemistry (EMAC) model over the period 1979-2013. We show that significant positive anomalies in O3 occur around the onset of an SSW in the middle to lower stratosphere, with persistence timescales of around 50 days in the upper troposphere-lower stratosphere (UTLS). Similarly, we find significant H2O anomalies in the lowermost stratosphere (&#177; 25 %) for up to 75 days. The extent and magnitude of the anomalies are largely confirmed in both Copernicus Atmospheric Monitoring Service (CAMS) reanalysis and ozonesonde measurements at five different Arctic stations. These chemical perturbations result in local temperature changes of up to 2 K, which may impact numerical weather prediction (NWP) of the tropospheric response to SSWs. Evaluation of the vertical residual velocity (w*) support the notion of transport changes being the driver of the temporal evolution of the anomalies. Using a stratospheric-tagged O3 tracer, a signal for enhanced STE of ozone is subsequently inferred (~ 5-10 %), which is maximised around 50 days after the SSW onset date. We furthermore attempt to elucidate STE transport pathways using a tropopause fold identification algorithm applied to ERA-Interim during this period, and assess such changes in folding frequency and distribution during such events. Our results highlight that SSWs can induce significantly disturbed O3 and H2O distributions in the UTLS, leading to enhanced STE of O3, with potentially significant implications for radiative fluxes, atmospheric heating rates and air quality.

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Polyalthia longifolia (False Ashoka) is an ideal choice for better air quality at kerbside locations

10.5194/egusphere-egu2020-922 ◽

2020 ◽

Author(s):

Vidit Parkar ◽

Savita Datta ◽

Haseeb Hakkim ◽

Ashish Kumar ◽

Muhammed Shabin ◽

...

Keyword(s):

Air Quality ◽

Stomatal Conductance ◽

Atmospheric Chemistry ◽

Air Pollutants ◽

Ambient Air ◽

Area Index ◽

Mixing Ratios ◽

Post Monsoon ◽

Polyalthia Longifolia ◽

The Impact

Tropospheric ozone is a major pollutant and it is harmful for humans at sustained exposures of 40 ppb or more in ambient air. In this study we calibrate the deposition of ozone for stomatal exchange (DO3SE) model for Polyalthia longifolia (False Ashoka), a tree that accounts for 5-20% of the urban plantations in Indian cities and subsequently use the model to estimate not only the stomatal O3 uptake by this tree but also its capability to sequester other criteria air pollutants. We discuss the impact of planting this tree on ozone precursors NOx and VOCs in a roadside plantation scenario for mitigating air pollution.Stomatal conductance of Polyalthia longifolia was measured, using a SC-1 Leaf Porometer, at IISER Mohali-Punjab in the NW-IGP (Northwest Indo-Gangetic Plane) which has a sub-tropical dry climate. Stomatal conductance was measured during all the four (Summer, Monsoon, Post-Monsoon, Winter) seasons, while BVOC emission fluxes were quantified using a dynamic plant cuvette during post monsoon, winter and summer season. We use ambient mixing ratios of ozone, NO, NO2, SO2 and O3 in combination with the meteorological parameters such as temperature, RH, soil moisture and photosynthetically active radiation (PAR) from the IISER Mohali Atmospheric chemistry facility to quantify Polyalthia longifolia roadside plantations&#8217; impact on urban air quality through stomatal uptake of air pollutants (primarily NO, NO2 and O3) and BVOC emissions. Polyalthia longifolia displays a number of very interesting characteristics that include being a low isoprene and monoterpene emitter, having an extremely high leaf area index thanks to its height, straight shape and dense canopy. It displays extreme resistance to drought and high vapour pressure deficits in summer allowing stomatal uptake of pollutants and evaporative cooling to continue even under unfavourable meteorological conditions.

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Urban particulate matter pollution: a tale of five cities

Faraday Discussions ◽

10.1039/c5fd00212e ◽

2016 ◽

Vol 189 ◽

pp. 277-290 ◽

Cited By ~ 13

Author(s):

Spyros N. Pandis ◽

Ksakousti Skyllakou ◽

Kalliopi Florou ◽

Evangelia Kostenidou ◽

Christos Kaltsonoudis ◽

...

Keyword(s):

Particulate Matter ◽

Air Quality ◽

Los Angeles ◽

Atmospheric Chemistry ◽

Urban Areas ◽

Fine Particulate Matter ◽

The United States ◽

Chemical Signatures ◽

Range Transport

Five case studies (Athens and Paris in Europe, Pittsburgh and Los Angeles in the United States, and Mexico City in Central America) are used to gain insights into the changing levels, sources, and role of atmospheric chemical processes in air quality in large urban areas as they develop technologically. Fine particulate matter is the focus of our analysis. In all cases reductions of emissions by industrial and transportation sources have resulted in significant improvements in air quality during the last few decades. However, these changes have resulted in the increasing importance of secondary particulate matter (PM) which dominates over primary in most cases. At the same time, long range transport of secondary PM from sources located hundreds of kilometres from the cities is becoming a bigger contributor to the urban PM levels in all seasons. “Non-traditional” sources including cooking, and residential and agricultural biomass burning contribute an increasing fraction of the now reduced fine PM levels. Atmospheric chemistry is found to change the chemical signatures of a number of these sources relatively fast both during the day and night, complicating the corresponding source apportionment.

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