Verification of expected trends in urban traffic NOx emissions from long-term measurements of ambient NO2 concentrations in urban air

1996 ◽  
Vol 189-190 ◽  
pp. 213-220 ◽  
Author(s):  
Å. Sjödin ◽  
K. Sjöberg ◽  
P.A. Svanberg ◽  
H. Backström
Keyword(s):  
Urban Traffic ◽  
Urban Air ◽  
Nox Emissions

Long-term association between urban air ventilation and mortality in Hong Kong

2021 ◽  
Vol 197 ◽  
pp. 111000
Author(s):  
Pin Wang ◽  
William B. Goggins ◽  
Yuan Shi ◽  
Xuyi Zhang ◽  
Chao Ren ◽  
...  
Keyword(s):  
Hong Kong ◽  
Urban Air ◽  
Air Ventilation

scholarly journals Top-Down NOX Emissions of European Cities Based on the Downwind Plume of Modelled and Space-Borne Tropospheric NO2 Columns

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2893 ◽  
Author(s):  
Willem W. Verstraeten ◽  
Klaas Folkert Boersma ◽  
John Douros ◽  
Jason E. Williams ◽  
Henk Eskes ◽  
...  
Keyword(s):  
Urban Areas ◽  
Transport Model ◽  
Nox Emissions ◽  
Inventory Data ◽  
Ozone Monitoring Instrument ◽  
Top Down ◽  
Chemistry Transport Model ◽  
European Cities ◽  
Tropospheric No2

Top-down estimates of surface NOX emissions were derived for 23 European cities based on the downwind plume decay of tropospheric nitrogen dioxide (NO2) columns from the LOTOS-EUROS (Long Term Ozone Simulation-European Ozone Simulation) chemistry transport model (CTM) and from Ozone Monitoring Instrument (OMI) satellite retrievals, averaged for the summertime period (April–September) during 2013. Here we show that the top-down NOX emissions derived from LOTOS-EUROS for European urban areas agree well with the bottom-up NOX emissions from the MACC-III inventory data (R2 = 0.88) driving the CTM demonstrating the potential of this method. OMI top-down NOX emissions over the 23 European cities are generally lower compared with the MACC-III emissions and their correlation is slightly lower (R2 = 0.79). The uncertainty on the derived NO2 lifetimes and NOX emissions are on average ~55% for OMI and ~63% for LOTOS-EUROS data. The downwind NO2 plume method applied on both LOTOS-EUROS and OMI tropospheric NO2 columns allows to estimate NOX emissions from urban areas, demonstrating that this is a useful method for real-time updates of urban NOX emissions with reasonable accuracy.

Fingerprints of a New Normal Urban Air Quality in S5P TROPOMI Tropospheric NO2 Observations

2021 ◽  
Author(s):  
Shobha Kondragunta
Keyword(s):  
United States ◽  
Air Quality ◽  
Unemployment Rate ◽  
Power Plants ◽  
The United States ◽  
Urban Air Quality ◽  
Urban Air ◽  
Nox Emissions ◽  
Percentage Increase ◽  
New Normal

<p>Most countries around the world took actions to control COVID-19 spread that included social distancing, limiting air and ground travel, closing schools, suspending sports leagues, closing factories etc., leading to  economic shutdown. The reduced traffic and human movement compared to Business as Usual (BAU) scenario was tracked by Apple and Android cellphone use; the data showed substantial reductions in mobility in most metropolitan areas.  We analyzed reductions in on-road mobile NOx emissions from light and heavy duty vehicles in four major metropolitan and one rural areas in the United States that showed a reduction in NOx mobile emissions from 9% to 19% between February and March at the onset of lockdown in the middle of March; between March and April, the mobile NOx emissions dropped further by 8% to 31% when lockdown measures were the most stringiest.  These precipitous drops in NOx emissions correlated well with tropospheric NO<sub>2</sub> column amount observed by Sentinel 5 Precursor TROPospheric Ozone Monitoring Instrument (S5P TROPOMI).  Further, the changes in TROPOMI tropospheric NO<sub>2</sub> across the continental U.S. between 2020 and 2019 correlated well with changes in on-road NOx emissions (r=0.78) but correlated weakly with changes in emissions from the power plants (r=0.44). These findings confirm that power plants are no longer the major source of NO<sub>2</sub> in the United States. We also examined correlation between increase in unemployment rate between 2020 and 2019 to decrease in tropospheric NO<sub>2</sub> amount.  The negative correlation indicates that with increased unemployment rate combined with telework policies across the nation for non-essential workers, the NO<sub>2</sub> values decreased at the rate of 0.8 µmoles/m<sup>2</sup> decrease per unit percentage increase in unemployment rate.  There is a substantial amount of scatter in the data with some cities such as Atlanta, Dallas, and Houston showing no noticeable trend in tropospheric NO<sub>2</sub> changes during the time period when unemployment rate increased from 6% to 12%.   We examined the trends in on-road and power plant emissions for five different locations (four urban areas and one rural area) and show that the changes in NOx emissions during the lockdown are detectable in TROPOMI tropNO2 data, the economic indicators are consistent with emissions changes, and the trends reversing with the removal of lockdown measures in the major metro areas have not come back to pre-pandemic levels.  The COVID-19 pandemic experience has provided the scientific community an opportunity to identify emissions reductions scenarios that created a new normal for urban air quality and if the environmental protection agencies should look at this new normal as a guidance for instituting new policies. </p>

scholarly journals Effects of meteorology and emissions on urban air quality: a quantitative statistical approach to long-term records (1999–2016) in Seoul, South Korea

2018 ◽  
Vol 18 (21) ◽  
pp. 16121-16137 ◽  
Author(s):  
Jihoon Seo ◽  
Doo-Sun R. Park ◽  
Jin Young Kim ◽  
Daeok Youn ◽  
Yong Bin Lim ◽  
...  
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
South Korea ◽  
Meteorological Conditions ◽  
Meteorological Variables ◽  
Urban Air ◽  
Short Term ◽  
Long Term Trends ◽  
Local Emissions

Abstract. Together with emissions of air pollutants and precursors, meteorological conditions play important roles in local air quality through accumulation or ventilation, regional transport, and atmospheric chemistry. In this study, we extensively investigated multi-timescale meteorological effects on the urban air pollution using the long-term measurements data of PM10, SO2, NO2, CO, and O3 and meteorological variables over the period of 1999–2016 in Seoul, South Korea. The long-term air quality data were decomposed into trend-free short-term components and long-term trends by the Kolmogorov–Zurbenko filter, and the effects of meteorology and emissions were quantitatively isolated using a multiple linear regression with meteorological variables. In terms of short-term variability, intercorrelations among the pollutants and meteorological variables and composite analysis of synoptic meteorological fields exhibited that the warm and stagnant conditions in the migratory high-pressure system are related to the high PM10 and primary pollutant, while the strong irradiance and low NO2 by high winds at the rear of a cyclone are related to the high O3. In terms of long-term trends, decrease in PM10 (−1.75 µg m−3 yr−1) and increase in O3 (+0.88 ppb yr−1) in Seoul were largely contributed by the meteorology-related trends (−0.94 µg m−3 yr−1 for PM10 and +0.47 ppb yr−1 for O3), which were attributable to the subregional-scale wind speed increase. Comparisons with estimated local emissions and socioeconomic indices like gross domestic product (GDP) growth and fuel consumptions indicate probable influences of the 2008 global economic recession as well as the enforced regulations from the mid-2000s on the emission-related trends of PM10 and other primary pollutants. Change rates of local emissions and the transport term of long-term components calculated by the tracer continuity equation revealed a decrease in contributions of local emissions to the primary pollutants including PM10 and an increase in contributions of local secondary productions to O3. The present results not only reveal an important role of synoptic meteorological conditions on the episodic air pollution events but also give insights into the practical effects of environmental policies and regulations on the long-term air pollution trends. As a complementary approach to the chemical transport modeling, this study will provide a scientific background for developing and improving effective air quality management strategy in Seoul and its metropolitan area.

Long-term urban air pollution exposures and chronic kidney disease in the elderly population in Taiwan

2016 ◽  
Vol 2016 (1) ◽  
Author(s):  
Szu-Ying Chen* ◽  
Da-Chen Chu ◽  
Jui-Huan Lee ◽  
YA-RU YANG ◽  
Chang-Chuan Chan
Keyword(s):  
Chronic Kidney Disease ◽  
Air Pollution ◽  
Kidney Disease ◽  
Elderly Population ◽  
Urban Air Pollution ◽  
The Elderly ◽  
Urban Air

scholarly journals Ozone response to emission reductions in the southeastern United States

2018 ◽  
Vol 18 (11) ◽  
pp. 8183-8202 ◽  
Author(s):  
Charles L. Blanchard ◽  
George M. Hidy
Keyword(s):  
Environmental Protection Agency ◽  
Study Data ◽  
Nox Emissions ◽  
Emission Rates ◽  
Emission Reductions ◽  
Mixing Ratios ◽  
Southeastern Us ◽  
Surface Measurements ◽  
Nitrate Deposition

Abstract. Ozone (O3) formation in the southeastern US is studied in relation to nitrogen oxide (NOx) emissions using long-term (1990s–2015) surface measurements of the Southeastern Aerosol Research and Characterization (SEARCH) network, U.S. Environmental Protection Agency (EPA) O3 measurements, and EPA Clean Air Status and Trends Network (CASTNET) nitrate deposition data. Annual fourth-highest daily peak 8 h O3 mixing ratios at EPA monitoring sites in Georgia, Alabama, and Mississippi exhibit statistically significant (p < 0.0001) linear correlations with annual NOx emissions in those states between 1996 and 2015. The annual fourth-highest daily peak 8 h O3 mixing ratios declined toward values of ∼ 45–50 ppbv and monthly O3 maxima decreased at rates averaging ∼ 1–1.5 ppbv yr−1. Mean annual total oxidized nitrogen (NOy) mixing ratios at SEARCH sites declined in proportion to NOx emission reductions. CASTNET data show declining wet and dry nitrate deposition since the late 1990s, with total (wet plus dry) nitrate deposition fluxes decreasing linearly in proportion to reductions of NOx emissions by ∼ 60 % in Alabama and Georgia. Annual nitrate deposition rates at Georgia and Alabama CASTNET sites correspond to 30 % of Georgia emission rates and 36 % of Alabama emission rates, respectively. The fraction of NOx emissions lost to deposition has not changed. SEARCH and CASTNET sites exhibit downward trends in mean annual nitric acid (HNO3) concentrations. Observed relationships of O3 to NOz (NOy–NOx) support past model predictions of increases in cycling of NO and increasing responsiveness of O3 to NOx. The study data provide a long-term record that can be used to examine the accuracy of process relationships embedded in modeling efforts. Quantifying observed O3 trends and relating them to reductions in ambient NOy species concentrations offers key insights into processes of general relevance to air quality management and provides important information supporting strategies for reducing O3 mixing ratios.

scholarly journals LONG-TERM TRACKING OF A SPECIFIC VEHICLE USING AIRBORNE OPTICAL CAMERA SYSTEMS

2016 ◽  
Vol XLI-B2 ◽  
pp. 521-525
Author(s):  
F. Kurz ◽  
D. Rosenbaum ◽  
H. Runge ◽  
D. Cerra ◽  
G. Mattyus ◽  
...  
Keyword(s):  
Low Cost ◽  
Basic Density ◽  
Urban Traffic ◽  
Frame Rate ◽  
Transmission Model ◽  
Cell Transmission Model ◽  
Good Correspondence ◽  
Congested Traffic ◽  
Camera Systems

In this paper we present two low cost, airborne sensor systems capable of long-term vehicle tracking. Based on the properties of the sensors, a method for automatic real-time, long-term tracking of individual vehicles is presented. This combines the detection and tracking of the vehicle in low frame rate image sequences and applies the lagged Cell Transmission Model (CTM) to handle longer tracking outages occurring in complex traffic situations, e.g. tunnels. The CTM model uses the traffic conditions in the proximities of the target vehicle and estimates its motion to predict the position where it reappears. <br><br> The method is validated on an airborne image sequence acquired from a helicopter. Several reference vehicles are tracked within a range of <i>500m</i> in a complex urban traffic situation. An artificial tracking outage of <i>240m</i> is simulated, which is handled by the CTM. For this, all the vehicles in the close proximity are automatically detected and tracked to estimate the basic density-flow relations of the CTM model. Finally, the real and simulated trajectories of the reference vehicles in the outage are compared showing good correspondence also in congested traffic situations.

scholarly journals Effect of regional precursor emission controls on long-range ozone transport – Part 2: steady-state changes in ozone air quality and impacts on human mortality

2009 ◽  
Vol 9 (2) ◽  
pp. 7079-7113 ◽  
Author(s):  
J. J. West ◽  
V. Naik ◽  
L. W. Horowitz ◽  
A. M. Fiore
Keyword(s):  
Air Quality ◽  
Long Range ◽  
Surface Ozone ◽  
Emission Region ◽  
Nox Emissions ◽  
Short Term ◽  
Human Mortality ◽  
World Regions ◽  
Ozone Precursor

Abstract. Large-scale changes in ozone precursor emissions affect ozone directly in the short term, and also affect methane, which in turn causes long-term changes in ozone that affect surface ozone air quality. Here we assess the effects of changes in ozone precursor emissions on the long-term change in surface ozone via methane, as a function of the emission region, by modeling 10% reductions in anthropogenic nitrogen oxide (NOx) emissions from each of nine world regions. Reductions in NOx emissions from all world regions increase methane and long-term surface ozone. While this long-term increase is small compared to the intra-regional short-term ozone decrease, it is comparable to or larger than the short-term inter-continental ozone decrease for some source-receptor pairs. The increase in methane and long-term surface ozone per ton of NOx reduced is greatest in tropical and Southern Hemisphere regions, exceeding that from temperate Northern Hemisphere regions by roughly a factor of ten. We also assess changes in premature ozone-related human mortality associated with regional precursor reductions and long-range transport, showing that for 10% regional NOx reductions, the strongest inter-regional influence is for emissions from Europe affecting mortalities in Africa. Reductions of NOx in North America, Europe, the Former Soviet Union, and Australia are shown to reduce more mortalities outside of the source regions than within. Among world regions, NOx reductions in India cause the greatest number of avoided mortalities per ton, mainly in India itself. Finally, by increasing global methane, NOx reductions in one hemisphere tend to cause long-term increases in ozone concentration and mortalities in the opposite hemisphere. Reducing emissions of methane, and to a lesser extent carbon monoxide and non-methane volatile organic compounds, alongside NOx reductions would avoid this disbenefit.

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