Mobile Emissions Research Articles

Experimental Study of Moving Truck Emissions on Inter-City National Road: A Case Study of Malino Main Road

The research aimed to determine exhaust emission and speed of the truck when moving. Measurements were made using a mobile emission analyzer that absorbed emission from truck exhaust. Data collection was done by putting mobile emission analyzer on the right side of the vehicle which absorbs 5 emissions of approximately 5 minutes. The relationship of exhaust emission and speed uses the polynomial model of the average value of exhaust emission and speed. The reliability of mobile emission analyzer uses the multiplier factor to solve the data difference between mobile emission analyzer and Bosowa equipment. The results of research indicate emission of CO2, NOx, Smoke, CO, and HC forming driving cycle pattern. This pattern shows the pattern follows parabola tendency. Emission on damaged road is higher than good road although the emission values are not much different. However, the value of emission of Smoke is relatively equal in both road conditions.

Systematic Identification and Prioritization of Communities Impacted by Residential Woodsmoke in British Columbia, Canada

Background: Residential woodsmoke is an under-regulated source of fine particulate matter (PM2.5), often surpassing mobile and industrial emissions in rural communities in North America and elsewhere. In the province of British Columbia (BC), Canada, many municipalities are hesitant to adopt stricter regulations for residential wood burning without empirical evidence that smoke is affecting local air quality. The objective of this study was to develop a retrospective algorithm that uses 1-hour PM2.5 concentrations and daily temperature data to identify smoky days in order to prioritize communities by smoke impacts.Methods: Levoglucosan measurements from one of the smokiest communities were used to establish the most informative values for three algorithmic parameters: the daily standard deviation of 1-hour PM2.5 measurements; the daily mean temperature; and the daytime-to-nighttime ratio of PM2.5 concentrations. Alternate parameterizations were tested in 45 sensitivity analyses, and 23 smaller communities (populations < 80,000) were ranked by the number of smoky days identified within a 2-year period.Results: Using the most informative parameter values on the most recent two years of data for each community, the number of smoky days ranged from 5 to 277 out of 730. Heat maps visualizing seasonal and diurnal variation in PM2.5 concentrations showed clear differences between the higher- and lower-ranked communities. Some communities were sensitive to one or more of the parameters, but the overall rankings were consistent across the 45 sensitivity analyses.Conclusions: This information will allow stakeholder agencies to work with local governments on implementing appropriate intervention strategies for the most smoke-impacted communities. It was also used to identify communities for more detailed assessment using mobile monitoring.

Characterization of solid deposits from urea water solution injected into a hot gas test rig

Recent developments in mobile emission legislations have created an urgent need for effective ammonia preparation for Selective Catalytic Reduction (SCR) of nitrogen oxides from diesel exhaust. The present work deals with the problem of solid by-product formation from urea injected to the tailpipe as precursor for ammonia. A hot gas test rig is designed to perform experiments on deposit formation at well-defined operating conditions. Generated deposits are sampled for detailed analyses of topography and chemical composition. Dimensions and chemical decomposition kinetics of the samples are correlated with the respective operating conditions and reference data, which result from detailed analysis of the decomposition kinetics of urea water solution and pure by-products. Results show the influence of temperature and urea dosing strategy on the amount of generated deposits. Investigations on deposit composition reveal incompleteness of existing decomposition mechanisms and present data for further development of urea decomposition kinetics.

Future year ozone source attribution modeling study using CMAQ-ISAM

ABSTRACTTo achieve the current United States National Ambient Air Quality Standards (NAAQS) attainment level for ozone or particulate matter, current photochemical air quality models include tools to determine source apportionment and/or source sensitivity. Previous studies by the authors have used the Ozone and Particulate Matter Source Apportionment Technology and Higher-order Decoupled Direct Method probing tools in CAMx to investigate these source-receptor relationships for ozone. The recently available source apportionment for CMAQ, referred to as the Integrated Source Apportionment Method (ISAM), was used in this study to conduct future year (2030) source attribution modeling. The CMAQ-ISAM ozone source attribution results for selected cities across the U.S. showed boundary conditions were the dominant contributor to the future year highest July maximum daily 8-hour average (MDA8) ozone concentrations. Point sources were generally larger contributors in the eastern U.S. than in the western U.S. The contributions of on-road mobile emissions were around 5 ppb at most of the cities selected for analysis. Off-road mobile source contributions were around 20 ppb or nearly 30%. Since boundary conditions play an important role in future year ozone levels, it is important to characterize future year boundary conditions accurately. The current implementation of ISAM in CMAQ 5.0.2 requires significant computing resources for ozone source attribution, making it difficult to conduct long-term simulations for large domains. The computing requirements for PM source attribution are even more onerous. CMAQ 5.2 was released after this study was completed, and does not include ISAM. If an efficient version of ISAM becomes available, it could be used in long-term ozone and PM2.5 studies. Implications: Ozone source attribution results provide useful information on important emission source contribution categories and provide some initial guidance on future emission reduction strategies. This study explains a new source apportionment technique, CMAQ-ISAM, and compares it to CAMx OSAT. The techniques have similar results: ozone’s highest source contributor is boundary conditions, followed by point sources, then off-road mobile sources. The current version of ISAM in CMAQ 5.0.2 requires significant computing resources for ozone source attribution, while the computing requirements for PM source attribution are even more onerous. CMAQ 5.2 was released after this study was completed, and does not include ISAM.

Additional Benefits of Federal Air-Quality Rules: Model Estimates of Controllable Biogenic Secondary Organic Aerosol.

Atmospheric models that accurately describe the fate and transport of trace species for the right reasons aid in the development of effective air-quality management strategies that safeguard human health. Controllable emissions facilitate the formation of biogenic secondary organic aerosol (BSOA) to enhance the atmospheric fine particulate matter (PM2.5) burden. Previous modeling with the EPA's Community Multiscale Air Quality (CMAQ) model predicted that anthropogenic primary organic aerosol (POA) emissions had the greatest impact on BSOA. That experiment included formation processes involving semivolatile partitioning but not aerosol liquid water (ALW), a ubiquitous PM constituent. We conduct 17 summertime CMAQ simulations with updated chemistry and evaluate changes in BSOA due to the removal of individual pollutants and source sectors for the contiguous U.S. CMAQ predicts SO2 from electricity generating units, and mobile source NOX emissions have the largest impacts on BSOA. The removal of anthropogenic NOX, SO2, and POA emissions during the simulation reduces the nationally averaged BSOA by 23, 14, and 8% and PM2.5 by 9.2, 14, and 5.3%, respectively. ALW mass concentrations decrease by 10 and 35% in response to the removal of NOX and SO2 emissions. This work contributes chemical insight into ancillary benefits of Federal NOX and SO2 rules that concurrently reduce organic PM2.5 mass.

GEM-MACH-PAH (rev2488): a new high-resolution chemical transport model for North American polycyclic aromatic hydrocarbons and benzene

Abstract. Environment and Climate Change Canada's online air quality forecasting model, GEM-MACH, was extended to simulate atmospheric concentrations of benzene and seven polycyclic aromatic hydrocarbons (PAHs): phenanthrene, anthracene, fluoranthene, pyrene, benz(a)anthracene, chrysene, and benzo(a)pyrene. In the expanded model, benzene and PAHs are emitted from major point, area, and mobile sources, with emissions based on recent emission factors. Modelled PAHs undergo gas–particle partitioning (whereas benzene is only in the gas phase), atmospheric transport, oxidation, cloud processing, and dry and wet deposition. To represent PAH gas–particle partitioning, the Dachs–Eisenreich scheme was used, and we have improved gas–particle partitioning parameters based on an empirical analysis to get significantly better gas–particle partitioning results than the previous North American PAH model, AURAMS-PAH. Added process parametrizations include the particle phase benzo(a)pyrene reaction with ozone via the Kwamena scheme and gas-phase scavenging of PAHs by snow via vapour sorption to the snow surface. The resulting GEM-MACH-PAH model was used to generate the first online model simulations of PAH emissions, transport, chemical transformation, and deposition for a high-resolution domain (2.5 km grid cell spacing) in North America, centred on the PAH data-rich region of southern Ontario, Canada and the northeastern US. Model output for two seasons was compared to measurements from three monitoring networks spanning Canada and the US Average spring–summertime model results were found to be statistically unbiased from measurements of benzene and all seven PAHs. The same was true for the fall–winter seasonal mean, except for benzo(a)pyrene, which had a statistically significant positive bias. We present evidence that the benzo(a)pyrene results may be ameliorated via further improvements to particulate matter and oxidant processes and transport. Our analysis focused on four key components to the prediction of atmospheric PAH levels: spatial variability, sensitivity to mobile emissions, gas–particle partitioning, and wet deposition. Spatial variability of PAHs ∕ PM2.5 at a 2.5 km resolution was found to be comparable to measurements. Predicted ambient surface concentrations of benzene and the PAHs were found to be critically dependent on mobile emission factors, indicating the mobile emissions sector has a significant influence on ambient PAH levels in the study region. PAH wet deposition was overestimated due to additive precipitation biases in the model and the measurements. Our overall performance evaluation suggests that GEM-MACH-PAH can provide seasonal estimates for benzene and PAHs and is suitable for emissions scenario simulations.

Urban residential indoor volatile organic compounds in summer, Beijing: Profile, concentration and source characterization

Residential indoor exposure to volatile organic compounds (VOCs) is a major public health concern. However, the relevant pollution sources have not been well characterized in China. In this study, the 24-h integrated concentrations of 55 VOC species in 27 urban residences, Beijing were measured in the summer. The sources were characterized with positive matrix factorization (PMF) and general linear model (GLM). The most abundant species in terms of geometric mean concentration were formaldehyde (55.1 μg/m3), acetaldehyde (18.7 μg/m3), acetone (14.8 μg/m3), toluene (14.1 μg/m3), hexanal (13.8 μg/m3), n-hexadecane (8.9 μg/m3) and n-pentadecane (8.5 μg/m3). PMF generated 7 factors associated with VOC sources, including aldehydes from ozone-initiated secondary reactions, butyraldehyde from hydrolysis of building materials and furniture, wood flooring emission, wooden furniture emission, wall coverings emission, mobile emission and halogenated hydrocarbons of miscellaneous outdoor origin. GLM identified leather sofa as another source of indoor terpenes and formaldehyde. GLM also found composite wood flooring had stronger emission of VOCs than solid wood flooring, except 1,4-dichlorobenzene. A comparison with multiple studies across the world suggested that: (1) more intensive ozone-initiated secondary reactions resulted in the significantly higher indoor carbonyl concentrations in Beijing than in Japan and USA in the summer; (2) the indoor concentrations of benzene and C12-C17 alkanes were much higher in Beijing, due to the traffic conditions and prevalent use of wood flooring varnishing.

Reduction of atmospheric fine particle level by restricting the idling vehicles around a sensitive area

ABSTRACTAtmospheric particles are a major problem that could lead to harmful effects on human health, especially in densely populated urban areas. Chiayi is a typical city with very high population and traffic density, as well as being located at the downwind side of several pollution sources. Multiple contributors for PM2.5 (particulate matter with an aerodynamic diameter ≥2.5 μm) and ultrafine particles cause complicated air quality problems. This study focused on the inhibition of local emission sources by restricting the idling vehicles around a school area and evaluating the changes in surrounding atmospheric PM conditions. Two stationary sites were monitored, including a background site on the upwind side of the school and a campus site inside the school, to monitor the exposure level, before and after the idling prohibition. In the base condition, the PM2.5 mass concentrations were found to increase 15% from the background, whereas the nitrate (NO3−) content had a significant increase at the campus site. The anthropogenic metal contents in PM2.5 were higher at the campus site than the background site. Mobile emissions were found to be the most likely contributor to the school hot spot area by chemical mass balance modeling (CMB8.2). On the other hand, the PM2.5 in the school campus fell to only 2% after idling vehicle control, when the mobile source contribution reduced from 42.8% to 36.7%. The mobile monitoring also showed significant reductions in atmospheric PM2.5, PM0.1, polycyclic aromatic hydrocarbons (PAHs), and black carbon (BC) levels by 16.5%, 33.3%, 48.0%, and 11.5%, respectively. Consequently, the restriction of local idling emission was proven to significantly reduce PM and harmful pollutants in the hot spots around the school environment.Implications: The emission of idling vehicles strongly affects the levels of particles and relative pollutants in near-ground air around a school area. The PM2.5 mass concentration at a campus site increased from the background site by 15%, whereas NO3− and anthropogenic metals also significantly increased. Meanwhile, the PM2.5 contribution from mobile source in the campus increased 6.6% from the upwind site. An idling prohibition took place and showed impressive results. Reductions of PM2.5, ionic component, and non-natural metal contents were found after the idling prohibition. The mobile monitoring also pointed out a significant improvement with the spatial analysis of PM2.5, PM0.1, PAH, and black carbon concentrations. These findings are very useful to effectively improve the local air quality of a densely city during the rush hour.

Speed correlation and emission of truck vehicles on dynamic conditions

Concentration of CO2, NOx, smoke, CO, and HC released from several truck vehicles taken emission and speed data every 5 second through measurements using the mobile emission analyzer as an emission test vehicle that absorbs the gas from exhaust of sample vehicles. Implementation in field is to put emission test equipment on the right side of truck, which will absorb 5 gas compounds for 5 - 20 minutes with a view to knowing truck emissions of moving conditions by considering load factors. The sample vehicles are diesel-fueled trucks. From the research on gas emissions, it is generally found that the tendency that arises is the faster the vehicle speed then the CO2, NOx, Smoke, CO, and HC gases released will be greater or will increase as the vehicle speed increases. Thus, the relationship of CO2, NOx, smoke, CO, and HC concentration with vehicle speed is a linear relationship.

BASF to expand mobile emissions catalysts site in Sroda Slaska, Poland.

BASF to expand mobile emissions catalysts site in Sroda Slaska, Poland.

Relative Contribution of Different Source Categories to Ozone Exceedances in the Houston-Galveston-Brazoria Area

The goal of this study is to analyze the relative contribution of different emission source categories to ozone in the Houston-Galveston-Brazoria (HGB) area of Texas. Emission Processing System (EPS3) is used to prepare the emission files for five different source combination cases (Base case, Biogenic, Area + Biogenic, Mobile + Biogenic, Low-level Point + Biogenic). These emission files are used to perform photochemical modeling with Comprehensive Air Quality Model with Extensions (CAMx), and the results are analyzed with Visual Environment for Rich Data Interpretation (VERDI) tool. The daily maximum ozone concentrations and individual contributions of the source categories were analyzed over a 15-day study period between June 1-15, 2012, at three locations (University of Houston-Sugarland, Bayland Park and Conroe). Biogenic sources contributed an average of 49.7% ± 12.8%, 43.1% ± 12.0%, and 39.9% ± 9.28% at Sugarland, Bayland Park and Conroe sites respectively, indicating the significance of isoprene emissions from the vegetation in northeast Houston. On peak ozone days, contribution of Mobile + Biogenic source category averages about 80.1% ± 12.6%, 79.9% ± 6.50%, and 75.9% ± 10.9% at Sugarland, Bayland Park and Conroe sites respectively, indicating the dominance of mobile source NOX emissions and the necessity for regulatory focus on mobile source emissions control.

Short-term Effects of Ambient PM2.5 and PM2.5-10 on Mortality in Major Cities of Korea

ABSTRACT While many epidemiological studies have examined the health effects of different sizes of ambient particulate matter (PM), the findings have been mixed. PM is a heterogeneous mixture, and its chemical components differ by size, with more combustion related materials in the fine mode and more crustal materials in the coarse mode. This study estimates the risk of mortality associated with exposure to PM2.5 (particulate matter less than 2.5 µm in aerodynamic diameter) and PM2.5-10 (particulate matter less than 10 µm and greater than 2.5 µm in aerodynamic diameter). Long-term measurements of PM2.5 and PM2.5-10 were compared with the all-cause, cardiovascular, and respiratory mortality observed from January 2006 till December 2012 in three large cities in Korea (viz., Seoul, Busan, and Incheon). A time-series analysis based on a quasi-Poisson distribution was used to evaluate the associations of PM2.5 and PM2.5-10 with mortality. A 10 µg m−3 increase in PM2.5 (lag01) was associated with an increase of 1.18% (95% CI: 0.64, 1.72), 0.34% (95% CI: 0.03, 0.64), and 0.43% (90% CI: 0.02, 0.95) in the all-cause mortality in Busan, Seoul, and Incheon, respectively, during the study period. An increase in respiratory mortality of 0.52% (95% CI: 0.09, 0.96) and 2.25% (95% CI: 0.38, 4.15) was associated with a 10 µg m–3 increase in PM2.5 (lag01) in Seoul and Busan, respectively. Overall, the strongest associations were observed in Busan as well as among the elderly population. Statistically significant associations between ambient PM2.5 and PM2.5-10, and mortality were observed in this study. Exposure to fine particles, which mostly originate in combustion and mobile emissions, showed stronger effects on human health than coarse particles, which mostly originate in natural sources such as soil and mechanical processes.

Air quality simulation of existing city block using chemistry-coupled CFD model

In urban area, roadside air pollution is a serious environmental issue. In order to evaluate the roadside air pollution, it is requires to consider the both of chemical reaction and shape of buildings. In this study, a chemistry-coupled CFD (computational fluid dynamics) model was applied to assess the roadside air quality in a real situation. CBM-IV (Carbon bond mechanism IV) was used as the chemical reaction model coupled to the CFD model. The performance of the chemistry-coupled CFD model was tested in Umeda-shindo (Osaka prefecture), where roadside monitoring station is located, 24 hours on 23rd August 2010. The boundary conditions were calculated by air quality model WRF-CMAQ (Weather Research and Forecasting - Community Multiscale Air Quality Modeling System). Results showed that comparing with the observation data, the chemistry-coupled CFD results showed better accuracy in NOx concentration than the WRF-CMAQ data. In a real situation, the building geometry and mobile emission were found to have great impacts on the urban air quality in the CFD simulation, emphasizing the importance to assess the roadside air pollution with high spatial resolution.

Environmental safety management of urban building by regulation of formation process of exhaust gases of motor vehicles

Modern development of the construction industry involves accounting and assessment of operating conditions of structures. Excessive technological environmental impact can lead to economic losses and a decrease in the efficiency of investment projects in construction. Mobile sources emission record is an important component of the ecosystem state diagnosis in modern cities. For scientifically substantiated and reliable determination of the mass flow of the motor vehicles pollutants it is necessary to take into account the mixture formation and combustion of the working mixture in the internal combustion engine. The article describes the authors' approach to calculating the volumetric flow rate of exhaust gases based on the characteristics of the vehicle's transport operations available for operational control. Studies have shown that, when using a particular fuel, the determination of the volume flow rate of exhaust gases can be reduced to finding the power of the engine . In addition, the composition changes of the fuel (or fuel replacement) and the regulation of the effective power of the engine (by organization of traffic) allow to influence on the volume and composition of the emission of exhaust gases of vehicles and on the pollution of the urban environment in general. The results of the studies make it easier to calculate the mass of pollutant emissions by the transport stream into the outer air and can be used as preliminary data to assess the negative anthropogenic impact on the ecosystem.

Assessment of car emission masses at the change of kinetic energy of the “engine – transport vehicle” system

Negative anthropogenic impact on the environment can lead to global changes in the natural cycle of substances in the biosphere and the climate change in general. Assessment of the mobile sources emission is an important component of the diagnosis of the urbanized landscapes ecosystem state. The effective power of the car engine is accepted as the characteristic unambiguously reflecting the movement of the vehicle. The algorithm of determination of pollutants emission masses is stated in the article and unique calculation of relative effective power of the engine is presented. The current value of the engine effective power taking into account transformation of variable parameters to the coded sizes depending on kinematic and dynamic factors is calculated from the equation of the car movement at the change of kinetic energy of the “engine - transport vehicle” system in the form of Lagrange. Such dynamic characteristics as coefficient of the rotating masses and coefficient of mechanical efficiency of transmission are presented by functions of the engine relative effective power. Results of the research considerably simplify calculation of pollutants emission masses by traffic flow into the atmosphere and can be used for assessment of negative anthropogenic impact on the ecosystem.

Emission factors of black carbon and co-pollutants from diesel vehicles in Mexico City

Abstract. Diesel-powered vehicles are intensively used in urban areas for transporting goods and people but can substantially contribute to high emissions of black carbon (BC), organic carbon (OC), and other gaseous pollutants. Strategies aimed at controlling mobile emissions sources thus have the potential to improve air quality and help mitigate the impacts of air pollutants on climate, ecosystems, and human health. However, in developing countries there are limited data on the BC and OC emission characteristics of diesel-powered vehicles, and thus there are large uncertainties in the estimation of the emission contributions from these sources. We measured BC, OC, and other inorganic components of fine particulate matter (PM), as well as carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), ethane, acetylene, benzene, toluene, and C2-benzenes under real-world driving conditions for 20 diesel-powered vehicles encompassing multiple emission level technologies in Mexico City with the chasing technique using the Aerodyne mobile laboratory. Average BC emission factors ranged from 0.41–2.48 g kg−1 of fuel depending on vehicle type. The vehicles were also simultaneously measured using the cross-road remote sensing technique to obtain the emission factors of nitrogen oxide (NO), CO, total hydrocarbons, and fine PM, thus allowing for the intercomparison of the results from the two techniques. There is overall good agreement between the two techniques and both can identify high and low emitters, but substantial differences were found in some of the vehicles, probably due to the ability of the chasing technique to capture a larger diversity of driving conditions in comparison to the remote sensing technique. A comparison of the results with the US EPA MOVES2014b model showed that the model underestimates CO, OC, and selected VOC species, whereas there is better agreement for NOx and BC. Larger OC / BC ratios were found in comparison to ratios measured in California using the same technique, further demonstrating the need for using locally obtained diesel-powered vehicle emission factor database in developing countries in order to reduce the uncertainty in the emissions estimates and to improve the evaluation of the effectiveness of emissions reduction measures.

Shielding Efficiency of a Fabric Based on Amorphous Glass-Covered Magnetic Microwires to Radiation Emitted by a Mobile Phone in 2G and 3G Communication Technologies

Abstract A dual band mobile phone model was used to check the shielding properties of an amorphous ferromagnetic textile against the radiation emitted by the handset. Two frequencies belonging to the 2nd and 3rd generation of mobile emission technologies were used, 897 MHz and 1950 MHz. The specific absorption rate (SAR) of energy deposition in a human head phantom was measured in standardized conditions. The textile contained micrometric-diameter wires of a ferromagnetic mixture embedded in a thin glass coat and weaved in a specific way. A set of fabric orientations and configurations (layering) were provided in the experiment in order to achieve a better shielding to the phone’s radiation. Compared with the non-shielded handset, SAR deposited in the head while using the fabric-covered phone could be decreased up to 30 % of its initial value – in case of 2G technology and up to 24 % – in case of 3G technology. This type of material shows one of the highest shielding efficiencies of the electric-field component in near-field exposure conditions reported until now. A cubic curve of SAR decrease in depth of the head was revealed in both uncovered and covered handset, the effect of shielding being larger at the higher frequency.

BASF invests in third plant for specialty zeolites used for the production of mobile emissions catalysts

BASF invests in third plant for specialty zeolites used for the production of mobile emissions catalysts

Evaluating commercial marine emissions and their role in air quality policy using observations and the CMAQ model

We investigate the representation of emissions from the largest (Class 3) commercial marine vessels (c3 Marine) within the Community Multiscale Air Quality (CMAQ) model. In present emissions inventories developed by the United States Environmental Protection Agency (EPA), c3 Marine emissions are divided into off-shore and near-shore files. Off-shore c3 Marine emissions are vertically distributed within the atmospheric column, reflecting stack-height and plume rise. Near-shore c3 Marine emissions, located close to the US shoreline, are erroneously assumed to occur only at the surface. We adjust the near-shore c3 Marine emissions inventory by vertically distributing these emissions to be consistent with the off-shore c3 Marine inventory. Additionally, we remove near-shore c3 Marine emissions that overlap with off-shore c3 Marine emissions within the EPA files.The CMAQ model generally overestimates surface ozone (O3) compared to Air Quality System (AQS) site observations, with the largest discrepancies occurring near coastal waterways. We compare modeled O3 from two CMAQ simulations for June, July, and August (JJA) 2011 to surface O3 observations from AQS sites to examine the efficacy of the c3 Marine emissions improvements. Model results at AQS sites show average maximum 8-hr surface O3 decreases up to ∼6.5 ppb along the Chesapeake Bay, and increases ∼3–4 ppb around Long Island Sound, when the adjusted c3 Marine emissions are used.Along with the c3 Marine emissions adjustments, we reduce on-road mobile NOX emissions by 50%, motivated by work from Anderson et al. 2014, and reduce the lifetime of the alkyl nitrate species group from ∼10 days to ∼1 day based on work by Canty et al. 2015, to develop the “c3 Science” model scenario. Simulations with these adjustments further improve model representation of the atmosphere. We calculate the ratio of column formaldehyde (HCHO) and tropospheric column nitrogen dioxide (NO2) using observations from the Ozone Monitoring Instrument and CMAQ model output to investigate the photochemical O3 production regime (VOC or NOX-limited) of the observed and modeled atmosphere. Compared to the baseline, the c3 Science model scenario more closely simulates the HCHO/NO2 ratio calculated from OMI data.Model simulations for JJA 2018 using the c3 Science scenario show a reduction of surface O3 by as much as ∼13 ppb for areas around the Chesapeake Bay and ∼2–3 ppb at locations in NY and CT downwind of New York City. These reductions are larger in 2018 than in 2011 due to a change in the photochemical O3 production regime in the Long Island Sound region and the projected decline of other (non-c3 Marine) sources of O3 precursors, highlighting the importance of proper representation of c3 Marine emissions in future modeling scenarios.

Environmental degradation, ICT and inclusive development in Sub-Saharan Africa

This study examines how information and communication technology (ICT) complements carbon dioxide (CO2) emissions to influence inclusive human development in forty-four Sub-Saharan African countries for the period 2000–2012. ICT is measured with internet penetration and mobile phone penetration. The empirical evidence is based on Generalised Method of Moments. The findings broadly show that ICT can be employed to dampen the potentially negative effect of environmental pollution on human development. We establish that: (i) ICT complements CO2 emissions from liquid fuel consumption to increase inclusive development; (ii) ICT interacts with CO2 intensity to negatively affect inclusive human development and (iii) the net effect on inclusive human development is positive from the complementarity between mobile phones and CO2 emissions per capita. Conversely, we also establish evidence of net negative effects. Fortunately, the corresponding ICT thresholds at which these net negative effects can be completely dampened are within policy range, notably: 50 (per 100 people) mobile phone penetration for CO2 emissions from liquid fuel consumption and CO2 intensity. Theoretical and policy implications are discussed.