Health Risk Assessment Posed by the Mobile Source Air Toxics on an Urban to Regional Area

Air toxics are important health concern. The purpose of this research was to develop a protocol to predict exposure concentrations of air toxics and inhalation cancer and noncancer risk that come from different gasoline and diesel-fueled sources. The protocol was developed by linking the U.S. EPA’s Models-3/CMAQ model as the exposure model and toxicological and epidemiological evidence functions. The NEI version 3 for the year 1999 was used in this analysis for point, area, and non-road sources, whereas NMIM was used to create the on-road emissions. The year 2003 was used for meteorological data and as reference to compare the monitored concentrations to model performance. The modeling domain consisted of a 36 km domain. To demonstrate the system’s effectiveness, this study was performed on priority mobile sources air toxics (1, 3-butadiene, benzene, formaldehyde, acetaldehyde, acrolein, and DPM), and was applied to Nashville, Tennessee using available air toxics monitored data. Ten emissions scenarios were selected in this study to compare the main results. This research on air toxics emission scenarios was based on relative analyses and estimates of absolute exposure concentrations and health risk values. The proposed protocol was demonstrated and can be used for decision makers in the quantitative assessment of new policies that will affect the public health and the air quality by air toxics. Eliminating emission source categories is clearly not a policy option, but rather helps gain a better understanding of the total magnitude of the health effects associated with these major sources of air toxics, principally of DPM. Higher formaldehyde and acetaldehyde exposure concentrations occurred in the summer season, while benzene and 1,3-butadiene occurred in winter. DPM did not show a strong seasonality exposure during the year 2003 in Nashville. DPM generated the higher lifetime cancer risk excess among the other air toxics in Nashville, posing a cancer risk that was 4.2 times higher than the combined total cancer risk from all other air toxics. Those high cancer risk levels were due mainly to non-road sources (57.9%). For the on-road diesel fueled sources (DFS), the principal reductions were due to the DPM contributions generated by HDDVs rather than LDDVs. An evident positive synergism in the cancer risk reduction occurred when reducing diesel on-road and non-road source emissions simultaneously. The main cancer risk reductions from acetaldehyde, benzene, 1,3-butadiene, and formaldehyde (4HAPs) were due to the contribution of biogenic sources with 32.2%. This condition was followed for the scenario that did not consider on-road sources with a 27.5% of reduction. For non-road sources, the main reductions were due to the air toxics contributions generated by gasoline LDVs, principally benzene and 1,3-butadiene. The scenario 2020 showed a DPM and 4HAPs health effect reductions of approximately 32.8 and 19.4 %, respectively in Nashville. Higher cancer and non-cancer risks occurred on Southeastern urban areas due to long-term exposure to DPM, principally in Atlanta, GA, followed by Nashville, TN, Birmingham, AL, Raleigh, NC, and Memphis, TN. This research provided strong evidence that reducing ambient DPM concentrations will lead to improvement in human health more than other air toxics in Nashville, indicating that better technologies and regulations must be applied to mobile diesel engines, principally, over non-road diesel sources

Health risk assessment posed by primary diesel particulate matter and vapor air toxics in Southeastern US

Air toxics concentrations and health effects that come from different sources emission scenarios by linking Models-3/CMAQ and cancer risk assessment were predicted. The year 1999 was used to emissions inventory and the year 2003 for meteorological data and modeling performance. To demonstrate the system's effectiveness, this study was performed on priority mobile sources air toxics; benzene, 1,3-butadiene, formaldehyde, acetaldehyde, and diesel particulate matter (DPM). The analysis was applied mainly to Nashville in the Southeastern US. Ten emissions scenarios were selected to compare the principal results. DPM posed a cancer risk that was 4.2 times higher than the combined total cancer risk from all other four air toxics. Those high cancer risk levels were due mainly to non-road sources (57.9%). For the on-road diesel fueled sources, the principal reductions were due to the DPM generated by heavy duty diesel vehicles. The main on-road reductions were due to the air toxics generated by gasoline light duty vehicles, principally benzene and 1,3-butadiene. Reducing ambient DPM concentrations would lead to improvement in human health more than other air toxics, indicating that better technologies and regulations must be applied to the mobile diesel engines, principally, over non-road diesel sources. This is an abstract of a paper presented at the AWMA's 99th Annual Conference and Exhibition (New Orleans, LA 6/20-23/2006)

Modeling and source apportionment of diesel particulate matter

The fine and ultra fine sizes of diesel particulate matter (DPM) are of greatest health concern. The composition of these primary and secondary fine and ultra fine particles is principally elemental carbon (EC) with adsorbed organic compounds, sulfate, nitrate, ammonia, metals, and other trace elements. The purpose of this study was to use an advanced air quality modeling technique to predict and analyze the emissions and the primary and secondary aerosols concentrations that come from diesel-fueled sources (DFS). The National Emissions Inventory for 1999 and a severe southeast ozone episode that occurred between August and September 1999 were used as reference. Five urban areas and one rural area in the Southeastern US were selected to compare the main results. For urban emissions, results showed that DFS contributed (77.9% ± 8.0) of EC, (16.8% ± 8.2) of organic aerosols, (14.3% ± 6.2) of nitrate, and (8.3% ± 6.6) of sulfate during the selected episodes. For the rural site, these contributions were lower. The highest DFS contribution on EC emissions was allocated in Memphis, due mainly to diesel non-road sources (60.9%). For ambient concentrations, DFS contributed (69.5% ± 6.5) of EC and (10.8% ± 2.4) of primary anthropogenic organic aerosols, where the highest DFS contributions on EC were allocated in Nashville and Memphis on that episode. The DFS contributed (8.3% ± 1.2) of the total ambient PM2.5 at the analyzed sites. The maximum primary DPM concentration occurred in Atlanta (1.44 μg/m3), which was 3.8 times higher than that from the rural site. Non-linearity issues were encountered and recommendations were made for further research. The results indicated significant geographic variability in the EC contribution from DFS, and the main DPM sources in the Southeastern U.S. were the non-road DFS. The results of this work will be helpful in addressing policy issues targeted at designing control strategies on DFS in the Southeastern U.S

Generation and Dispersion Model of Gaseous Emissions from Sanitary Landfills

A mathematical model was developed to quantify the environmental impact produced by the gases emission from sanitary landfills. The stages of gas generation and diffusion were modeled using waste and cover materials placed in a landfill over an isotropic porous medium, while the dispersion stage was modeled for the atmosphere using a Gaussian model. The United States Environmental Protection Agency (USEPA) criteria were adopted for the estimation of greenhouse gases emissions. The MATLAB computer program was used to prepare simulations of a proposed sanitary landfill to serve the municipalities of Temuco and Padre Las Casas in Chile, considering a lifetime of 20 years. The simulated results show that the conditions of confinement have a greater incidence on the rate of gas emission than does the quantity of waste disposed. It was also concluded that the level of environmental impact varies considerably according to the evaluation scenario and the project design

Emission Scenarios and the Health Risks Posed by Priority Mobile Air Toxics in an Urban to Regional Area: An Application in Nashville, Tennessee

Toxic air pollutants, also known as hazardous air pollutants, are those that are known or suspected to cause cancer or other serious health effects, such as birth defects or adverse environmental outcomes. The aim of this research was to predict air toxics related health risks due to different emission scenarios by linking Models-3/CMAQ and cancer risk assessments. To demonstrate the effectiveness of this approach, this study was performed on the priority mobile source air toxics (PMSAT) of benzene, 1,3-butadiene, formaldehyde, acetaldehyde, and diesel particulate matter (DPM), based on data from 2003. The analysis was carried out in the eastern US, and mainly in Nashville, TN. Ten emissions scenarios were examined, including a 2020 scenario with the effects of on-road mobile source regulations. The results show that DPM poses a cancer risk that is 4.2 times higher than the combined total cancer risk from all of four other PMSAT. These high cancer risk levels are mainly due to non-road sources (57.9%). The main cancer risk from acetaldehyde, benzene, formaldehyde, and 1,3-butadiene (4HAPs) is due to biogenic sources, which account for 32.2% of this risk, although these cannot be controlled. Excluding DPM, the main on-road cancer risk contribution was due to the air toxics generated by gasoline light duty vehicles (LDVs), principally benzene and 1,3-butadiene. The scenario for 2020 showed reductions in the adverse health effects related to DPM and 4HAPs of 32.8 and 19.4%, respectively. This research provides strong evidence that reducing ambient DPM concentrations will lead to greater improvements in human health than other air toxics, indicating that better technologies and regulations must be applied to mobile diesel engines, as these have more significant adverse health effects than non-road diesel sources

A hybrid ARIMA and artificial neural networks model to forecast particulate matter in urban areas: The case of Temuco, Chile

Air quality time series consists of complex linear and non-linear patterns and are difficult to forecast. Box-Jenkins Time Series (ARIMA) and multilinear regression (MLR) models have been applied to air quality forecasting in urban areas, but they have limited accuracy owing to their inability to predict extreme events. Artificial neural networks (ANN) can recognize non-linear patterns that include extremes. A novel hybrid model combining ARIMA and ANN to improve forecast accuracy for an area with limited air quality and meteorological data was applied to Temuco, Chile, where residential wood burning is a major pollution source during cold winters, using surface meteorological and PM10 measurements. Experimental results indicated that the hybrid model can be an effective tool to improve the PM10 forecasting accuracy obtained by either of the models used separately, and compared with a deterministic MLR. The hybrid model was able to capture 100% and 80% of alert and pre-emergency episodes, respectively. This approach demonstrates the potential to be applied to air quality forecasting in other cities and countries

The effect of switching mobile sources to natural gas on the ozone in the great smoky mountains national park

Mobile sources are among the largest contributors of NOx in the Great Smoky Mountains National Park region (GSMNP). In 2001, these sources contributed 45% of NOx emissions. From 1990 to 2001, the growth of vehicle miles traveled (VMT) increased 60% and 55% in neighboring Sevier and Blount counties respectively. These emissions combined with the high volatile organic compounds (VOC) emissions in the Southeast area have caused the ozone ground level concentration to be as high as some major metropolitan areas in the summer season. In 2001, the maximum 8-hr ozone concentration inside the park was 103 parts per billion. In response to high ozone levels in other areas, federal, state, and local governments are promoting the use of alternative, clean, and reformulated fuel vehicles as a means to improve local air pollution. One of these fuels is compressed natural gas (CNG). The purpose of this project was to use USEPA's CMAQ system in order to model the air quality and compare the ozone ground level formation in the GSMNP from light duty vehicles (LDVs) operating with 100% CNG within 100 miles around GSMNP. A severe southeast ozone episode between August and September 1999 was used as a reference and 2004 was used as a future case. Results showed that LDVs fueled with 100% CNG in the domain could reduce ozone level by 10% and 8% for 1-hr and 8-hr ozone formation respectively in the GSMNP on the modeled time period. Scavenging occurred around the GSMNP in the morning time during the selected episode

Particulate air pollution and health effects for cardiovascular and respiratory causes over an industrial neighborhood; Linking epidemiological time series studies and the power of a health perception survey

Talcahuano and Hualpén counties are one of the most highly industrial-polluted coastal zones in Chile, overhanging the iron foundry industry, coal burning power plants, chemical industry, and petroleum refinery, etc. The relationship between air pollution from PM2.5 measured at the Libertad monitoring station and health effects as the daily number of deaths and hospital admissions, for specific cardiovascular and respiratory diseases were studied. The results were compared with a health perception survey applied to the local population during spring 2008. Significant statistical associations were found between daily mortality and morbidity in Talcahuano-Hualpén area for cardiovascular and respiratory diseases and daily PM2.5 concentration, coinciding with the health perception of the inhabitants from these counties. The results suggest that point sources may be responsible for increased mortality in that industrial area. This has an important implication in relation with the size and chemical composition of the particles, but also for monitoring and control strategies. This is an abstract of a paper presented at the 103rd AWMA Annual Conference and Exhibition (Alberta, Canada 6/22-25/2010)

Particulate air pollution and health effects for cardiovascular and respiratory causes in Temuco, Chile: A wood-smoke-polluted urban area

Temuco is one of the most highly wood-smoke-polluted cities in the world. Its population in 2004 was 340,000 inhabitants with 1587 annual deaths, of which 24% were due to cardiovascular and 11% to respiratory causes. For hospital admissions, cardiovascular diseases represented 6% and respiratory diseases 13%. Emergency room visits for acute respiratory infections represented 28%. The objective of the study presented here was to determine the relationship between air pollution from particulate matter less than or equal to 10 μm in aerodynamic diameter (PM10; mostly PM2.5, or particulate matter <2.5 μm in aerodynamic diameter) and health effects measured as the daily number of deaths, hospital admissions, and emergency room visits for cardiovascular, respiratory, and acute respiratory infection (ARI) diseases. The Air Pollution Health Effects European Approach (APHEA2) protocol was followed, and a multivariate Poisson regression model was fitted, controlling for trend, seasonality, and confounders for Temuco during 1998-2006. The results show that PM10 had a significant association with daily mortality and morbidity, with the elderly (population >65 yr of age) being the group that presented the greatest risk. The relative risk for respiratory causes, with an increase of 100 μg/m3 of PM10, was 1.163 with a 95% confidence interval (CI) of 1.057-1.279 for mortality, 1.137 (CI 1.096-1.178) for hospital admissions, and 1.162 for ARI (CI 1.144-1.181). There is evidence in Temuco of positive relationships between ambient particulate levels and mortality, hospital admissions, and ARI for cardiovascular and respiratory diseases. These results are consistent with those of comparable studies in other similar cities where wood smoke is the most important air pollution problem. Copyright 2009 Air & Waste Management Association