Richard William Baldauf

United States Environmental Protection Agency | US EPA · Office of Research and Development

Urban air quality stands as a pressing concern in cities globally, with airborne particulate matter (PM) emerging as a significant threat to human health. An investigation was carried out to examine the potential of four prevalent evergreen roadside tree species grown at different locations in Dhaka to capture PM using their leaves. The distributio...

Green-blue-grey infrastructure (GBGI) offers environmental benefits in urban areas, yet its impact on air pollution is under-researched, and the literature fragmented. This review evaluates quantitative studies on GBGI's capability to mitigate air pollution, compares their specific pollutant removal processes, and identifies areas for further inves...

Communities located in near-road environments experience elevated levels of traffic-related air pollution. Near-road air pollution is a major public health concern, and an environmental justice issue. Roadside green infrastructure such...

As a Nature-Based Solution, roadside green infrastructure (also known as roadside barriers) can potentially mitigate traffic-related air pollution by increasing dispersion and promoting pollutant deposition. For new and existing roadside barriers, the vegetation’s physical and ecological attributes (dimensions and density) are dynamic in nature, an...

The role of school location in children’s air pollution exposure and ability to actively commute is a growing policy issue. Well-documented health impacts associated with near-roadway exposures have led school districts to consider school sites in cleaner air quality environments requiring school bus transportation. We analyze children’s traffic-re...

Many countries have adopted portable emissions measurement system (PEMS) testing in their latest regulations to measure real-world vehicular emissions. However, its fleetwide implementation is severely limited by the high equipment costs and lengthy setup procedures, posing a need to develop more cost-effective, efficient emission measurement metho...

Trees in urban areas have a significant impact on air quality and other environmental issues. Trees can affect the concentration of air pollutants that we breathe in by directly removing pollutants or avoiding emissions and secondary pollutant formation in the atmosphere. In addition, trees have other benefits including increasing property value, i...

Communities located in near-road environments face adverse health effects due to elevated exposures to traffic-related air pollution (TRAP). While the use of a combination of solid structures (i.e. sound walls) and vegetation barriers can be an effective TRAP mitigation tool, installing these barriers can also present challenges to local communitie...

Free viewing link. available for free till March 28, 2020! https://authors.elsevier.com/c/1aWu7B8cco9K1 With increasing population, rapid urbanization, and increased migration to cities, the local impacts of increasing transportation and industrial-related air pollution are of growing concern worldwide. Elevated air pollution concentrations near...

Spatially and temporally resolved air quality characterization is critical for community-scale exposure studies and for developing future air quality mitigation strategies. Monitoring-based assessments can characterize local air quality when enough monitors are deployed. However, modeling plays a vital role in furthering the understanding of the re...

Emissions from transportation sources can impact local air quality and contribute to adverse health effects. The Kansas City Transportation and Local-Scale Air Quality Study (KC-TRAQS), conducted over a 1-year period, researched emissions source characterization in the Argentine, Turner, and Armourdale, Kansas (KS) neighborhoods and the broader sou...

Green infrastructure (GI) in urban areas may be adopted as a passive control system to reduce air pollutant concentrations. However, current dispersion models offer limited modelling options to evaluate its impact on ambient pollutant concentrations. The scope of this review revolves around the following question: how can GI be considered in readil...

Roadside vegetation has been shown to impact downwind, near-road air quality, with some studies identifying reductions in air pollution concentrations and others indicating increases in pollutant levels when vegetation is present. These widely contradictory results have resulted in confusion regarding the capability of vegetative barriers to mitiga...

Freight transport has been shown to impact air quality at the local and regional scale. Health studies indicate that exposure to diesel exhaust can result in adverse health effects. In addition, other studies indicate that populations spending significant amounts of time near busy roads, often supporting freight transport, also face increased risks...

Air pollution from mobile sources has been identified by numerous organizations as a public health concern. With increasing traffic on major interstates, an increasing number of people are at risk of exposures to high levels of near-road air pollution. Fixed and mobile air quality sensors offer advantages to assessing these impacts. Studies demonst...

Nitrogen dioxide (NO2) not only is linked with adverse effects on the respiratory system, but also contributes to the formation of ground-level ozone (O3) and fine particulate matter (PM2.5). Our curbside monitoring data analysis in Detroit, MI and Atlanta, GA strongly suggests that a large fraction of NO2 is produced during the “tailpipe-to-road”...

Elevated air pollution levels adjacent to major highways are an ongoing topic of public health concern worldwide. Black carbon (BC), a component of particulate matter (PM) emitted by diesel and gasoline vehicles, was measured continuously via a filter-based light absorption technique over ~ 16 months at four different stations positioned on a perpe...

Intensifying the proportion of urban green infrastructure has been considered as one of the remedies for air pollution levels in cities, yet the impact of numerous vegetation types deployed in different built environments has to be fully synthesised and quantified. This review examined published literature on neighbourhood air quality modifications...

As public health concerns have increased due to the rising number of studies linking adverse health effects with exposures to traffic-related air pollution near large roadways, interest in methods to mitigate these exposures have also increased. Several studies have investigated the use of roadside features in reducing near-road air pollution conce...

Mobile monitoring is a strategy to characterize spatially and temporally variable air pollution in areas near sources. EPA's Geospatial Measurement of Air Pollution (GMAP) vehicle – an all-electric vehicle is outfitted with a number of measurement devices to record real-time concentrations of particulate matter and gaseous pollutants – was used to...

Traffic-related air pollution is a persistent concern especially in urban areas where populations live in close proximity to roadways. Innovative solutions are needed to minimize human exposure and the installation of vegetative barriers shows potential as a method to reduce near-road concentrations. This study investigates the impact of an existin...

Traffic emissions are associated with the elevation of health risks of people living close to highways. Roadside vegetation barriers have the potential of reducing these risks by decreasing near-road air pollution concentrations. However, while we understand the mechanisms that determine the mitigation caused by solid barriers, we still have questi...

In February 2015, the United States Environmental Protection Agency (EPA) sponsored a workshop in Research Triangle Park, NC, USA to review the current state of the science one missions, air quality impacts, and health effects associated with exposures to ultrafine particles[1].[...]

The black carbon (BC) emitted from heavy-duty diesel vehicles (HDDVs) is an important source of urban atmospheric pollution and creates strong climate-forcing impacts. The emission ratio of BC to total particle mass (PM) (i.e., BC/PM ratio) is an essential variable used to estimate total BC emissions from historical PM data; however, these ratios h...

Studies based on field measurements, wind tunnel experiments, and controlled tracer gas releases indicate that solid, roadside noise barriers can lead to reductions in downwind near-road air pollutant concentrations. A tracer gas study showed that a solid barrier reduced pollutant concentrations as much as 80% next to the barrier relative to an ope...

Numerous studies have shown that people living in near-roadway communities (within 100m of the road) are exposed to high ultrafine particle (UFP) number concentrations, which may be associated with adverse health effects. Vegetation barriers have been shown to affect pollutant transport via particle deposition to leaves and altering the dispersion...

Public health concerns regarding adverse health effects for populations spending significant amounts of time near high traffic roadways has increased substantially in recent years. Roadside features, including solid noise barriers, have been investigated as potential methods that can be implemented in a relatively short time period to reduce air po...

https://www.epa.gov/schools/best-practices-reducing-near-road-pollution-exposure-schools

Emissions of speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs), were measured in vehicle exhaust from three light-duty spark ignition vehicles operating on summer and winter grade gasoline (E0) and ethanol blended (E10 and E85) fuels. Vehicle testing was conducted using a three-phase LA92 driving cycle in a tem...

With increasing evidence that exposures to air pollution near large roadways increases risks of a number of adverse human health effects, identifying methods to reduce these exposures has become a public health priority. Roadside vegetation barriers have shown the potential to reduce near-road air pollution concentrations; however, the characterist...

Protecting the health of growing urban populations from air pollution remains a challenge for planners and requires detailed understanding of air flow and pollutant transport in the built environment. In recent years, the work undertaken on passive methods of reducing air pollution has been examined to address the question: “how can the built envir...

Unlabelled: Emissions tests were conducted on two medium heavy-duty diesel trucks equipped with a particulate filter (DPF), with one vehicle using a NOx absorber and the other a selective catalytic reduction (SCR) system for control of nitrogen oxides (NOx). Both vehicles were tested with two different fuels (ultra-low-sulfur diesel [ULSD] and bio...

Speciated volatile organic compounds (VOCs) were measured in diesel exhaust from three heavy-duty trucks equipped with modern aftertreatment technologies. Emissions testing was conducted on a chassis dynamometer at two ambient temperatures (-7 °C and 22 °C) operating on two fuels (ultra-low sulfur diesel and 20 % soy biodiesel blend) over three dri...

This paper presents an analysis of wind tunnel experiments of twelve different roadway configurations and modeling of these configurations using a Large-Eddy Simulation (LES) model, aiming at investigating how flow structures affect the impact of roadway features on near-road and on-road air quality. The presence of roadside barriers, elevated fill...

While air pollution control devices and programs are the primary method of reducing emissions, urban air pollution can be further mitigated through planning and design strategies, including vegetation preservation and planting, building design and development, installing roadside and near-source structures, and modifying surrounding terrain feature...

Unlabelled: Representative profiles for particulate matter particles less than or equal to 2.5 microm (PM2.5) are developed from the Kansas City Light-Duty Vehicle Emissions Study for use in the US. Environmental Protection Agency (EPA) vehicle emission model, the Motor Vehicle Emission Simulator (MOVES), and for inclusion in the EPA SPECIATE data...

Unlabelled: Exposures to mobile source air toxics (MSATs) have been associated with numerous adverse health effects. While thousands of air toxic compounds are emitted from mobile sources, members of a subset of compounds are considered high priority due to their significant contribution to cancer and noncancer health risks and the contribution of...

This study examines the chemical properties of carbonaceous aerosols emitted from three light-duty gasoline vehicles (LDVs) operating on gasoline (e0) and ethanol-gasoline fuel blends (e10 and e85). Vehicle road load simulations were performed on a chassis dynamometer using the three-phase LA-92 Unified Driving Cycle (UDC). Effects of LDV operating...

One proposed method for reducing exposure to mobile source air pollution is the construction or preservation of vegetation barriers between major roads and nearby populations. This study combined stationary and mobile monitoring approaches to determine the effects of an existing, mixed-species tree stand on near-road black carbon (BC) and particula...

Panama Canal Expansion Illustrates Need for Multimodal Near-Source Air Quality Assessment Gayle S. W. Hagler*†, Timothy M. Barzyk‡, Sue Kimbrough†, Vlad Isakov‡, Paul Gagliano§, Michelle S. Bergin∥, David D’Onofrio⊥, Richard W. Baldauf†#, and Chad R. Bailey# † U.S. Environmental Protection Agency, Office of Research & Development, National Risk Ma...

Unlabelled: A study, conducted in Las Vegas, NV from mid-December 2008 to mid-December 2009 along an interstate highway, collected continuous and integrated samples for a wide variety of air pollutant species including NO2 and NO(x) associated with roadway traffic. This study examined long-term trends of NO2 and NO(x) in a near-road environment co...

This report provides a summary of a field study conducted in Detroit, MI from September 29, 2010 thru June 20, 2011. The objective of this research study has been to determine MSAT concentrations and variations in concentrations as a function of distance from the highway and to establish relationships between MSAT concentrations as related to highw...

In 2010, the U.S. Environmental Protection Agency (EPA) promulgated new minimum monitoring requirements for the nitrogen dioxide (NO2) monitoring network in support of the revised 1-hour NO2 National Ambient Air Quality Standards (NAAQS). In the new monitoring requirements, state and local air monitoring agencies are required to install near-road N...

A thermal extraction-gas chromatography-mass spectrometry (TE-GC-MS) method was utilized to quantitatively examine semivolatile organic compounds (SVOCs) in fine particulate matter (PM2.5) collected from light-duty, gasoline-powered vehicle (LDGV) exhaust. Emissions were analyzed from a subset of 18 vehicles tested in the Kansas City Light-Duty Veh...

This research characterizes associations between multiple pollutants in the near-road environment attributed to a roadway line source. It also examines the use of a tracer gas as a surrogate of mobile source pollutants. Air samples were collected in summa canisters along a 300 m transect normal to a highway in Raleigh, North Carolina for five sampl...

Excess air pollution along roadways is an issue of public health concern to Federal, State, and local government environmental agencies and the public. This concern was the motivation for a long-term study to measure levels of air pollutants at various distances from a roadway in Las Vegas, Nevada. This study represents a joint effort between the U...

Roadside barriers, such as tree stands or noise barriers, are prevalent in many populated areas and have been shown to affect the dispersion of traffic emissions. If roadside noise barriers or tree stands are found to consistently lower ground-level air pollution concentrations in the near-road environment, this may be a practical strategy for redu...

The contribution of lubricating oil to particulate matter (PM) emissions representative of the in-use 2004 light-duty gasoline vehicles fleet is estimated from the Kansas City Light-Duty Vehicle Emissions Study (KCVES). PM emissions are apportioned to lubricating oil and gasoline using aerosol-phase chemical markers measured in PM samples obtained...

Report by EPA to the Federal Highway Administration pursuant to an interagency agreement (RW-69-922499) from June 1, 2007 to September 30, 2010. The study objective was to determine mobile source air toxics (MSAT) concentrations and variations in concentrations as a function of distance from the highway and to establish relationships between MSAT c...

Determination of the size-resolved elemental composition of near-highway particulate matter (PM) is important due to the health and environmental risks it poses. In the current study, twelve 24h PM samples were collected (in July-August 2006) using a low-pressure impactor positioned 20m from a Raleigh, North Carolina interstate. The interstate supp...

A multidisciplinary group of researchers and policy-makers met to discuss the state-of-the-science regarding the potential of roadside vegetation to mitigate near-road air quality impacts in April 2010. Scientists discussed several studies that have measured and modeled the impacts of vegetative barriers on near-road air quality. Workshop participa...

The EPA recently published monitoring requirements in support of the revision to the primary NO 2 NAAQS. As part of the rulemaking, certain state and local air agencies are required to operate near-road NO 2 monitors. The proposed methodology for state and local agencies to identify and install NO 2 near-road monitoring stations is presented. An up...

Emissions of gaseous and particulate contaminants from two flex-fuel and one non-flex-fueled light-duty vehicle operating on conventional gasoline (0% ethanol; EO), 10% ethanol gasoline (E10), and 85% ethanol gasoline (E85) were studied. Results showed the trends in vehicle emissions for these measured pollutants under the varying vehicle, fuel, an...

The issues associated with human exposure to traffic pollutants and near-road pollution issues are presented. Emissions from traffic contribute to pollutant concentrations at the local, urban, and regional levels and are the principal source of intra-urban variation in the concentrations of pollutants in many cities. The primary traffic patterns af...

Mobile sources significantly contribute to ambient concentrations of airborne particulate matter (PM). Source apportionment studies for PM10 (PM < or = 10 microm in aerodynamic diameter) and PM2.5 (PM < or = 2.5 microm in aerodynamic diameter) indicate that mobile sources can be responsible for over half of the ambient PM measured in an urban area....

We thank Muller et al. for their interest in our article (Cho et al. 2009) and concur that the secondary sizing of particulate samples initially collected with a size-selective cascade impactor and then resuspended in solution is useful information. In response to their comments, we prepared additional samples of the particulate matter (PM) in the...

EPA, in collaboration with FHWA, has been involved in a large-scale monitoring research study in an effort to characterize highway vehicle emissions in a near-road environment. The pollutants of interest include particulate matter with aerodynamic diameter less than 2.5 microns (PM2.5), mobile source air toxics (MSATs), black carbon, and regulated...

The National Near-Road Mobile Source Air Toxics Study was designed to evaluate short-term effects of traffic emissions and meteorology on air quality. Mobile source air toxics (MSAT) of interest to this project are 1,3-butadiene, benzene, acrolein, acetaldehyde and formaldehyde. Highly time resolved data on concentrations of MSAT and other mobile s...