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TRANSCRIPT: DEARS video presentation NARRATOR: Carrying out its mission to protect the environment and safeguard human health, EPA must understand the risks posed by pollutants and other stressors. Exposure assessment is one critical input used by EPA and others to assess those risks. EPA’s National Exposure Research Laboratory (NERL) conducts research and development that leads to improved methods, measurements, and models to assess and predict exposures. The Detroit Exposure and Aerosol Research Study (DEARS) is an important step in NERL’s exposure research program. LINDA SHELDON, Associate Director for Health: “DEARS is a research study that really addresses some of the national ambient air quality standards. EPA bases its air regulations on the concept of protecting human health.” RON WILLIAMS, Team Leader, PM & Air Toxics Human Exposure Measurements: “It had six primary objectives to meet the needs of the NERL, and more importantly the needs of the Agency.” ALAN VETTE, Physical Scientist: “One of which was to understand the impact of specific source types on people’s exposure to air pollution. So, trying to get a better understanding of the impact of industrial point sources.” RON WILLIAMS: “Second, we wanted to understand what were the physical and chemical factors that influenced those relationships. Our third objective was understanding what were some of the human activity patterns and human activity factors that might influence those same relationships. Once we had established those three things, that would allow us go there and develop and improve models. We could go there and understand model data versus human exposure measured data. “Our fifth objective was to go there and perform source apportionment – or in other words, what were the sources affecting the community setting? What were the sources impacting the personal setting, or the indoor home environment? And, how do those relate to one another? That was our fifth objective. “Our sixth objective was understanding the relationship between particulate matter and criteria pollutant gases, like ozone, NO2, and SO2. By understanding these, we can look for surrogates of exposure and confounders that might influence human epidemiological studies. TIMOTHY WATKINS, Deputy Director, Human Exposure and Atmospheric Sciences Division: “The unique aspect about DEARS is the role of air toxics and the PM components, or the particular components of PM, that have not been investigated before.” LINDA SHELDON: “One of the big areas of uncertainty is what is the exposure, how do you estimate the exposure in the studies? DEARS was conducted to really determine what exposures were, and how we can estimate it in many areas of the country.” RON WILLIAMS: “Why did we choose Detroit? Well, Detroit is a very large metropolitan area and has a fairly large population base, but that was not the primary reason that the NERL decided to do its research there.” LINDA SHELDON: “First of all, there are a lot of different sources for air pollutants in Detroit, so it gave us the opportunity to study a number of different sources, the way they generate pollutants, how that affects the ambient air, and how it affects exposure.” ALAN VETTE: “At the time, Detroit was in non-attainment of the National Ambient Air Quality Standards. That was one consideration.” TIMOTHY WATKINS: “And because Detroit had some significant air quality issues, we thought we might be about to provide some important insights, particularly, as I said, to the relationship between ambient concentrations and exposures, and the role sources play in those relationships.” LINDA SHELDON: “In DEARS, we conducted several kinds of monitoring. First of all, the pollutants that we were concerned about were particulate matter, various organic compounds, and all of the different species of particulate matter. Where we monitored was in four different locations.” RON WILLIAMS: “One is personal-based. That’s the first one we were involved in. So to understand what people were exposed with on a personal basis, we have to go there and bring the monitors to the person, rather than the person to the monitors. How do we accomplish that? We place a vest on them. Our vests are nylon, very light-weight, that the person would wear over their existing clothing. And they would wear that vest at all times during the day, except when they were sleeping or changing clothes or bathing or other types of similar activities. “The second area that we wanted to look at was indoor measurements – residential indoor measurements. How did the person’s personal exposure compare to what was taking place indoors? Maybe there are indoor sources of exposure that we need to understand. We set up small monitoring stations inside every single home, making them child-proof and safe, and those monitors would be exactly the same as those that the person would wear, except they would be in what we’d call stationary mode – they wouldn’t be moving. We would place them in one place, a central location inside the house, and they would operate on the same time schedule as the personal monitoring, which in our case was approximately 9 a.m. to 9 a.m., every single day (for 24 hours).” ALAN VETTE: “We also did measurements outside of people’s homes. There were a number of people who were selected, or participated in the DEARS study, that lived in distinct neighborhoods in the Detroit area, and those areas were selected based on their relative proximity to different types of sources in the area.” TIMOTHY WATKINS: “We have ambient air quality monitoring systems that are set up at a central monitoring site that collects extensive information about air toxics concentrations and particulate matter concentrations.” LINDA SHELDON: “Now, the reason we did this is that in “epi” studies, the data that is usually most available are ambient monitoring site data, and that’s what people often use to estimate exposure. But what we wanted to determine was whether or not what you measure at the ambient site is actually what people breathe in the air that’s near them. And if it was, then that was fine – one could always use the ambient site. We did measurements at the other sites to be able to understand the relationships and the factors that could make a difference in going from the ambient site to what we actually breathe.” RON WILLIAMS: “The DEARS operated for three years in Detroit. U.S. EPA cannot do research studies like this in every city. We might not be able to do this in Chicago or St. Louis or Houston, but DEARS wasn’t designed to go there and be a one-time study. It was designed to go there and develop models and applications that could be applied to all Americans.” ALAN VETTE: “I think that ultimately gets back to the risk-assessment process that’s used for evaluation and review of air pollutant standards by EPA. That’s ultimately the impact that we’re trying to inform, is to provide additional information and useful information that can be used to provide better assessments of the standards — the National Ambient Air Quality Standards — so that they are more protective of public health.” TIMOTHY WATKINS: “The DEARS study will also provide tremendous opportunities to collaborate with health scientists to understand the role of air toxics and PM components in human health effects. There’s also extensive use of the DEARS data to develop modeling tools that can be used as input in epidemiological studies – for example, to investigate relationships between ambient air concentrations and asthma incidence in children.” RON WILLIAMS: “We also want to understand, what were the sources of exposure? As we said earlier, what you and I are exposed to really depends on where we are. Not just where we live, but what we do and how we spend our day. The source-apportionment models that we apply will help us understand what the true sources of exposure are, what their origins are, and how they might impact you and I, regardless of where we may live.” LINDA SHELDON: Exposure research really provides the models that allow us to predict what will happen, and what will happen in terms of global climate change, what will happen in terms of the regulations that EPA puts into place. We can do it not just in terms of what air pollution is, but how it’ll affect our water, how it’ll effect our land, how it affect our entire environment. So the idea that we can be more predictive in what we are doing becomes extremely, extremely important.”