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HomeMy WebLinkAboutAudience Comments 1 r2. /z ,Cr ,Jcheb ce (ty 6 - Dear Renton City Council Members, I would like to express concerns about the Renton Municipal Airport Master Plan. I attended the January 15th Master Plan Open House with the idea that the public would be able to provide input and express concerns with the plan. Unfortunately I found the opportunity to do so very limited. Since the Airport is property of the City of Renton I would like to express my concerns directly to you. I live under the flight path of the airport and have had airport officials tell me that the City should never have allowed residential development in these areas the only problem with that argument is that my house predates the airport by 20 some years. My biggest airport concern has to do the "Pleasure Craft". The larger aircraft have made significant improvement in noise reduction and fuel consumption over the years. Currently the number of take offs for large aircraft from the airport is in my opinion manageable and there has been an effort to restrict take off times so that there is minimal impact on surrounding neighborhoods. I do have concerns about how changes in the Master Plan may affect these practices. "Pleasure Craft", on the other hand, have not undergone the same level of improvements. There has been no significant reduction in noise generated by these aircrafts and they continue to use leaded fuel, a fuel that has been banned in most every other application. I distinctly remember a conversation I had with a City of Renton official 30+years ago who stated at the time that the Renton Airport was the most lead contaminated airport in the State of Washington. I don't know if that is true I have asked the question to airport staff and was told that no one knows of any lead study at the airport. I did a quick Google search concerning lead contamination at airports and found numerous articles and have attached four for your reading (1 I VfN G NEAR SMAIA, AIRPORTS INCREASES ASE 111D P I,_iI FI( RISK, A Geospatial Analysis of the Effects of Aviation Gasoline on Childhood Blood Lead Levels FAA Fact Sheet-Leaded Aviation Fuel and the Environment, California Center for Environmental Health's ground-breaking legal agreement on Aviation Fuel) Lead is a well know contaminate and very stringent regulations have been passed to reduce exposure. I have even heard of people having problems getting their houses painted because of lead concerns but yet we allow"Pleasure Craft"to fly over our heads spewing lead exhaust to rain down on our gardens, yards and homes. Not only that, where does the lead go? Does it just keep accumulating, year after year and if so when does it reach a toxic level? According to the FAA Fact Sheet"All forms of lead are toxic." I understand that airport issues are very complex but I do know one thing and that is if I were generating as much noise as a "Pleasure Craft" on my property the City of Renton would be all over me to reduce the noise. For my protection the City/State imposes very strict regulations concerning my use of lead in fuels and paints but as a resident who is a neighbor to the airport I am expected to endure the very things that I am regulated against. It seems like a very one sided arrangement to me. What is the most bothersome to me is that I see absolutely no incentive placed on "Pleasure Crafts"to make improvements like those made by larger aircraft.Instead we tell neighboring residents to just suck it up. I find it hard to believe that the City has no control over the airport after all why own something you have no control over? I am not opposed to change but I do believe that the driver behind change should be to make the City a better place, after all what is the point of any of this if it is not to make a better City. There must be some creative ways that the City can influence positive change whether by regulating the type of fuel that is sold,fees that are charge, permits required,there must be something. For in my mind it is clear, it has already been proven with the larger aircraft that with the right incentives tremendous positive change can occur with the way that aircraft affect the environment. After all if it's not the City who is interested in lobbying for the health and safety of its residence than who is? Thank You Jeff Dineen 320 Smithers Ave S Renton Wa 98057 CEH Center for environmental Health Map: California Neighborhoods Affected by Lead from Aviation Fuel If you live near an airport, either a small regional airport or a large airport that is also used by small planes,you know that air quality problems are a daily reality. Lead pollution from small airplanes that continue to use lead-based fuel is a major problem, since lead can adversely affect the nervous system, kidney function, immune system, reproductive and developmental systems and the cardiovascular system. CEH took legal action in California to address the pollution problem from lead-based aviation fuel, and we have reached a ground-breaking legal agreement to help alleviate lead pollution around 23 California airports. We also expect our legal action will prompt the aviation industry to adopt lead-free fuel more quickly, sparing the air around airports nationwide. If you live near a small airport that is not on our list, contact CEH (caroline(&eeh.org)for more information. You can also sign up for our mailing list to stay informed on this, and also receive many other health tips for your children and families. Leaded Gas: Out of Cars But Still in Planes If you were driving a car before 1995, you may remember that cars sometimes used"regular"(leaded gasoline). Leaded gasoline was the only gasoline available between the 1920s and the early 1970s. Between 1974 and 1995, the use of leaded gas for cars was gradually phased out. The US Environmental Protection Agency called this "one of the one of the great environmental achievements of all time," noting that "thousands of tons of lead have been removed from the air, and blood levels of lead in our children are down 70 percent. This means that millions of children will be spared the painful consequences of lead poisoning, such as permanent nerve damage, anemia or mental retardation." While cars were required to use unleaded fuel after 1995, today small propeller planes(often called general aviation planes)and some helicopters are still allowed to use leaded aviation gas(avgas). Currently, leaded avgas is the largest source of lead air pollution in the US,causing emissions of over 500 tons of lead per year. Recent research has found that children living near general aviation airports have higher blood lead levels than children living farther away, and studies have linked high childhood lead levels to a host of serious health problems. 4"',, ., Federal Aviation - Administration ,_,,,, Fact Sheet - Leaded Aviation Fuel and the Environment (www.faa.aovinews/stay connected!) For Immediate Release June 19, 2013 Contact: Henry J. Price Phone: (202) 267-3883 Aircraft operating on leaded aviation gasoline (avgas) are used for many critical purposes, including business and personal travel, instructional flying, aerial surveys, agriculture, firefighting, law enforcement, medical emergencies, and express freight. What is avgas? Avgas is a specialized fuel used to power piston engine aircraft. Aviation gasoline is a complex mixture of relatively volatile substances known as hydrocarbons that vary widely in their physical and chemical properties. The properties of avgas must be properly balanced to give reliable and safe engine performance over an extremely wide range of aircraft operating conditions. Manufacturers typically certify their engines and aircraft to run on fuels that meet American Society of Testing Materials (ASTM) Standards, or other consensus standards such as the United Kingdom's Defense Standards, or U.S. Military Standards, which govern the chemical, physical and performance properties of avgas. The various grades of avgas are identified using the Motor Octane Number(MON) combined with the following alpha-designations to indicate lead content: low lead (LL); very low lead (VLL); or unleaded (UL). Although there are various ASTM Standards for avgas, almost all avgas on the U.S. market today is low lead, 100 MON avgas (100LL). This grade of avgas satisfies the requirements of all piston engines using avgas, regardless of their performance level. Jet aircraft and turbine-powered, propeller aircraft do not use avgas, but instead use fuels very similar to kerosene, which does not contain a lead additive. Why is octane so important? Octane is a measure of the performance of a fuel as it bums in an engine combustion chamber. It is a measure of a gasoline's ability to resist detonation, or "knock". Octane is important to the safe operation of an aircraft or automobile engine. High compression, high displacement engines, such as those found in many high performance, piston engine aircraft, require high octane fuels so that detonation,which is the uncontrolled ignition of the fuel in the combustion chamber, does not damage pistons and other engine components and result in engine failure. High performance engines allow an aircraft to operate at increased speeds and with more payload, but these engines require higher octane avgas. Operating aircraft or automotive piston engines on fuels with lower octane than they require may result in damage from knock, but it is generally safe to operate piston engines on fuels of a higher octane rating than their minimum requirement. In other words, it is safe to go up in octane, but not down. What is Tetraethyl Lead (TEL)? TEL is an organic compound that contains lead and, in small quantities, is very effective in boosting octane. The ban of TEL in automobile gas was phased in over a number of years and was largely completed by 1986 and resulted in significant reductions of lead emissions to the environment. TEL was has not yet been banned for use in avgas, because no operationally safe alternative is currently available. Is TEL Toxic? All forms of lead are toxic if inhaled or ingested. Lead can affect human health in several ways, including effects on the nervous system, red blood cells and cardiovascular and immune systems. Infants and young children are especially sensitive to even low levels of lead,which may contribute to behavioral and learning problems and lower IQ. Children have increased sensitivity due to their developing nervous systems. How are aircraft emissions regulated? Under the Clean Air Act(CAA), the EPA has the authority (in consultation with the FAA) to regulate emissions from aircraft. The CAA specifies that, in setting standards, the agencies must consider the time needed to develop required technology, consider cost, and must not adversely impact aircraft safety or noise. At present,there are no regulations that apply to emissions from aircraft that use leaded fuel. However, FAA enforces existing emission standards for commercial jet aircraft and engines through the certification process of engines. Commercial jet engine manufacturers have responded to requirements for emissions reductions through technology changes by improving jet engine designs and efficiency. If the EPA finds that aircraft emissions present an endangerment to public health or welfare, they can establish limits on aircraft emissions, and then the FAA has the authority to regulate aircraft emissions through the development of standards for the composition or chemical or physical properties of an aircraft fuel or fuel additive. Why keep using leaded fuel? First and foremost, the use of leaded fuels is an operational safety issue, because without the additive TEL, the octane levels would be too low for some engines, and use of a lower octane fuel than required could lead to engine failure. As a result, the additive TEL has not been banned from avgas. Aircraft manufacturers, the petroleum industry, and the FAA have worked for over a decade to find alternative fuels that meet the octane requirements of the piston engine aircraft fleet without the additive TEL. However, no operationally safe, suitable replacement for leaded fuel has yet been found to meet the needs of all of the piston engine aircraft fleet. What is FAA doing about eliminating leaded aviation fuels? Four initiatives have been established to develop a safe unleaded replacement aviation gasoline: First and most important, the FAA sponsored an Aviation Rulemaking Committee (ARC) involving EPA and industry stakeholders, which developed the process, cost estimate, and time line to replace existing leaded aviation fuels with unleaded solutions. The final report and recommendations, known as the Unleaded Avgas Transition (UAT) Committee Final Report was published on February 17, 2012. The report is available to the public at: www.faa.gov/about/initiatives/avgas/archive. This report contains five key recommendations (and fourteen additional recommendations) to facilitate the development and deployment of a replacement unleaded aviation gasoline. The plan calls for government research and development(R&D)funding and in-kind funding from industry to identify an unleaded fuel by 2018 that could be used by aircraft currently operating on leaded avgas. Second, the FAA has established an Agency performance metric that states: "A replacement fuel for leaded aviation gasoline is available by 2018 that is usable by most general aviation aircraft." This performance metric will guide investments and decisions taken on by FAA for the coming years. To help meet this goal, the FAA asked the world's fuel producers on June 10 to submit proposals for fuel options that would help the general aviation industry make a transition to an unleaded fuel. The FAA will assess the viability of candidate fuels in terms of their impact on the existing fleet, their production and distribution infrastructure, their impact on the environment and toxicology, and economic considerations. The FAA is asking fuel producers to submit by July 1, 2014, data packages for candidate replacement unleaded fuel formulations for evaluation by the FAA. By Sept. 1, 2014, the FAA will select up to 10 suppliers to participate in phase one laboratory testing at the FAA's William J. Hughes Technical Center. The FAA will select as many as two fuels from phase one for phase two engine and aircraft testing. That testing will generate standardized qualification and certification data for candidate fuels, along with property and performance data. Over the next five years, the FAA will ask fuel producers to submit 100 gallons of fuel for phase one testing and 10,000 gallons of fuel for phase two testing. There are approximately 167,000 aircraft in the United States and a total of 230,000 worldwide that rely on 100 low lead avgas for safe operation. It is the only remaining transportation fuel in the United States that contains the addition of TEL. Third, Section 910 of the 2012 FAA Modernization and Reform Act establishes an unleaded aviation gasoline R&D program with deliverable requirements for an R&D plan and report. The FAA has issued the Unleaded Avgas Transition (UAT)Action Plan that will integrate these three activities. The fourth initiative involves private-sector companies that have applied for Supplemental Type Certificates for specific piston engine and aircraft models to operate with new, unleaded aviation gasoline formulations. The FAA is actively working to support all of these initiatives. What is FAA doing in the short-term to reduce lead emissions from airports? FAA's goal for an unleaded avgas by 2018 is the long term solution that will, ultimately, allow for the elimination of lead emissions from aircraft that use leaded fuel. Until such fuels can be brought to market, there are actions that FAA can coordinate with airport and aircraft owners and operators to investigate options to reduce lead emissions at airports. Some of the measures that are being considered include: 1. Lower leaded fuel options: It may be possible for airports to supply lower leaded fuels in current fuel distribution systems. These fuels that meet ASTM standards have been approved for use in aircraft certified for their use and would be completely transparent in its distribution and use. Potential reductions in lead emissions are as much as 19 percent since these lower level fuels have approximately 19 percent less lead content than current fuels. 2. Consider unleaded automotive fuels as an option at airports: Approximately 40 percent of piston engine aircraft are either approved or eligible to obtain approval to operate on automotive fuels. This unleaded fuel could represent an option for some airports, however, any fuel used in aircraft engines must not contain ethanol; this requirement may limit the applicability of automotive fuels. This would require separate fuel systems and procedures to ensure that aircraft are fueled properly. Airport sponsors would have to make the necessary arrangements for supply, storage and distribution systems—with due consideration of the level of demand for two different fuel types—all of which may make this option challenging both logistically and financially. 3. Safely change aircraft operations to avoid concentrated lead emissions: Locations for engine run-up areas could be distributed over a wider area within an airport to reduce the potential for concentrated levels of lead emissions. It may also be possible to shorten taxi routes to lessen emissions. Such measures would be airport-specific and would have to consider operational safety as the highest priority. 4. Install vapor recovery systems: Vapor recovery systems, similar to those found at automotive filling stations, could be installed in bulk fuel delivery systems to minimize the release of avgas vapors which contain small concentrations of lead. 1144 This page was originally published at:https://www.faa.gov/news/fact sheets/news_story.cfm?newsld=14754 e • Environmental Health Perspectives Environ Health Perspect. 2011 Oct; 119(10): 1513-1516. Published online 2011 Jul 13. doi: 10.1289/ehp.1003231 PMCID: PMC3230438 PM I D: 21749964 Research A Geospatial Analysis of the Effects of Aviation Gasoline on Childhood Blood Lead Levels Marie Lynn Miranda,N Rebecca Anthopolos,and Douglas Hastings Author information Article notes Copyright and License information Disclaimer Children's Environmental Health Initiative, Nicholas School of the Environment, Duke University, Durham, North Carolina, USA iCorresponding author. Address correspondence to M.L. Miranda, Nicholas School of the Environment, Duke University, Box 90328, Levine Science Research Center Room A134, Durham, NC 27708 USA.Telephone: (919) 613- 8023. Fax: (919)684-3227. E-mail:adnarimm@ekud.ude Received 2010 Nov 19;Accepted 2011 Jul 13. Copyright notice Publication of EHP lies in the public domain and is therefore without copyright.All text from EHP may be reprinted freely. Use of materials published in EHP should be acknowledged (for example, ?Reproduced with permission from Environmental Health Perspectives?); pertinent reference information should be provided for the article from which the material was reproduced.Articles from EHP, especially the News section, may contain photographs or illustrations copyrighted by other commercial organizations or individuals that may not be used without obtaining prior approval from the holder of the copyright. This article has been cited by other articles in PMC. Go to: Abstract Background:Aviation gasoline,commonly referred to as avgas, is a leaded fuel used in small aircraft. Recent concern about the effects of lead emissions from planes has motivated the U.S. Environmental Protection to consider regulating leaded avgas. Objective: In this study we investigated the relationship between lead from avgas and blood lead levels in children living in six counties in North Carolina. Methods:We used geographic information systems to approximate areas surrounding airports in which lead from avgas may be present in elevated concentrations in air and may also be deposited to soil. We then used regression analysis to examine the relationship between residential proximity to airports and North Carolina blood lead surveillance data in children 9 months to 7 years of age while controlling for factors including age of housing,socioeconomic characteristics, and seasonality. Results: Our results suggest that children living within 500 m of an airport at which planes use leaded avgas have higher blood lead levels than other children.This apparent effect of avgas on blood lead levels was evident also among children living within 1,000 m of airports.The estimated effect on blood lead levels exhibited a monotonically decreasing dose—response pattern,with the largest impact on children living within 500 m. Conclusions:We estimated a significant association between potential exposure to lead emissions from avgas and blood lead levels in children.Although the estimated increase was not especially large,the results of this study are nonetheless directly relevant to the policy debate surrounding the regulation of leaded avgas. Keywords:avgas,aviation gasoline, blood lead,childhood,geospatial, lead poisoning Lead poisoning in children living in the United States has declined dramatically over the last several decades as a result of banning leaded gasoline, lead-based paint, and lead solder in plumbing. Nevertheless,children in the United States continue to be exposed to lead.The 2007-2008 National Health and Nutrition Examination Survey survey found blood lead levels at or above the Centers for Disease Control and Prevention (CDC) blood lead action level of 10 µg/dL in about 1.1%of 1-to 5-year- olds,or about 270,000 children (National Center for Health Statistics 2010). Even more worrisome is a large body of recent research that demonstrates negative health effects, including learning disabilities and behavioral disorders,associated with lead exposure levels well below the CDC action level (Canfield et al. 2003; Chiodo et al. 2004; Lanphear et al. 2000;Schnaas et al. 2006).A study by Miranda et al. (2007, 2009, 2010)suggests that early childhood blood lead levels as low as 2 µg/dL can have significant impacts on academic performance as measured by end-of-grade test scores. In response to this body of research,the CDC has stated that there is no safe level for blood lead in children (CDC 2005). One source of lead exposure that is often overlooked is aviation fuel. Lead emitted from aircraft using leaded aviation gasoline(avgas) is currently the largest source of lead in air in the United States, constituting about 50%of lead emissions in the 2005 National Emissions Inventory[U.S. Environmental Protection Agency(EPA) 2010].Although leaded gasoline for automobiles was phased out of use in the United States by 1995, lead is still permitted in avgas. Lead is added to avgas to achieve the high octane required for the engines of piston-driven airplanes.The most commonly used fuel for piston-driven aircraft in the United States is known as Avgas 100LL.Although the"LL"stands for low lead, 100LL gasoline contains up to 0.56 g/L lead (Royal Dutch Shell 2010).Another grade of avgas,Avgas 100, contains higher amounts of lead and is still in widespread use. Newer varieties of avgas without lead, including 82 UL and 94 UL, have been introduced recently.These unleaded fuels are not used as commonly as the two leaded grades, however, because their octane ratings are too low for many small aircraft engines. Previous research indicates that lead levels in air near airports where planes use avgas are significantly higher than background levels.A study at the Santa Monica airport in California found that the highest lead levels occur close to airport runways and decrease exponentially with distance from an airport, dropping to background levels at about 1 km (U.S. EPA 2010).Another study at Toronto-Buttonville (Canada)airport found that the average air lead level near the airport was 4.2 times higher than the background air lead level in Toronto over a 24-hr period (Environment Canada 2000),and a study at Chicago(IL)O'Hare airport found that air lead levels were significantly higher downwind from the airport than upwind (Illinois Environmental Protection Agency 2002). Thus,the combustion of leaded avgas by small airplane engines may pose a health risk to children who live or attend school near airports.The lead in air surrounding airports can be inhaled directly,or the lead may be ingested by children after it settles into soil or dust(U.S. EPA 2010).The U.S. EPA estimates that people living within 1 km of airports are at risk of being exposed to lead from avgas (Hitchings 2010).The U.S. EPA further notes that about 16 million people live within 1 km of an airport with planes using avgas,and 3 million children attend school within 1 km of these airports (U.S. EPA 2010). Because of the risk of lead poisoning from avgas, environmental groups have pressured the U.S. EPA to take action to reduce lead emissions from aviation fuel. One environmental group, Friends of the Earth, has petitioned the U.S. EPA to find endangerment from and regulate lead in avgas.The U.S. EPA has responded with an Advanced Notice for Proposed Rulemaking on aviation fuel and solicited comments and further research about the effects of lead in avgas away(U.S. EPA 2010).The U.S. EPA has refrained from establishing a date by which aircraft would be required to use unleaded fuel [AOPA(Aircraft Owners and Pilots Association) ePublishing staff 2010]. Here we seek to contribute to research regarding the risk of lead in avgas by determining whether living near airports where avgas is used has a discernible impact on blood lead levels in children. Previous studies have examined whether lead from avgas is present in air and soil near airports. Our work seeks to link avgas exposure to childhood blood lead levels.To elucidate the effects of avgas on blood lead levels,we compared blood lead levels in children living near airports in six counties in North Carolina with those in children living farther away from airports but residing in the same counties. We used a multiple regression model to control for other variables that have previously been found to affect blood lead levels(CDC 1991, 1997;Sargent et al. 1995) in an effort to isolate the impact of avgas.The results of this study are directly relevant to the policy debate surrounding the regulation of leaded avgas. Go to: Methods We obtained a database of airports in North Carolina from the U.S. EPA Office of Transportation and Air Quality(2008).The database contained estimates for the annual lead emissions from each airport,along with the spatial location of each facility. We used ArcGIS 9.3(ESRI, Redlands,WA)to plot the locations of these airports against a county boundary map of North Carolina.We selected six counties in North Carolina (Carteret, Cumberland,Guilford, Mecklenburg, Union,and Wake) (Figure 1). Counties were selected based on whether they contained multiple airports with significant air traffic,where significant numbers of children had been screened for lead exposure,and where the county tax assessor data would allow us to control for age of housing as an important confounder when assessing avgas as a source of lead exposure(Table 1). Because we wanted to control for risk from deteriorating lead-based paint,we selected counties where the county tax assessor data contained a well-populated field for age of housing. We obtained North Carolina blood lead surveillance data for all children in the study counties between the ages of 9 months and 7 years who had been tested for lead between 1995 and 2003 from the Children's Environmental Health Branch within the North Carolina Department of Environment and Natural Resources(North Carolina Childhood Lead Poisoning Prevention Program 2004). Because we were unable to ascertain where the children attended school,we were not able to control for the location of their school relative to the airports. Most of the children screened for lead are not yet old enough to be attending school.All aspects of this study were conducted in accordance with a human subjects research protocol approved by the institutional review board (IRB)of Duke University. GUI t+rrwa, CtiIrt*(artt Open in a separate window Figure 1 Study counties. Table 1 Number of airports,estimate of lead emissions from aircrafts,and number of blood lead screens among children 9 months to 7 years of age in study counties, North Carolina (1995-2003). No.of Estimated lead emissions No.of blood lead County airports (tons/year) screens Carteret 8 0.224 3,333 Cumberland 11 0.238 14,854 Guilford 10 0.369 27,043 Mecklenburg 10 0.894 47,510 Union 14 0.285 3,387 Wake 13 0.624 29,070 Open in a separate window After selecting our six study counties, we used geographic information systems(GIS)to delineate fixed distance areas around each airport where aircraft use avgas.We also used GIS to connect the point locations of the airports given by address to tax parcel layers for each county via shared geography.The tax parcel layers contain a polygon shape representing the property boundary of each airport.We then created buffers around each of the airport polygons to represent the area in which airplane emissions could affect air lead levels. Because previous research has indicated that lead concentrations increase exponentially with proximity to airports (Piazza 1999),we created buffers that extended 500 m, 1,000 m, 1,500 m,and 2,000 m from the polygon edges of the airport tax parcels. Figure 2 depicts this approach using the example of Wake County.Airports are indicated by the darkest shade of pink, with the different distance buffers represented by increasingly lighter shades of pink.The residential addresses of the children who were screened for blood lead is then overlaid,as shown by the green points. In accordance with our IRB protocol,the green dots do not represent the actual locations where children were screened for lead. For publicly displayed maps like Figure 2,we randomly move the actual location of the child within a fixed radial buffer, a technique known as jittering.The analysis itself, however, is done on the true locations of the children.The 500-m, 1,000-m, 1,500-m,and 2,000-m buffers only approximate the area that could be affected by lead emissions from airports,as wind directions can alter the dispersal pattern of lead particles. Nevertheless,with varied wind directions and planes that take off in multiple directions,our buffers offer a reasonable approximation of the area over which lead from avgas might disperse. 6ranvdle Nnicir Uwham _... .._.. ( �3 - JubnKon 'ti „d Open in a separate window Figure 2 Airports buffered at distances of 500 m, 1,000 m, 1,500 m,and 2,000 m in Wake County, North Carolina, plotted along with a jittered representation of the residential addresses of the children screened for blood lead. North Carolina maintains a mandatory statewide registry of blood lead surveillance data.We obtained North Carolina blood lead surveillance data for 1995-2003 (North Carolina Childhood Lead Poisoning Prevention Program 2004), because these years bracket the 2000 census data. In previous work designed to develop childhood lead exposure risk models (Kim et al. 2008; Miranda et al. 2002),we had already geocoded the residential addresses of children screened for lead. Our geocoding success rates ranged from 37 to 89%across the six study counties. Details on how the blood lead surveillance data were processed are described by Miranda et al. (2002) and Kim et al. (2008). We then joined the buffered airport polygons in our six study counties with the geocoded addresses of children who have been screened for blood lead.This enabled us to generate a table containing blood lead screening results and four dummy variables representing whether each child lived within 500 m, 1,000 m, 1,500 m, or 2,000 m of an airport. We supplemented the blood lead screening and airport location data with data from county tax assessor databases on age of housing(to control for lead exposure risks from deteriorating lead-based paint), resolved at the individual tax parcel level. In addition,we used U.S. Census 2000 data on household median income(measured in tens of thousands)and proportion receiving public assistance,which were obtained at the census block group level (U.S. Census Bureau 2002),as well as proportion non-Hispanic black and proportion Hispanic,which were obtained at the census block level (U.S.Census Bureau 2001). Because previous work has shown the season of blood lead screening to be a significant predictor of blood lead levels(i.e.,warm months are correlated with higher lead exposure from lead-based paint) (Johnson et al. 1996; Kim et al. 2008; Miranda et al.2007;Yiin et al. 2000),we created individual level dummy variables representing the season in which each child was screened for lead. Because the blood lead screening data are right-skewed, we used the natural logarithm of blood lead level in our analyses. We used the spatial data architecture described above to regress logged blood lead levels on the proximity to airport variable,controlling for age of housing,season in which the child was screened, and the census demographic variables. We used multivariable regression analysis clustered at the census block group level with inverse population weights at the tax parcel level to ensure that parcels with multiple blood lead screens did not overly influence the analysis.We implemented crude and adjusted regression models for each of the four proximity to airport variables.We used a categorical distance to airport variable with 0-500 m, 501-1,000 m, 1,001-1,500 m,and 1,501-2,000 m,with a reference group of>2,000 m. In addition,we performed a sensitivity analysis on our findings. First,we investigated whether the use of inverse population weights accounted for possible correlation among observations from the same tax parcel by running multilevel random intercept models designating the parcel as the grouping variable.Second,we considered the possibility of temporal confounding by including the lead screen year as a factor in each model with the reference year as 1995. Results regarding the importance of distance to airports were robust across these alternative specifications.We examined the results of these regressions to determine whether living near an airport using avgas had significant effects on blood lead levels.Statistical significance was set at a=0.05 Go to: Results Blood lead screening data were available for 125,197 children in the study counties(Table 1), including 13,478 children living within 2,000 m of an airport polygon in the six study counties (Table 2). Table 2 Individual and group-level characteristics of children 9 months to 7 years of age who were screened for blood lead 1995-2003(n = 125,197). Characteristic Value Individual level I Characteristic Value Blood lead level [pg/dL(mean ±SD)] 3.88±2.94 Season in which blood lead screening occurred [n (%)]a Winter 27,189(21.72) Spring 30,593(24.44) Summer 35,256(28.16) Fall 32,159(25.69) Residential proximity to airport [n (%)] Within 500 m 1,267 (1.01) Within 1,000 m 3,649(2.92) Within 1,500 m 8,122 (6.49) Within 2,000 m 13,478(10.77) >2,000 m 111,719(89.23) Year residence of child built(mean±SD) 1970±20.10 Group level (mean±SD) Proportion blackb 0.39±0.33 Proportion Hispanicb 0.09±0.15 Household median income($10,000s)c 4.38±2.09 Proportion receiving public assistancec 0.04±0.05 aWinter: December—February;spring: March—May;summer:June—August;fall:September—November. bResolved at the census block level.cResolved at the census block group level. Open in a separate window Our statistical results are shown in Table 3. In unadjusted models, logged blood lead levels were significantly and positively associated with residential proximity to an airport,with the size of the association being larger for children living closer to airports.Although controlling for individual-and group-level confounders attenuated the association between logged blood lead levels and residential proximity to an airport, evidence of a deleterious relationship remained. In the adjusted models,control variables behaved as expected: Relative to being screened in the winter season,children tested in the spring,summer,or fall had increased blood lead levels,on average. Residence in poor and minority neighborhoods was also associated with elevated lead levels. In contrast, recently constructed housing units were associated with decreased mean lead levels.The above associations were consistent between the within-distance and categorical distance regression models. Table 3 Change in logged blood lead level associated with a child's residential proximity to airport using multiple linear regression (n= 125,197). Within distance buffersa Categorical distance measure Coefficient(95% Covariate CI) Covariate Coefficient(95%CI) Unadjusted (0.038 to Within 500 m 0.089 (0.034 to 0.144)# Between 0 and 500 m 0.094 0.150)# Between 501 and (0.027 to Within 1,000 m 0.084 (0.036 to 0.133)# 0.085 1,000 m 0.142)# Between 1,001 and (0.023 to Within 1,500 m 0.077 (0.039 to 0.116)# 0.071 1,500 m 0.119)# Between 1,501 and (-0.022 to Within 2,000 m 0.052 (0.018 to 0.087)# 0.016 2,000 m 0.053) >2,000 m Reference Adjustedb (0.006 to (0.006 to Within 500 m 0.043 0.080)** Between 0 and 500 m 0.043 0.080)** Between 501 and (-0.003 to Within 1,000 m 0.037 (0.010 to 0.065)# 0.034 1000 m 0.072)* Within distance buffersa Categorical distance measure Coefficient(95% Covariate CI) Covariate Coefficient(95%CI) Within 1,500 m 0.021 (0.0008 to Between 1,001 and 0.007 (-0.020 to 0.041)** 1,500 m 0.034) Between 1,501 and (-0.041 to Within 2,000 m 0.003 (-0.013 to 0.020) —0.019 2,000 m 0.003)* >2,000 m Reference aWithin-distance thresholds were entered in separate regression models. bAdjusted models control for census block level proportion black and proportion Hispanic,census block group level percent population receiving public assistance and household median income,as well as individual level dummy variables for the season in which a child was screened for blood lead. *p<0.10. **p<0.05.#p<0.01. Open in a separate window In the within-distance buffer specification for the adjusted models, blood lead levels were significantly associated with residing within 500 m [coefficient=0.043;95%confidence interval (CI),0.006-0.080]; 1,000 m (coefficient=0.037;95%CI,0.010-0.065),and 1,500 m (coefficient=0.021;95%CI,0.0008- 0.041)of an airport. Blood lead levels were not associated with living at greater distances. Importantly, the magnitude of the coefficient on the distance to airport variables was largest for those children living within 500 m and decreased in a dose—response fashion out to 1,500 m. On the basis of distance to airport coefficients,children living within 500 m, 1,000 m,or 1,500 m of an airport had average blood lead levels that were 4.4, 3.8,or 2.1%higher, respectively,than other children. In the categorical distance specification,compared with the reference category(>2,000 m from an airport),children living within 500 m of an airport had blood lead levels that were,on average,4.4% higher(coefficient=0.043;95%CI,0.006-0.080) (Table 3). In addition,the coefficient for the 501-1000 m category was marginally significant(coefficient=0.034;95%CI,—0.003 to 0.072). Neither the 1,001- 1,500 m nor the 1,501-2,000 m category was significant at the 5%level,with coefficient estimates near the null value.These results taken collectively suggest that children living within 500 m and within 1,000 m are driving the results in the models that entered the within-distance threshold variables separately. Go to: Discussion Based on the geospatial and statistical analysis presented above, lead from avgas may have a small (2.1- 4.4%) but significant impact on blood lead levels in children who live in proximity to airports where avgas is used.The magnitude of the estimated effect of living near airports was largest for those children living within 500 m and decreased in a monotonic fashion out to 1,500 m. Because our model takes into account only whether a child is living anywhere in a fixed distance(500 m, 1,000 m, or 1,500 m) radius of an airport, children who live very close to or downwind from a runway could be affected more significantly than the average value that we estimate for all children living within the buffer. Our finding that living beyond 1,000 m of an airport using avgas does not have a significant relationship with blood lead levels is reasonably consistent with previous research suggesting that lead drops to background levels beyond 1,000 m from an airport(Piazza 1999). Our study has several important limitations. It does not take into account wind patterns that could increase the extent of the area containing lead particles from avgas in certain directions and decrease it in others. Furthermore,our model considers only whether children live anywhere within a particular distance from an airport and does not consider the fact that some points within this area could have higher air lead concentrations than others.Our modeling of the relationship between avgas and blood lead could be improved by incorporating wind direction information,by obtaining information about where piston-engine aircraft typically take off or land at each airport, and by controlling for air traffic volume. In addition,the variability in our geocoding success rates may introduce spatial bias.To partially address this,we re-ran the analysis without Union County,which had the lowest geocoding rate(37% compared with 58%for the remaining counties combined).The distance from airport results were robust to this change in the data set.We also note that if one includes a rural county like Union County, geocoding rates are inevitably poor.We felt it important to include a rural county, so we reported results with Union County data. Nonetheless,the analysis presented here would be strengthened with better geocoding rates. Finally,extending the study to additional counties throughout the United States could increase sample size and determine whether the trends that we observed in North Carolina are replicated elsewhere in the country.The methods we describe here for constructing buffer zones around airports could easily be replicated in other areas nationally(or internationally). Go to: Conclusions Our analysis indicates that living within 1,000 m of an airport where avgas is used may have a significant effect on blood lead levels in children.Our results further suggest that the impacts of avgas are highest among those children living closest to the airport.This study adds to the literature examining whether leaded avgas poses risks to children's health and speaks directly to the ongoing policy debate regarding the regulation of leaded avgas. %,0 � y ENVIRONMENTAL ..... POLLUTION CENTERS VI 111 uttO I t T ',I ;NIW"SrS SOIL .AIR$ts l ER MOD €'" %I!O HOME 1 AIR 1 LIVING NEAR SMALL AIRPORTS INCREASES LEAD POLLUTION RISK LIVING NEAR SMALL AIRPORTS INCREASES LEAD POLLUTION RISK March 30,2017 8189 users 0 Category:Air share on tacebook share on twitter share on•oo.lc+ 4-0010 Many of us may find living close to airports undesirable. This is mostly because of the inevitable noise and traffic implications. Some of us may also suspect that airport traffic could also generate unwelcome air pollution. However, few of us may be aware that small airports could generate some additional and potentially serious specific risk as compared to large international ones. The main implication is that pollution generated by the activity of small airports may end up affecting more people. While few residences are located close(e.g.,within a mile or less)to big commercial airports,small airports are typically located in more densely populated areas. This news article aims to inform you on some recent research and associated concerns related to areas around small airports. Recent Research Revealed that the Heavy Metal Lead (Pb) Is Still Present in Aviation Gasoline Used in Small Aircraft Lead (Pb) is a heavy metal known for its toxicity to human beings(particularly to children) and the environment. It can adversely affect the nervous system, immune system, and kidney function, as well as interfere with the reproductive and developmental systems and the cardiovascular system. Lead?s well-established toxicity is the reason for its ban from leaded gasoline used in cars from several decades now. However, recent research (http:/Iwww.ceh.org/avgas/) revealed that Pb is still present in aviation gasoline used on small propeller planes and some helicopters in levels that are high enough to potentially cause air pollution risks.