Due to the high energy cost of city living, NYC metropolitan area faces many challenges when it comes to maintaining clean air. Every day New Yorkers come into contact with fuel combustion from transportation, heating oil, Electric power generators and various other pollutants. One of the challenges of cleaning up NYC's air is the fact that New York has the highest density of fine particulates (soot pollution) than any other city in America. More than half of these pollutants originate from sources outside of the city, hindering efforts towards cleaner air in NYC. PlaNYC was first launched in 2007 with the goal of achieving the cleanest air standards of any city in United States by 2030. To fulfill this ambitious goal, the City's strategy is to find cost effective ways to reduce pollution, pursue natural solutions to improve quality and, finally, to measure ground level air pollution systematically. A portion of the PlaNYC strategy is reducing on-road pollution. Today, NYC has the greenest municipal fleet in the nation, 95% of which is equipped with an emission reduction device, and all of which use ultra-low sulfur diesel fuel, and at least 5% biodiesel blend. These vehicles have already shown dramatically reduced emissions and fuel costs. To further address the issue of vehicle pollution, the City Council passed Local Law 61 in 2009, requiring all school buses to be retrofitted with cabin air pollution filters and lowered the retirement age for the older buses. This enabled the Department of Education to take the oldest buses off city streets. Law 61 also requires that the replacement buses comply with the EPA emission standards. NYC also developed initiatives to equip public and private ferries with cleaner engines and pollution control equipment. The Staten Island Ferry has already undergone significant upgrades and engine retrofits - its ferries are fueled by Ultra Low Sulfur Diesel (ULSD). To better understand the scope of NYC's air pollution issue, the Department of Health and Mental Hygiene launched the New York City Community Air Survey (NYCCAS) in December 2008. It measured the variations in street-level air pollutants in more than 100 locations throughout the city using low cost modular air quality monitoring units. From the data collected, it was concluded that there was a significant impact to the air quality in neighborhoods were many of the buildings utilized heavy oil. On average these neighborhoods had 30 percent higher levels of fine particulate matter (PM2.5) in air than other neighborhoods. To combat this issue, the city has partnered with Environmental Defense Fund to launch the NYC Clean Heat Program, and has since been working on reducing PM 2.5 emissions from heavy oil by 50 %. In 2013, NYC is already half way to this goal, with 35% reduction in PM 2.5 emission. Buildings significantly contribute to air pollution in NYC. Residual heating oil (no.4 and no.6) is the dirtiest fuel permitted to heat buildings and is used more in NYC than anywhere else. These residual oils are made of low-quality end products of the oil refining process and are primarily used to power ships and heavy machinery. In NYC, many condominiums, apartment complexes and large commercial buildings use these fuels for heating, because they are relatively cheap. Unfortunately, what make these fuels cheap are its many impurities, which cause inefficient combustion and unhealthy black emissions. This is a significant concern, because boiler emissions are not regulated, and as a result they are responsible for 14 percent emissions of PM 2.5 into the city air. The NYC Community Air Survey winter monitoring also indicated that in densely populated areas the levels of SO2 were 150 percent higher, owing to a high concentration of residual oil burning units. Many of the city's high income neighborhoods suffer from some of the city's worst street level air pollution. Over 9,000 buildings in the city produce disproportionately high emissions by burning the highly polluting residual oil. In addition, high concentrations of metals like nickel in residual oil emissions produce the type of PM 2.5 which is particularly harmful. To reduce pollution, the city launched the initiative to replace boilers in many public schools with clean, efficient fuel systems. To maximize health benefits the city decided to start conversions in neighborhoods with the highest asthma rates. By 2017, the City will modify the boiler systems in 100 of 478 public schools. The replacement of old, dirty boilers with new, clean and fuel efficient models will lead to a 50 percent reduction in CO2and a 44 percent reduction in soot emissions at these locations. Today NYC government enforces law 194-A which mandates lower sulfur content in no.4 and no. 6 heating oils and minimum 2% biodiesel fuel requirement in all heating oil used in the city. The City also pursues natural solutions to improve air quality. The Department of Parks and Recreation has launched the Trees for Public Health (TPH) initiative, and identified six neighborhoods as its prime targets. These neighborhoods - Far Rockaway, East Harlem, Morrisania, East New York, Stapleton and Hunts Point - were selected because they have fewer than average street trees and higher than average rates of asthma among young people. Trees in these neighborhoods will reduce pollutants that trigger respiratory disorders. The goal is to completely green these neighborhoods with new trees on both public and private land. Since the launch of the initiative, East Harlem, Far Rockaway, Stapleton and Morrisania have been fully stocked with trees.