According to the findings by the National Resource Defense Council (NRDC), dust, soot, and many particles in polluted air over the nation's 239 major cities cause 64,000 of premature heart and lungrelated deaths each year. In light of the new reports, the Environmental Protection Agency (EPA) has announced the plan to impose tougher restrictions to include fine particulate less than 2.5 microns (PM2.5). The new regulations could cost more than $2.5 billion a year to implement in a city like Chicago alone. Urban trees as a component of urban ecosystem can provide cost effective phyto-mitigation and phyto-remediation strategy for improving urban environment and quality of life. Previous studies have indicated that trees in Chicago removed 234 tons of particulate matter less than 10 microns (PM10) annually. To the extend that trees can control particulate pollution there is potential for improved air quality and substantial cost savings.