(a) Scientific studies have found an association between exposure to particulate matter and significant human health problems, including: aggravated asthma; chronic bronchitis; reduced lung function; irregular heartbeat; heart attack; and premature death in people with heart or lung disease. Exposure to air pollutants that are carcinogens has significant human health consequences as well. For example, exposure to diesel exhaust is an established cause of lung cancer.
(b) One in three Americans has heart or blood vessel disease; heart disease and stroke are the first and fourth leading causes of death in the U.S., respectively. Air pollution affects heart health and can trigger heart attacks and strokes. Exposure to air pollutants contributes to most of the leading causes of death for San Franciscans: ischemic heart disease; lung, bronchus and tracheal cancers; cerebrovascular disease; chronic obstructive pulmonary disease; hypertensive heart disease and lower respiratory infection. Short-term effects of exposure to air pollution include constriction or chest tightening that causes discomfort or limits normal activity and that makes exercise difficult. And long-term changes in lung function may include lung tissue inflammation, leading to chronic lung disease.
(c) Persons living in close proximity to air pollution sources, such as freeways or busy roadways, have poorer lung functions and are more susceptible to develop asthma and other respiratory problems, compared with persons living at a greater distance from sources. The California Air Resources Board's 2005 Land Use Guidance document, Air Quality and Land Use Handbook: A Community Health Perspective, reviewed traffic-related air pollution studies and found that particulate matter pollution levels decrease by about 70 percent at 500 feet from freeways and high-traffic roadways, defined as urban roads with 100,000 vehicles/day or rural roads with 50,000 vehicles/day.
(d) Proximity to sources of air pollution increases exposure and proximity to sources is more common for the poor and for certain ethnic minorities.
(e) Consequently, health vulnerability varies among neighborhoods and populations within San Francisco, as measured by population health records of air pollution-associated hospital discharges and emergency room visits, and non-accident mortality. Health vulnerable populations are likely to have more significant health consequences from air pollutant exposure compared to populations that are less vulnerable.
(f) Construction activities can be a significant source of diesel exhaust emissions. When such emissions are not controlled, they can become a nuisance and public health risk.
(g) According to the California Air Resources Board off-road equipment, which includes construction equipment, is the sixth largest source of diesel particulate matter emissions in California.
(h) The City and County of San Francisco ("the City") has an interest in protecting public health by reducing diesel exhaust emissions from publicly funded construction sites.
(i) The City can reduce exhaust emissions from off-road diesel equipment by requiring City contractors on public works projects within an Air Pollutant Exposure Zone, as defined in the Health Code, to use equipment with lower exhaust emissions and to reduce exhaust emissions through a construction emissions minimization plan.
(j) The use of newer technologies, such as verified diesel emission control strategies, combined with newer engines (Tier 2 or later), can reduce particulate matter emissions from construction equipment between 89 and 94 percent compared to older, dirtier equipment.
(k) It is feasible to require City contractors to use these newer technologies and newer engines in limited areas within San Francisco based on the wide availability of newer technologies and the availability of newer engines across all sizes of fleets, equipment types, and sizes of engines, as shown by California Air Resources Board inventories. Furthermore, both the state and federal governments have adopted regulations, such as the California Air Resources Board's In-Use Off-Road Diesel Vehicle Regulation, that will require newer, cleaner equipment as the useful life of older engines expires and the engines become obsolete.
(l) The City can further reduce the exposure to diesel emissions from off-road diesel equipment by creating and implementing bidding incentives for City contractors to utilize the cleanest possible off-road diesel equipment on public works projects.
(m) The City can also reduce the exposure to diesel emissions from off-road diesel vehicle fleets by seeking funding to retrofit City owned equipment and other off-road diesel equipment operated in the City. Existing funding sources include incentive programs such as the Carl Moyer Air Quality Standards Attainment Program.
(n) By adopting this Chapter 25, the City intends to exercise its power to make economic decisions involving its own funds as a participant in the marketplace and to conduct its own business as a municipal corporation to ensure that purchases and expenditures of public monies are made in a manner consistent with clean construction practices.
(o) Nothing in this Chapter 25 shall be interpreted or applied so as to create any power or duty in conflict with any federal or state law.