Quantitative Forecasting & Spatial Assessment Tools
The San Francisco Department of Public Health has developed a number of tools to help quantitatively assess environmental and health impacts associated with land use development. These tools are described in more detail below.
Air Quality Measurement and Modeling (top)
Within an area or place, exposure to air pollution typically varies with higher levels of exposure proximate to sources of pollution. For example, motor vehicle air pollution emissions result in higher exposure for those living near freeways and busy roadways. Significant sources of intra-urban variation in air pollution also include truck routes, bus yards and distribution centers, commercial and industrial exhaust, topology, and the aspect ratio of urban canyons. Regional monitoring data conducted for national and state air quality standards does not assess the spatial variation in air pollution within cities nor does it identify air pollution “hot spots”.
SFDPH developed facility with air quality measurement and modeling tools to respond to the growing need to identify air quality hot spots within cities. SFDPH utilizes several tools to characterize air pollutant concentrations and hot spots within the City. Nitrogen dioxide passive dosimetry and particulate matter monitoring can characterize the relative concentrations of these pollutants using both short and long term samples; portable devices permit measurement within and among residences and at different points along a single street. Physical dispersion models use computer algorithms to predict the ambient concentrations of pollutants from roadway traffic and industrial sources taking into account meteorological conditions, pollutant type, traffic counts and types, and other parameters. Land use regression models characterize the spatial distribution of exposure in a city or region based on zoning, topology, traffic volume, prevailing meteorology, and other land use characteristics.
Environmental review of land use decisions has been the primary target for application of our air quality assessment tools. SFDPH has created air quality evaluation and mitigation guidance for evaluating health impacts associated with new residential development proposed near freeways or busy arterial roadways. The involvement of SFDPH and the application of air quality assessment tools are becoming standard practice in the environmental review process of the San Francisco Planning Department. Air quality assessment tools are also being used in the assessment of air quality conditions in established neighborhoods. For more information, see: http://www.sfphes.org/HIA_Tools_Air_Quality.htm
The San Francisco Noise Model (top)
The San Francisco Noise Model estimates community noise levels in all areas of the City based on the generation and dispersion of traffic and industrial point source of noise emissions. It has the capacity to include airports and mass transit when appropriate. The model can estimate current or future noise levels for a street, land use parcel, neighborhood, community, or an entire city. The model can also identify the need for noise mitigation measures which include: barriers, substitution of quieter vehicles and equipment, and rerouting of noisy traffic. The model is an integral part of the citywide noise enforcement program and is especially useful in determining the various permitted noise levels associated with zoning districts in the noise ordinance and the implementation of acoustical building code standards.
The San Francisco Noise Model can be used to identify those populations exposed to excessive noise. When coupled with other land use strategies, the Model can protect residents of new developments by ensuring that these homes are built to modern acoustical insulation standards. In addition the Model enables the identification of areas exposed to excessive noise and enables the implementation of mitigation measures which could include sound walls, electric trolley cars, hybrid buses, rerouting of heavy trucks, and reduced use of police and fire sirens. For more information, see: http://www.sfphes.org/HIA_Tools_Noise.htm
Vehicle-Pedestrian Injury Forecasting Model (top)
The Vehicle-Pedestrian Injury Forecasting Model predicts change in the number of collisions resulting in pedestrian injury or death associated with area-level changes in street, land use and population characteristics due to new development or transportation system changes. SFDPH uses this model to inform the need for pedestrian safety mitigations and improvements in the course of land use and transportation planning, to prevent people from being injured or killed by motor vehicles while walking on San Francisco streets. Significant predictors (census-tract level variables) in the current model are traffic volume, employee population, arterial streets (%, without MUNI transit), resident population, neighborhood commercial areas (%, land area), below poverty level (%, population), land area (square miles), age 65 and older (%, population).
SFDPH began developing this multivariate model to understand how changes in traffic and other environmental factors impacted by development decisions in SF predict vehicle-pedestrian injury collisions. The main aim of the application of the Model is to inform the need for pedestrian safety mitigations and improvements in the course of land use and transportation planning. SFDPH published the pedestrian injury model findings in January 2009 in the professional scientific journal Accident Analysis & Prevention and is now writing a second manuscript detailing the practical application of the model to the Eastern Neighborhoods Area Plans in San Francisco. For more information, see: http://www.sfphes.org/HIA_Tools_Ped_Injury_Model.htm
Pedestrian Environmental Quality Index (PEQI) (top)
The Pedestrian Environmental Quality Index (PEQI) has been developed to assess the quality of the physical pedestrian environment and inform pedestrian planning needs. The PEQI draws on published research and work from numerous cities to assess how the physical environment impacts on whether people walk in a neighborhood. The PEQI is an observational survey which quantifies street and intersection factors empirically known to affect people’s travel behaviors, and is organized into five categories: traffic, street design, land use, intersections, and safety. Within these categories are 30 indicators that reflect the quality of the built environment for pedestrians and comprise the survey used for data collection. SFDPH aggregates these indicators to create a weighted summary index, which can be reported as an overall index or deconstructed by pedestrian environmental category or even by each indicator.
SFDPH began developing the PEQI in order to meet the need for a practical method to evaluate existing barriers to walking and prioritize future investments for increasing pedestrian activity and safety in land use and urban planning processes. For more information, see: http://www.sfphes.org/HIA_Tools_PEQI.htm
Bicycle Environmental Quality Index (BEQI) (top)
The Bicycle Environmental Quality Index (BEQI) is a quantitative observational survey to assess the bicycle environment on roadways and evaluate what streetscape improvements could be made to promote bicycling in San Francisco. SFDPH identified five main categories which embody important physical environmental factors for bicyclists: intersection safety, vehicle traffic, street design, safety, and land use. Within these categories, the survey has 22 empirically-based indicators, each of which has been shown to promote or discourage bicycle riding and connectivity to other modes of transport. Several of the indicators have been used in other bicycle indices from different regions in the country, while others are new concepts that have been found significant through other studies regarding healthy bicycle environments. These indicators can be aggregated to create the final index (the BEQI), which can be reported as an overall index score, and/or deconstructed by the bicycle environmental categories.
Results from the BEQI reveal the relative quality of the biking environment at a street-level scale in select San Francisco neighborhoods. Use of the BEQI can translate environmental variables into a set of provisions for a healthy bicycle environment and a BEQI assessment can inform neighborhood planning and prioritize improvements through the land use plans and environmental assessments. For more information, visit: http://www.sfphes.org/HIA_Tools_BEQI.htm
Retail Food Availability Survey (top)
The Retail Food Availability Survey is a survey which assesses the availability of healthy foods within stores, and therefore within neighborhoods, to determine community food security. This survey aims to examine the availability of certain foods, all of which are components of the USDA’s Thrifty Food Plan Market Basket, and other factors influencing food purchases within stores in low-income neighborhoods in San Francisco. The Retail Food Availability Survey can help assess food security in neighborhoods. The survey consists of store- and food-related measures such as store type, price, availability and variety, quality, organic produce, store characteristics (e.g., cleanliness), and demographic information. Low-income, minority communities typically have fewer supermarkets and grocery stores than higher socioeconomic status neighborhoods with primarily White residents, and therefore disproportionately suffer from problems of food insecurity. For more information, visit: http://www.sfphes.org/HIA_Tools_Retail_Food_Availability.htm
Pedestrian Flow Model (top)
The Pedestrian Flow Model is a practical forecasting tool which relates pedestrian activity at a street-level to modifiable environmental characteristics within developing and established mixed-use neighborhoods in San Francisco. SFDPH intends to apply this model to planning scenarios and infrastructure proposals emerging out of ongoing neighborhood planning efforts in order to identify and prioritize enhancements to the pedestrian environment. Pedestrian flow counts are generated at a street-level, accounting for the following built environment factors: street network configuration/connectivity, land use mix, street design, jobs-housing balance, transit system access, aesthetics, population and employment density, and safety. The primary aim of the Pedestrian Flow Model application is to identify the need and mechanisms for promoting pedestrian activity in the course of land use and transportation planning. For more information, visit: http://www.sfphes.org/HIA_Tools_Ped_Flow_Model.htm
Neighborhood Completeness Indicators (top)
Created as part of the HDMT, the Neighborhood Completeness Indicator (NCI) is a quantitative spatial assessment tool measuring the proximity of San Francisco residents to daily goods and services in their neighborhoods. Included in the NCI are 11 key public and 12 key retail services, necessary to meet the daily needs of neighborhood residents and to promote increased social interaction and increased walking and biking, thereby reducing daily vehicle trips and miles traveled. The NCI will be piloted this summer at Hope SF project sites to help identify service gaps in each neighborhood. For more information, visit: http://www.sfphes.org/HIA_Tools_Neighborhood_Completeness.htm
Income and Health Effects Modeling (top)
In 1999, SFDPH conducted an analysis of a proposed living wage ordinance for San Francisco. The analysis documented the benefits to adult health and children's education achievement attributable to the adoption of a living wage of $11.00 per hour. SFDPH found that adoption of the increased living wage would result in decreases in the risk of premature death by 5% for adults 24-44 years of age in households whose current income was around $20,000. For the offspring of these workers, a living wage would result in an increase of a quarter of a year of completed education, a 34% increased odds of high school completion, and a 22% decrease in the risk of early childbirth. In 2002, city legislators invited SFDPH to participate in city policy discussions on augmenting local minimum wage standard for all San Francisco residents. In 2003, San Francisco residents passed Proposition L increasing the minimum wage from $6.75 to $8.50 for over 50,000 workers in San Francisco. Other policy proposals with effects on wages in San Francisco could be similarly analyzed with respect to a number of health and social outcomes, including mortality, teenage pregnancy, and high school graduation rates. For more information, see: http://www.sfphes.org/work_living_wage.htm