Sacramento, CA (February 17, 2005)- The Air Resources Board’s (ARB) primary goal in developing this document is to provide information that will help keep California’s children and other vulnerable populations out of harm’s way with respect to nearby sources of air pollution. Recent air pollution studies have shown an association between respiratory and other health effects and proximity to high traffic roadways. Also, ARB community health risk assessments and regulatory programs have produced important air quality information about certain types of facilities that should be considered when siting new residences, schools, day care centers, playgrounds, and medical facilities (i.e., sensitive land uses). Sensitive land uses deserve special attention because children, the elderly, and those with existing health problems are especially vulnerable to the effects of air pollution.
Focusing attention on these siting situations is an important preventative action. ARB and local air districts have comprehensive efforts underway to address new and existing air pollution sources under their respective jurisdictions. The issue of siting is a local government function. As more data on the connection between proximity and health risk from air pollution become available, it is essential that air agencies share what they know with land use agencies.
The first section provides ARB recommendations regarding the siting of sensitive land uses near freeways, distribution centers, rail yards, ports, refineries, chrome plating facilities, dry cleaners, and large gas stations. This list consists of the air pollution sources that have been evaluated from the standpoint of the proximity issue. It is based on available information and reflects ARB’s primary areas of jurisdiction- mobile sources and toxic air contaminants. A key air pollutant common to many of these sources is particulate matter from diesel engines. Diesel particulate is a carcinogen identified by ARB as a toxic air contaminant and contributes to particulate pollution statewide.
Reducing diesel particulate emissions is one of ARB’s highest public health priorities and the focus of a comprehensive statewide control program. However, cleaning up diesel engines will take time as new engine standards phase in and programs to accelerate fleet turnover or retrofit existing engines are implemented. Also, these efforts are reducing diesel particulate emissions on a statewide basis, but do not yet capture every site where diesel vehicles and engines may congregate. Because living or going to school too close to such air pollution sources may increase health risk, these findings recommend that proximity be considered in the siting of sensitive land uses.
There are other key toxic air contaminants associated with specific types of facilities. Most of these are subject to stringent state and local air district regulations. However, what we know today indicates that keeping homes and other sensitive land uses from siting too close to such facilities would provide additional health protection. Chrome platers are a prime example of facilities that should not be located near vulnerable communities because of the toxic material used during their operations. For some facilities like gas stations, only the very largest would have the potential to cause any elevated health risk and only within a short distance.
In addition to source specific recommendations, these findings encourage land use agencies to use their planning processes to ensure the appropriate separation of industrial facilities and sensitive land uses. While some suggestions are provided, how to best achieve that goal is a local issue. In the development of these guidelines, input was received from local government about the spectrum of issues that must be considered in the land use planning process. This includes the benefits of urban infill, community economic development needs, and other quality of life issues. All of these factors are important considerations.
The purpose of this document is to highlight the potential health impacts associated with proximity to air pollution sources so planners explicitly consider this issue in planning processes. With careful evaluation, infill development and other concepts that benefit regional air quality can be compatible with protecting the health of individuals at the neighborhood level. One suggestion for achieving this goal is more communication between air agencies and land use planners. Local air districts are an important resource that should be consulted regarding industrial sources of air pollution in their jurisdictions. ARB staff will also continue to provide updated technical information as it becomes available.
Recommendations are as specific as possible given the nature of the available data. In some cases, like refineries, they suggest that the siting of sensitive land uses should be avoided immediately downwind. However, definition of the size of this area is left to local agencies based on facility specific considerations. Also, project design that would reduce air pollution exposure may be part of the picture and consultation with air agencies on this subject is encouraged.
In developing the recommendations, the first consideration was the adequacy of the data available for an air pollution source category. Using that data, they assessed whether one could reasonably characterize the relative exposure and health risk from a proximity standpoint. That screening provided the list of sources that they were able to address with specific recommendations. The researchers also considered the practical implications of making hard and fast recommendations where the potential impact area is large, emissions will be reduced with time, and air agencies are in the process of looking at options for additional emission control. In the end, recommendations were tailored to minimize the highest exposures for each source category independently. Due to the large variability in relative risk in the source categories, they chose not to apply a uniform, quantified risk threshold as is typically done in air quality permitting programs. Instead, because these guidelines are not regulatory or binding on local agencies, they took a more qualitative approach in developing the distance-based recommendations.
Where possible, they recommend a minimum separation between a new sensitive land use and known air pollution risks. In other cases, they acknowledge that the existing health risk is too high in a relatively large area, that air agencies are working to reduce that risk, and that in the meantime, they recommend keeping new sensitive land uses out of the highest exposure areas. However, it is critical to note that the implied identification of the high exposure areas for these sources does not mean that the risk in the remaining impact area is insignificant. Rather, they hope this document will bring further attention to the potential health risk throughout the impact area and help garner support for our ongoing efforts to reduce that health risk. Areas downwind of major ports, rail yards, and other inter-modal transportation facilities are prime examples.
As California continues to grow, we collectively have the opportunity to use all the information at hand to avoid siting scenarios that may pose a health risk. As part of ARB’s focus on communities and children’s health, we encourage land use agencies to apply these recommendations and work more closely with air agencies. We also hope that this document will help educate a wider audience about the value of preventative action to reduce environmental exposures to air pollution.
Air Quality and Land Use Handbook: A Community Healthy Perspective