Air Quality & GHG


The regulatory environment for climate change is rapidly evolving. To help clients navigate through this complex and ever-changing situation, HELIX Environmental Planning (HELIX) provides guidance to both government and private industry on greenhouse gas policies and methodologies. We are experts with air quality and GHG emission analyses for environmental documents as well as impact statements.

Air Quality Impact Assessments

HELIX conducts air quality and air pollution analyses that meet California Environmental Quality Act (CEQA) and National Environmental Policy Act (NEPA) requirements, regional air authority regulations, and the transportation conformity requirements and general conformity requirements of the Clean Air Act Amendments of 1990. Our air quality specialists use industry standard models to calculate air emissions and pollutant concentrations from mobile, area, and point sources for a wide range of projects, including land use developments, highways, electricity generation, transmission lines, public transit, and airports.

Climate Change/Greenhouse Gas Emissions Analysis

TrafficCongestionIn response to growing scientific and political concern with global climate change, California has adopted a series of laws and regulations to reduce emissions of GHGs into the atmosphere from industrial, commercial, and transportation activities within the state. CEQA requires that project applicants quantify GHG emissions and demonstrate how projects will be consistent with state reduction goals.


HELIX provides a host of climate change services including GHG emission inventory analysis, GHG emission mitigation plan development, and climate change analysis. We use the most current methodologies to calculate GHG emissions from vehicle activity, electricity use, natural gas consumption, and energy use associated with the transport and consumption of water. We also provide guidance on how future projects will likely need to adapt to climate change.

Climate Action Plans/Energy Action Plans/Energy Assessments

HELIX prepares Climate Action Plans and Energy Action Plans, which are a set of strategies that guide community efforts for reducing GHG emissions. The measures focus on improving energy efficiency and conservation in residences and businesses, as well as reducing emissions from transportation. HELIX conducts energy assessments that demonstrate whether projects are consistent with Appendix F: Energy Conservation of the CEQA Guidelines.

Health Risk Assessments

Many local air districts require that a health risk assessment (HRA) be performed for projects involving the release of toxic air contaminants (TACs), such as diesel particulate matter from heavy duty diesel trucks, benzene from gasoline service stations, and other large TAC emissions from marine ports and airports. HELIX assesses potential health risks at sensitive receptors using toxic air emissions and health risk assessment tools in accordance with the California Office of Environmental Health Hazard Assessments and U.S. Environmental Protection Agency guidelines.

Services & Capabilities

Our specific services capabilities related to air quality and GHG include:

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