Ever wonder what's in the air you breathe? It may look clean, but you cannot always see air pollution. If you've ever seen a brownish haze floating in the air, you've seen pollution.
Since emissions are directly related to air quality, it is vital to have a detailed air pollutant emission inventory to keep track of the gas and particulate pollutants emitted in the air. It's also required by law. The federal Clean Air Act (CAA) requires the Ventura County Air Pollution Control District to develop and periodically update an emission inventory.
It all goes back to our mission - to protect public health and agriculture from the adverse effects of air pollution by identifying air pollution problems and developing a comprehensive program to achieve and maintain state and federal air quality standards.
The EPA and CARB have set health-based standards for certain air pollutants, called "criteria pollutants." These include ozone, particulate matter, carbon monoxide, nitrogen dioxide, sulfur dioxide, lead, visibility-reducing particles, sulfates and hydrogen, sulfide. The EPA classifies Ventura County as a severe non-attainment area for the federal one-hour ozone standard. The county also is classified as non-attainment for the state ozone and particulate matter standards.
The emission inventory helps the District identify air pollution problems, and helps us formulate comprehensive programs to achieve clean, healthful air for Ventura County residents and visitors. Together with information from the District's air monitoring network and regional air quality models, the emission inventory helps pinpoint the reasons for our current air quality problems.
It also helps us identify workable solutions to improve air quality by predicting the future effectiveness of emission control, strategies combined with the effects of population growth, and changes in the economy. Finally, the emission inventory is used as a tool to gauge our progress toward meeting our short- and long-term clean air goals.
The emission inventory is a cross section of our air - a view of pollutants emitted during a specific time of year, or a representative day during a year.
Our air quality is the result of a mixture of pollutants added by many different sources, just like a loaf of bread is the result of a combination of its ingredients. The emission inventory accounts for the mixture of emissions and predicts future air quality.
Through air quality permits, the District allows certain amounts of emissions from different sources. However, the quantity and type of emissions can vary yearly because of changes in the economy, technology, air regulations, and other factors. Due to the dynamic nature of emission sources, the emission inventory is considered only an estimate of what is occurring.
The District's Planning and Evaluation Division sends emission inventory surveys to stationary sources in Ventura County. These sources include business, industry, and other special categories such as airports and harbors.
The surveys ask about the emission processes at each location such as hours of operation, fuel use, solvent use, and what changes occurred at the site. Sources emitting 25 tons or more per year are surveyed every year. Smaller sources are surveyed less often. The frequency of surveys depends on the air quality goals for the year and the target pollutants.
The inventory is updated yearly, based on the District's survey results and the most current research by the U.S. Environmental Protection Agency (EPA) and California Air Resources Board (CARB).
The emission inventory indicates what pollutants affect Ventura County's air quality and classifies those emissions into two main emission source categories: stationary sources and mobile sources.
These are divided into point and area sources.
Point sources are stationary sources identified individually due to the quantity or nature of their emissions. Stationary sources emitting 25 tons or more per year of any criteria pollutant (or its precursor) are considered "major" point sources. Stationary point source examples include power plants, oil and gas field operations, and manufacturing plants.
Area sources are stationary sources that individually emit smaller quantities of pollutants, but collectively can contribute significantly. Consequently, the District reports area source emissions by categories rather than by individual source. Types of area source processes include gasoline dispensing, auto body refinishing, architectural painting, residential heating, solvent cleaning/degreasing, and other industrial processes.
The emission inventory also identifies oil platform, boat activity, and commercial shipping emissions that impact Ventura County's air quality, but are located outside the District's jurisdiction. These are identified as Outer Continental Shelf (OCS) sources.
The District's emission inventory includes data about total organic compounds, reactive organic compounds, oxides of nitrogen, particulate matter, carbon monoxide, sulfur dioxide, ammonia and lead.
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