Air Pollution Overview

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Air pollution can take many forms, all of which can cause harm to our health and our environment. DHEC monitors air pollution in South Carolina, and part of that process involves identifying the sources of pollution in the air we breathe.

About 75 percent of air pollution originates from human-made sources, and their emissions are controlled through the federal Clean Air Act and individual state laws and regulations. The remaining 25 percent comes from natural sources.

We organize air pollutants into three 'source' categories: Mobile, Nonpoint, and Point.

Mobile Sources of Air Pollution

Mobile Sources include vehicles (such as cars, trucks and buses) and off-road equipment (such as boats, airplanes, lawn mowers, leaf blowers, and other agricultural and construction equipment). Bus and car lines around schools, gas-operated equipment used to maintain your yard, and gasoline and oil spills on the roads can all contribute significant pollution to the air.

Running vehicles and equipment generate air pollution when they are idling. In fact, any more than 10 seconds of idling uses more fuel than is required to restart the engine for most vehicles.

Mobile Source emissions contain carbon monoxide (CO) , particulate matter (PM) , nitrogen dioxide (NO2) , and Volatile Organic Compounds (VOC), which are also known as Hydrocarbons. They also greatly contribute to the formation of ground-level ozone. According to the U.S. Environmental Protection Agency (EPA), more than 200 million vehicles driving on U.S. highways contribute 77 percent of total carbon monoxide (CO) and 45 percent of nitrogen oxides (NOx) in our air.

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Documents linked below are in pdf format.

Nonpoint Sources of Air Pollution

Nonpoint Sources include small pollution sources like dry cleaners, gas stations, and auto body paint shops. They also include sources like heating and cooling units, fire places, paints and coatings in buildings, and even your neighborhood's barbecue grills. Waste disposal in the form of open burning, landfills, and wastewater treatment are significant area sources. There are few nonpoint source specific regulations other than those covering hazardous air pollutant sources.

Though emissions from individual nonpoint sources are relatively small, collectively their emissions can be of concern - particularly where large numbers of sources are located in heavily populated areas. Nonpoint sources contribute to over 50% of all particulate matter (PM) emissions, which is higher than point or mobile sources. They also emit Volatile Organic Compounds (VOC) (also known as hydrcarbons) and nitrogen dioxide (NO2) emissions, which contribute to the formation of ground-level ozone .

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Point Sources of Air Pollution

Point Sources include major industrial facilities like chemical plants, steel mills, manufacturing plants, power plants, and hazardous waste incinerators.

In South Carolina, the Bureau of Air Quality (BAQ) uses a permitting process to monitor point source air pollution. Safe limits and conditions are established for a business, facility, or industry that has an air permit, requiring regular reporting of the amount of air pollutants they use, produce, or store. BAQ inspectors are also sent to these facilities to assess compliance with their air permit's conditions. If the permit conditions are not met, State and Federal laws can require stiff penalties in the form of fines, requiring additional pollution control devices, or even suspension of their permits and facility shut-downs.

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Mary Peyton Wall, Manager, (803) 898-4064