Where does air pollution come from?
The Bay’s NOx airshed — the area where emission sources that contribute the most airborne nitrates to the Bay originate — is about 570,000 square miles, or seven times the size of the Bay’s watershed. Close to 50 percent of the nitrate deposition to the Bay is from air emission sources located in Bay watershed states. The other half comes from sources located as far away as Ohio, Canada and South Carolina. The nitrogen emitted throughout the airshed eventually reaches the Bay watershed’s rivers, forests and wetlands. Within the airshed, there are four main sources of airborne pollutants: stationary and area sources, mobile sources, agricultural sources and natural sources. • Stationary and area sources do not move; they have a fixed location. • Stationary sources are usually large point sources that release relatively consistent amounts of pollutants, such as power plants and chemical and manufacturing facilities. • Area sources are smaller, clustered sources that collectively produce
Ozone (or smog) is created by chemical reactions and sunlight. Pollutants like nitrogen oxides (NOx) and volatile organic compounds (VOCs) are called “ozone precursors.” They combine in the presence of hot, stagnant, sunny weather to create ozone (or smog). Ozone precursors in the San Joaquin Valley come from cars, trucks, buses, agricultural equipment, dairies, and consumer products such as paint and even hair spray. PM comes from agricultural operations, industrial processes, combustion of wood and fossil fuels, construction and demolition activities, and road dust kicked into the air. Windblown dust and wildfires also contribute to the problem. Diesel soot is of particular concern in the Valley, due to the high volume of trucks that use Highway 99. The geography of the San Joaquin Valley acts as a trap for these pollutants. Surrounding mountains trap airborne pollutants near the Valley floor where people live and breathe. Population growth also contributes to the problem, as more pe
VOCs (Volatile Organic Compounds) generally come from evaporated petroleum products. The main sources of VOCs are pesticides and fertilizers, motor vehicles, farming operations, petroleum production facilities, surface coatings, and solvents. NOx (Nitrogen Oxides) come from fuel combustion, both in motor vehicles and industrial processes. Power plants, factories, cars, trucks, and stationary engines all create NOx. Particulate matter (PM) comes from dirt roads, farming operations, industrial crushing and grinding, and windblown dust, among other sources. Combustion of fossil fuels, as well as burning garbage and agricultural products, also releases particulate matter into the air. Additionally, PM can be formed when chemicals such as NOx, sulfur dioxides, and others (including many of the same that form ozone) react and condense in the atmosphere. Emissions Inventory For detailed information on sources of pollution in a specific region of California, visit the California Air Resources
Air pollution is created from both mobile, stationary and area sources. Mobile sources include cars, trucks, trains, airplanes and construction equipment. Mobile sources cause about 75% of Pima County’s air pollution. The remainder comes from other sources including power plants, industries, businesses, homes and products we use.
Air pollution comes from many places. It can come from cars, trucks, trains, planes, and boats! In fact, practically any kind of vehicle creates air pollution. It also comes from factories, gas stations, power plants, and even our houses. At home, we cause air pollution every time we turn on a light because we use electricity to power the light. Grilling out in the backyard, also causes air pollution. One way in which we can’t help but produce air pollution is by breathing! Most creatures on earth breath in oxygen and breathe our carbon dioxide which is an air pollutant. A well known fact is that cows cause a lot of air pollution as they produce methane gas when ever they “break wind,” and apparently they do this a lot! Do You Produce Air Pollution? Everyone produces air pollution, the difference is that some people produce more than others. It is really difficult to add up how much pollution that you make in one day. Think about everything that you have done today from when you woke u
