The San Joaquin Valley is a very uniquely situated area within the interior of California and due to its geographical location, there are both positive and negative effects. This 450-mile-long stretch of land is surrounded by mountain ranges. In the north there are the Cascades while the south contains the Tehachapi Mountains. On the east the San Joaquin Valley is bordered by the Sierra Nevada’s and finally on the west there is the Pacific Ocean. This set up has led to the run off of water from surrounding mountain ranges to fill up in the San Joaquin Valley for thousands of years until recently when we started developing dams. This yearly flooding of the Central Valley created very fertile soil and has allowed the valley to be a major agricultural provider. However, these surrounding mountain ranges also trap pollution and keep it stagnant within the San Joaquin Valley. Such pollutants are Ozone and particulate matters. Ozone found in the troposphere is a man-made pollutant that was introduced through the invention of internal combustion engines. By burning gasoline, we emit nitrogen oxide gases and volatile organic compounds or VOC’s. Particulate matter is mixture of different compounds and different sized particles that cause harm. These two pollutants are primarily responsible for the poor air quality and throughout this paper we will look into specifically when the levels of pollutants are at their worst and how the geography and agricultural activities aid in poor air quality. As the Earth’s climate changes so will the pollution levels within the valley; which will lead to economic, social, and health impacts of air pollution. Because the Central Valley struggles with poor air we have begun implementing policies to mitigate future air quality problems.
As stated above, the San Joaquin Valley is situated with mountain ranges surrounding it on three sides. Eight counties make up the San Joaquin Valley, which are Fresno, Kern, Kings, Madera, Merced, San Joaquin, Stanislaus, and Tulare. Each county struggles with poor air quality due to the bowl shape that the valley has. As each county begins growing this means more people, more cars, and more ozone and particulate matters created. These pollutants end up becoming trapped by an inversion layer which then leads all the pollutants to recirculate within the valley. As more and more pollution is put into the air the concentrations increase ( citylab). The San Joaquin Valley is known mostly for agriculture, it is one of the most productive regions in the United States, cultivating hundreds of fruits and vegetables, due to its fertile soil. With all the farming going on in the San Joaquin Valley we must account for all the emissions and particulate matter being produced. Tractors and other machinery release emissions into the atmosphere and tillage creates a great deal of dust putting more particles into the air. Recently the valley has been switching to a new form of tillage called conservation tillage where they leave the previous seasons crop on the ground before planting the next crop. In doing this it reduces erosion of the soil which reduces the amount of dust that is put into the air during tillage. There is less gas used and less work needed because tractors are passing over the field less which lowers emissions drastically. There is also a decrease in carbon dioxide lost to the atmosphere by oxidation of organic matter (conservation tillage).
Climate change is becoming a major issue worldwide, and it is gaining a lot of attention specifically in the San Joaquin Valley because of its agriculturally rich yields. California is becoming much hotter than it has been in the past. In 2014 temperatures increased by more than 3 degrees Fahrenheit than in 2005. Along with a decline in precipitation the valley experienced their driest and hottest year on record( climate change). As the San Joaquin Valley continues to heat up and experience low levels of rainfall; air pollution will continue to be harmful to its growing population. With a growing population there will be more emissions released with little rain fall to aid in clearing the air of these harmful pollutants. The increased temperatures will increase the reactions of nitrogen oxides and VOC’s leading to more tropospheric ozone created. Because the valley brings in so much for the economy it is vital that researchers develop methods in which the valley can mitigate these increasing levels of ozone and particulate matter.
There are a number of sources that make up for the regions poor air quality and no single one is solely responsible for it. The sources that are responsible are due to considerable amounts of traffic along the I-5 and Highway 99, tractors and irrigation pumps, wood-burning stoves and fireplaces, as well as locomotives (EPA). As a result of all this burning we get ozone and particulate matters that cause pollution. Ozone is primarily thought of to be beneficial to us due to its unique characteristics, which allows it to reduce the amount of harmful UV radiation that reaches Earth. This good ozone is referred to as the ozone layer and it is found in the stratosphere. When this gas is found within the troposphere that’s when it becomes harmful because we are now breathing it in. It is prominent within the troposphere because of internal combustion engines that burn and create nitrogen oxides and VOC’s that react with sunlight to create Ozone (EPA). There tends to be a variation, seasonally, when looking into how bad the air quality gets in the San Joaquin Valley. With seasonal changes come atmospheric changes that correlate with emission types and rates and atmospheric formation which effects the particulate matter in the valley. During the Fall and Winter, levels of particulate matter and Ozone tend to be higher than in Spring and Summer. This is primarily due to low wind speeds, colder, and more stagnant conditions producing a situation in which the accumulation of particulate matters is promoted. Temperature inversions are more prominent during winter and this causes particulate matter to become trapped below the mixing height and it is unable to combine with cleaner air higher in the atmosphere. The result of this is a layer of highly concentrated polluted air ( NASA). During the winter temperatures are often colder leading the public to be more inclined to use methods of burning to keep warm which add even more pollutants to the atmosphere than during summer time. Even though pollutants are fewer in Summer the San Joaquin Valley still struggles with air quality due to the fact that there is very little and most times no rain during this time. This reduces the number of events, such as rain, that aid in clearing pollutants from the area. During the nights cool drainage wind from the mountains prevent exit of the air at the southern end of the valley and often times bring back pollutants that had escaped to higher altitudes. These drainage winds cause the pollutants in the valley to recirculate in a counterclockwise motion, prohibiting clean air from coming in and increasing the concentration of pollutants. During the summer time temperature inversions do not tend to lay as low as inversions during the winter, so temperature inversions are not as harmful to air quality in summer (Nasa)
The San Joaquin Valley is impacted heavily by air pollution economically, socially, and in the residents’ physical health. From an economic standpoint, ozone levels significantly affect the San Joaquin Valley, who is one of the nation’s largest agricultural regions, bringing in roughly $2 billion with cotton and grapes alone (economic assessment). The Valley regularly experiences ozone pollution levels above standards set by state and national governments. When crops are exposed to ozone levels of this magnitude they often times suffer losses in yields. Because the San Joaquin Valley is an agricultural powerhouse any yield losses can be detrimental to the economy. Reduced ozone levels would ultimately increase the production yield in many crops located in the San Joaquin Valley. This would benefit our economy substantially by bringing in millions of dollars (economic assessment). If the San Joaquin Valley lowered ozone and particulate matter levels, its community would be healthier. Air pollution has been shown to have a negative effect during pregnancy and preterm births. Women were examined for levels of pollutants during their pregnancy at each trimester as well as the last month of pregnancy. The women that were exposed to higher levels of particulate matter pollutants within the San Joaquin Valley were more likely to have an early preterm birth. Often times preterm births lead to complicated medical problems in the neonate (preterm birth). Another major health issue in the San Joaquin Valley is asthma, which is a condition in which the lungs swell and make it more difficult to breathe. It is often times brought on by air pollution. Ozone and particulate matter levels influence the severity of asthma within certain people. The San Juaquin has high levels of pollutants and these can be a trigger to those with asthma making their condition worse in instances with increased levels of pollutants. Residents in the San Juaquin Valley report the highest rates of asthma symptoms and asthma related hospital visits in California (asthma). Individuals with asthma living in the San Joaquin Valley will be more likely to encounter frequent asthma related hospital visits due to the high levels of Ozone and particulate matter (asthma). These high levels of pollutions often times limit what the San Joaquin Valley’s society can do. Often times particulate matter levels are so high it is unsafe to be outside exerting energy and breathing in all the pollution, this affects the social aspect from air quality. School district within the San Joaquin Valley are notified by The San Joaquin Valley Air Pollution Control District when the standards for ozone and particulate matter are thought to exceed or if they have been exceeded. The air quality relates to whether or not it is safe for the children to be outside. Many of the schools put up a flag which is associated with the five categories of air quality. In doing this the children are able to see the flag’s color and understand the forecast of that day’s air quality. Green represents good, yellow represents moderate, orange represents being unhealthy for sensitive groups, red is unhealthy, and purple is very unhealthy/hazardous. With the green and yellow flags up outdoor activities are permitted. When the orange flag is up outdoor activities are permitted only certain times of the year. However, when red and purple flags are up students can only participate in indoor activities. This is why the valley is continuously trying to limit these pollution levels and make the San Joaquin Valley’s air quality better(http://www.valleyair.org/programs/ActiveIndoorRecess/What%20Color%20is%20your%20Flag%20Policy.pdf)
California’s interior San Joaquin Valley contains some of the nation’s highest levels of ground level ozone due to vehicle emissions. Because there are such high levels of ozone being produced in the valley California has a Smog Check Program. This program requires cars to pass an inspection based on an emission test, visual test, and functional test. In order for any car to be registered or sold in California they must pass this inspection. This inspection is a lot stricter here in California than it is in most other states. A non-profit group, Valley Clean Air Now, is trying to help reduce vehicle emissions in the San Joaquin Valley. They started a Tune In and Tune Up program that aids vehicle owners who cannot afford to pay for smog repairs. They are trying to mitigate pollution generated by older cars (vehicle emissions). California also is transforming the agricultural exemption from the Clean Air Act’s permitting requirements. So previously there was essentially no regulation on agricultural emissions. The Environmental Protection Agency ended the exemption in 2002 which would aid in reducing emissions from agricultural sources. This would ultimately help decrease the high levels of ozone and particulate matter that we see in the San Joaquin Valley (targeting agriculture).
The San Joaquin Valley is such a vital part of California, as well as the United States, due to its agricultural productivity. Something needs to be done about ozone and particulate matter levels because they are increasing more as the region grows. These high levels are harmful to, most importantly, the inhabitants of the San Joaquin Valley and also the region’s economy. Thankfully we have put policies in place to help lower the levels of pollutants, this is something that the San Joaquin Valley will struggle with for maybe all of its existence due to its geographical location that essentially keep all of the pollutants concentrated within its bowl shape.