Air Pollution in San Joaquin Valley

Categories: Air Pollution

Air quality in the San Joaquin Valley is very poor.

The San Joaquin Valley is 27,000 miles long and consists of 62 different cities throughout California. Including, the following counties: Fresno, Merced, Tulare, Kings, Madera, Stanislaus, Kern, and San Joaquin. The San Joaquin Valley contributes to a majority of California’s agricultural production (Dhaliwal, 2014). However, according to the Environmental Protection Agency (EPA), the San Joaquin Valley’s air quality is very poor. This is due to the very unhealthy levels of ozone and particulate matter pollution in the valley (United States Environmental Protection Agency, 2018).

Ozone can be helpful or harmful. It can be found in the Stratosphere and the Troposphere. However, ozone reacts differently in both of these layers of the atmosphere. In the Stratosphere, it is beneficial and creates a shield from UV radiation from the sun (ozone layer). In the Troposphere, it acts as a pollutant. The Troposphere is the layer of the atmosphere that is closest to Earth (Cramer & Cheney, 2000).

Due to this, inhabitants on Earth are exposed to the chemical reactions that create ozone occurring in the Troposphere. This causes serious problems for inhabitants on Earth.

According to Cramer and Cheney (2000), during the summer, the San Joaquin Valley experiences warm and dry days. The average temperature is around 90 degrees and can reach over 100 degrees on certain days. During the winter, the valley’s weather cools down. The climate throughout San Joaquin Valley contributes significantly to the poor air quality. Ozone is considered a secondary pollutant formed by chemical reactions between reactive organic gases and oxides of nitrogen.

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This reaction is triggered by temperature and sunlight. Thus, there is a higher concentration of ozone during the summer when the temperatures rise. Throughout the day, higher concentrations are found when it is the warmest. At night, ozone concentration lowers (Cramer & Cheney, 2000).

Particulate matter is any solid or liquid material in the atmosphere. This includes materials such as, smoke or dust. According to Ngo et al. (2010), the San Joaquin Valley continuously fails to meet the healthy level of particulate matter in the air. There are three different classifications of particulate matter and each one has different effects (e.g. PM 0.1, PM 2.5, PM 10). In size, they can range from < 0.1 microns to Geography of San Joaquin Valley

In order to manage air pollution more effectively, California has 15 different air basins. The areas within each basin have similar features (geographical & meteorological). The basins are different in sizes, some are large, and some are small. The San Joaquin Valley air basin is surrounded by mountains (California Air Resources Board, n.d.). To the west of the San Joaquin Valley, the Coast Mountain range lies. The Coast Mountain peaks can be more than 5,000 feet high. Towards the east of the valley lies the Sierra Nevada mountains, with peaks more than 13,000 feet high. To the south of the valley lies the Tehachapi Mountains, with peaks more than 6,000 feet high. The valley does not have any mountain ranges to the north of it (San Joaquin Valley Air Quality, n.d.).

As mentioned earlier, there are three mountain ranges surrounding the basin, Coast Mountain, Sierra Nevada, and Tehachapi Mountains, each of these mountains prevents air from flowing into and out of the valley. The San Joaquin Valley basin also experiences poor wind patterns. The wind is a form of transportation for pollutants. The wind transports pollutants from the bay area into the basin. However, during the day pollutants can be transported out of the San Joaquin Valley basin through the south. At night, pollutants cannot exit the basin, through the south, because of cooler winds produced by the mountain ranges surrounding the basin. Due to this, the wind circulates back into the north (San Joaquin Valley Air Quality, n.d.).

Causes of Pollution

The San Joaquin Valley has a large population that has continued to grow throughout the years. Population growth is a factor that has affected the amount of pollution in the valley. A higher population means more sources of pollutants. Human activity is one source that causes pollution. According to Cramer and Cheney (2000), there is a positive relationship between population and emissions. As one increases, the other does as well (Cramer & Cheney, 2000). Pollution is produced through many human activities, such as recreation, heating, etc. However, most of the air pollution in the San Joaquin Valley is produced through agricultural production (Lin, 2013).

As mentioned earlier, the San Joaquin Valley contributes significantly to California’s agricultural production. Due to this, the valley uses a variety of agricultural equipment and practices that contribute to the valley’s pollution problem. For example, the vehicles used for production emit certain gases, such as ammonia and carbon monoxide. These gases can lead to secondary pollutants being formed (Lin, 2013). Not only that, but fertilizers and livestock also contribute to pollution (Lin, 2013).

Economic Impact

According to Kim, Helfand, and Howitt (1998), air pollution in the San Joaquin Valley is affecting agricultural production in the region. The San Joaquin Valley produces about 60% of California’s crops. As mentioned earlier, the San Joaquin Valley experiences high levels of ozone. The valley grows numerous crops which are very sensitive to ozone. These crops include beans, onions, lemons, oranges, grapes, and cotton. The valley’s ozone concentration is higher than these crops can withstand, thus leading to crop damage. Crops throughout the valley are affected by high concentration of ozone by minimizing photosynthesis (Kim, Helfand & Howitt, 1998).

Less crops, in turn, means less income and higher prices. It is estimated that 34% of orange production will be lost due to high concentrations of ozone (Kim, Helfand & Howitt, 1998). This affects the economy in a bad way. If there is a surplus of crop productions, market prices would decrease. However, if there is a shortage of a certain crop, market prices can increase. For example, the San Joaquin valley produces more than 85% of grapes (Kim, Helfand & Howitt, 1998). If the production of this crop was affected, there would be a change in the market price.

Health Impact

Air pollution in the San Joaquin Valley and throughout the Unites States has a major effect on human health. There have been many studies that have analyzed the effect of ozone on human health. It can cause chest pain, coughing, and more serious effects such as respiratory diseases. The residents throughout San Joaquin Valley suffer from high rates of asthma (Meng et al., 2010). In 2001, the California Health Survey was conducted, and its results revealed that Fresno was among the top counties in California that showed a high prevalence of asthma. The California Health Survey also revealed that other counties throughout the San Joaquin Valley, such as Merced, Tulare, San Joaquin, etc., had a high rate of asthma related emergency room hospital visits (Meng et al., 2010).

In 2010, Meng et al., conducted a study to observe the impact that ozone and particulate matter had on participants who have asthma. Their study included 1502 participants who resided in the San Joaquin Valley and reported having a medical diagnosis of asthma. These participants resided in areas with relatively high levels of pollution. Participants were asked to report any asthma related symptoms (coughing, shortness of breath, etc.) they experienced throughout the day or week. Participants were also asked to report any asthma related hospital visits. The study was conducted over the course of a year. In the end, 25.7% of participants reported experiencing asthma related symptoms daily/weekly during the study. There was a significant increase in the daily or weekly asthma related symptoms in older participants. During the year, there was 9.2% increase in asthma related hospital visits. Their results indicated that there is a relationship between the two. The results also indicated that ozone and particulate matter contributed to more hospital visits among children with asthma (Meng et al., 2010).

Obstructive pulmonary disease is a respiratory disease that can be enhanced by pollution. According to Zorana (2012), obstructive pulmonary disease can block airways and make it difficult for individuals to breathe. This disease is projected to become one of the top three causes of death by the year 2020. Although, this disease is mostly caused by smoking (cigarettes), there has been an increase in the diagnoses of this disease. There is evidence that suggest that continuous exposure to environmental pollutants enhances and worsens the symptoms of obstructive pulmonary disease. In turn, this increases mortality rates in individuals who have this disease (Zorana, 2012).

Environmental pollutants can also cause or enhance cardiovascular diseases. According to Zorana (2012), diabetes is becoming more prevalent throughout the United States. There have been recent studies that have found an association between diabetes and air pollution. In a study conducted in the United States, individuals with diabetes were found to be more sensitive to air pollutants than individuals who did not have diabetes (Zorana, 2012). There is evidence that exposure to particulate matter pollution can affect blood glucose, cause insulin resistance, and tissue (adipose) inflammation (Zorana, 2012).

Furthermore, the American Cancer society was concerned about the overall increase in lung cancer. Particularly, lung adenocarcinoma. This subtype of lung cancer is more prevalent in individuals who do not smoke (Gharibvand et al., 2017). Studies have found a relationship between particulate matter, specifically PM 2.5, and lung cancer. According to the International Agency for Research on Cancer, classified particulate matter as a group one carcinogen (Gharibvand et al., 2017). Gharibvand et al. (2017) conducted a study to further asses the relationship between particulate matter (PM 2.5) and lung adenocarcinoma. They also assessed the relationship between ozone and particulate matter (PM 2.5) to overall lung cancer. A total of 80,044 individuals participated in the study. 81% of participants never smoked, while the remaining 19% were past smokers. The study was conducted over the course of 2 years. Gharibvand et al. (2017) obtained air pollution data from the Environmental Protection Agency (EPA). The researchers monitored the participants health throughout the study and 7.5 years after. According to Gharibvand et al. (2017), 164 individuals were diagnosed with adenocarcinoma lung cancer. The majority of the participants who developed adenocarcinoma lung cancer were outdoors more. In the study, Gharibvand et al. (2017), found a positive relationship between higher levels of PM 2.5 and increased (31%) lung cancer (Gharibvand et al., 2017).

Social Impact

Clearly, air pollution affects everyone. However, the effects are different depending on an individual’s/group’s socioeconomic status. According to Gray, Edwards, Schultz, and Miranda (2014), minority groups and those who are economically disadvantaged are affected more by air pollution. The areas these groups live in tend to experience greater levels of air pollution. Due to constant exposure to air pollutants, these groups tend to have poorer health compared to other populations (Gray, Edwards, Schultz, & Miranda, 2014).

There are also certain disadvantaged age groups that air pollution negatively impact. These groups are children and the elderly. Children are at great risk because they are constantly being exposed to air pollution. They are still developing and breathing in polluted air can have a lasting impact on their lungs. There have been studies that have examined the relationship between lung growth and air pollution. They found that adolescents who lived in areas of higher pollution as children have a higher risk of smaller lungs (Children and Air Pollution, 2018).

The elderly are highly susceptible to health diseases and air pollution has a different effect on their overall health. As you age, lung function reduces. Due to this, being exposed to air pollution can dramatically affect an elderly individuals’ lungs. This group may already suffer from pre-existing health conditions and being exposed to pollutants may worsen their health. It may even be fatal. Studies have shown that this group is particularly affected by particulate matter pollution (Simoni et al., 2015).

Climate Change and Air Pollution

According to Ganesh and Smith (2018), California has become warmer over the past years. It is the warmest it has been since data collected from 1949-2005. The data up-to-date reflects an overall increase of 3 F since previous years. In the San Joaquin Valley, there have been low levels of precipitation which have led to droughts during the years 2012-2014. These years are reported to have had the highest temperatures as well as being the driest. As mentioned earlier, the valley has the one of the worst air qualities. An increase in temperatures could increase air pollution. It was discussed that Ozone is typically higher in the summertime. If temperatures continue to increase, ozone concentration will also increase. Particulate matter concentration will also increase (Ganesh & Smith, 2018).

Thus, health, economic, and social problems will continue to prevail. The cost of healthcare will increase over the next years. Higher healthcare costs affect everyone but will have a more dramatic impact on special populations, such as low-income. The cost of controlling pollution will increase and there will be more government spending focused on creating healthier air. This means there could possibly be less spending on other areas, such as education, military, etc.

Existing Policies

In order to help reduce air pollution in the valley, the Air Pollution Control District has kept an eye on the concentration of air pollutants through monitoring sites. According to the California Air Resources Board, there are a total of 38 air monitoring sites throughout the San Joaquin Valley. The sites measure air pollutants which the EPA has listed as health hazards. These hazardous pollutants include particulate matter (PM10 & PM2.5), ozone, sulfur oxides, carbon monoxide, hydrocarbons, etc. In addition, during the summer there are also five Photochemical Assessment Monitoring Stations that capture VOCs, or volatile organic compounds (Air Monitoring, n.d.).

In 2004, the Air Pollution Control District adopted the Extreme Ozone Attainment Demonstration Plan. Although it as adopted in 2004, it was disregarded in 2005 and was not implemented until 2010. This plan was designed to reduce ozone air pollution. It was developed to provide healthier air throughout the valley and to also meet federal/state ozone requirements. In 2007, the Ozone Plan was adopted (Ozone Plans, n.d.). This plan was designed to reduce particulate matter and ozone in the valley. The Ozone Plan also called for technological advancements that would help reduce pollutants. Recently in 2016, the Ozone Plan was updated and called for meeting the eight-hour ozone requirement set in a plan introduced in 2008. The 2016 Ozone Plan called for further reductions of air pollutants. The district has implemented various particulate matter and ozone reduction plans throughout the years and has successfully managed to reduce emissions by 120,000 tons (Ozone Plans, n.d.).

In addition to the implementation of these plans, the district has also received millions of dollars in funding through the EPA. The district is continuing to research new developments in technology. These technological advancements will help reduce pollution caused by engines. The district has also done research related to health effects of air pollution. The EPA and the San Joaquin Valley District also inspect facilities throughout the valley to ensure that they are not violating their permits, which monitor emissions. If a facility is in violation, they are charged a hefty fine. In 2012, Kern Front Oil Field were fined $34,000 because they did obtain permits to emit greenhouse gases. Also, in 2012, Ralcorp’s Cottage Bakery was fined more than a million dollars for violating air pollution regulations (United States Environmental Protection Agency, 2018).


In conclusion, air quality in the San Joaquin Valley is very poor. This is due to a variety of factors including geographical, metrological, agricultural production, etc. Air pollution has many negative effects on the economy, human health, and socially. There have been efforts to try to reduce the amount of pollutants in the air. Pollutants have reduced but there is still a long road ahead to have healthier air.   


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Air Pollution in San Joaquin Valley. (2021, Oct 31). Retrieved from

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