Air Pollution In California: China's Impact And Influence

California's air quality has been affected by air pollution from China, which is among the greatest emitters of air pollution in the world. Trans-Pacific air pollution from sandstorms in China has impacted the health of Californians, with studies showing a modest increase in acute respiratory disease per capita. While most air pollution in US cities is generated locally, researchers have found that Asian pollution, particularly from China, is consistently transported across the Pacific on air currents, affecting California's air quality and morbidity.

Trans-Pacific air pollution from China

The production of goods for export to the US and Europe is a significant contributor to China's air pollution, which then blows across the Pacific Ocean to the US West Coast. Powerful global winds known as "westerlies" can push airborne chemicals across the ocean in as little as five days, causing dangerous spikes in contaminants. This includes dust, ozone, and black carbon, which has been linked to various health problems, including increased asthma, cancer, emphysema, and heart and lung disease.

Addressing Trans-Pacific air pollution from China requires international cooperation and a shift towards reducing transboundary transport of air pollution. While China is taking action to reduce its energy consumption and air pollution, the challenge is daunting, and the environmental impact on California and other states continues to be a concern.

Sandstorms in China

In April 2013, a large sandstorm in the Gobi Desert led to a haze in Owens Valley, California a few days later. Studies have found that trans-Pacific air pollution from sandstorms in China can impact air quality and morbidity in California. For example, an increase in acute respiratory disease per capita has been associated with heavy sandstorms in China. China's pollution also affects neighbouring countries such as South Korea and Japan, and it has been predicted that global warming could change air circulation patterns, affecting the transport of pollutants from Asia to the US.

China is one of the countries most severely affected by dust-sand storms and desertification. The northern and northwestern regions of China are particularly vulnerable, with highly fragile ecological systems. Desertification is caused by various factors, including wind, water, alkalization/salinization, and freezing and melting processes. The frequency of dust storms in northern China has decreased in recent years, possibly due to greening efforts such as tree-planting projects. However, ecologists have expressed concerns about the use of non-native species and the long-term viability of these projects.

To combat desertification and reduce the negative impacts of dust storms, China is working on ambitious greening projects, such as the Three-North Shelter Belt, also known as the Great Green Wall. This project aims to establish forests along the edges of the Taklimakan and Gobi deserts to prevent the spread of deserts and improve air quality. While China has made progress in controlling desertification, collaboration with neighbouring countries in Northeastern and Central Asia is necessary to effectively halt widespread desertification.

Westerly winds

The impact of intercontinental air pollution from China on California's air quality and public health has been well documented. Studies have shown that during the spring, when the Westerly winds are strongest, between 12 and 24 percent of the sulfate-based air pollution over the Western US originated in China. This includes nitrogen oxides, carbon monoxide, ozone, and black carbon. These pollutants are known to have detrimental effects on human health, ranging from respiratory issues to heart and lung disease.

The production of goods for export to the US and other countries is a significant contributor to China's air pollution, with about one-fifth of its emissions stemming from manufacturing. This is particularly concerning for California as the state's environmental regulations focus solely on domestic pollution sources, neglecting the impact of foreign pollution emissions. The problem is further exacerbated by sandstorms in China, which can lead to worsened air quality and increased respiratory issues in California.

While the US has benefited from outsourcing production to China, enjoying cheaper imports and reduced domestic pollution levels, the environmental impact of China's industrial activity has become a growing concern. The increase in emissions from China has the potential to offset the gains made in the US through the reduction of nitrogen oxide emissions. This highlights the need for international cooperation and the implementation of clean-air treaties to address the complex issue of transboundary air pollution.

Chinese exports

A notable example of the impact of Chinese exports on air pollution in the United States is the effect of outsourcing manufacturing to China. While emissions reductions in the eastern United States have been observed due to this outsourcing, the western United States has experienced an increase in air pollution. Modeling results indicate that approximately 3-7% of annual mean surface sulfate concentrations, 2-5% of BC, and 2-5% of CO over East China in 2006 were attributed to the production of goods for US consumption. In the western United States, sulfate concentrations increased by 0-2%, and ozone and CO levels also saw a slight rise due to the transport of pollution from China outweighing the reduction in US emissions.

The "pollution haven hypothesis" proposed by Copeland and Taylor suggests that the reduction of trade barriers leads to the relocation of pollution-intensive industries from countries with stricter environmental regulations to those with more lax standards. China's accession to the World Trade Organization (WTO) in 2001 resulted in a significant increase in exports, contributing to both economic development and severe environmental issues. While China has implemented various environmental policies, such as the APCKZ policy and the Five-Year Plans, to address pollution, the rapid growth in exports has posed challenges in effectively controlling emissions.

Air pollution resulting from Chinese exports has had measurable impacts on the environment and human health. Studies have shown that increased pollution can negatively affect the productivity and innovation capacity of firms, as well as the health of employees. Additionally, the central region of China, the east of the Hu Huanyong line, and cities with low altitude and high pressure are found to be more vulnerable to the effects of air pollution on production and exports.

California's progress in reducing ozone

California has made significant progress in reducing ozone levels and improving air quality. The state has a long-standing commitment to a clean environment and has the economic resources to take a leadership role in combating climate change. Assembly Bill 32, passed in 2006, aims to reduce greenhouse gas emissions to 80% of 1990 levels by 2050.

In 2022, the California Air Resources Board approved a statewide plan to meet the federal health-based standard for ozone, which is typically experienced as smog. The State Implementation Plan (SIP) Strategy includes a range of measures to reduce emissions from sources under the state's authority, including regulations, incentive programs, and voluntary initiatives. The goal is to transition away from combustion and reduce the health impacts of air pollution, especially in low-income and disadvantaged communities.

One of the key challenges for California is addressing the issue of transboundary air pollution from China. While most air pollution in U.S. cities is generated locally, studies have shown that trans-Pacific air pollution from China can have a significant impact on air quality in California. Sandstorms in China and industrial pollution can lead to increased levels of ozone, particulate matter, and other pollutants in California. For example, a 2013 sandstorm in the Gobi Desert led to a haze in Owens Valley, California, and studies have found that up to 29% of lead in San Francisco can be traced to Asia.

Despite these external challenges, California has made progress in reducing ozone levels within the state. The South Coast Air Basin (SoCAB) in California has seen a long-term decline in O3 concentrations over the past four decades due to reduced anthropogenic emissions. However, recent progress has been limited, and O3 design values started increasing again after 2016. Additional measures, such as aggressive NOx reductions, may be needed to meet safe O3 levels and protect public health.

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