Sustainable transport plays an important role in helping Chinese cities address their debilitating air pollution. Photo by Da Yang/Flickr.

This is the first post of the "China's Clean Air Challenge" series, exclusive to TheCityFix. This series examines the increasing social, environmental, and economic impacts of the serious air quality issues in Chinese cities, and investigates the source of emissions and sustainable solutions.

Air quality is one of many tragic social and environmental issues China has faced during its rapid urbanization and motorization. In the 2013 State of the Environment Report, China's Ministry of Environmental Protection revealed that only 4.1% of the 74 surveyed cities met the new standards for fine particulate matter (PM2.5) emissions. According to its latest air quality report for the first half of 2014, only 6.8% of the cities met the PM2.5 standard. Using the World Health Organization's (WHO) standard – which specifies that PM2.5 concentrations must average below 25?g/m3 over 24 hours to be considered safe for human health – there are more than one billion Chinese people exposed to air quality considered unsafe for more than half of the year. January had the highest monthly PM2.5 emissions in the first half of 2014, with a concentration 26 times above the WHO standard for safe exposure at 671?g/m³.

Left: A thick layer of haze blanketed the North China Plain on October 9, 2014. On that day, PM2.5 levels were 13 times higher than the level the WHO considers safe for 24-hour exposure. The graphic on the right shows PM2.5 exposure intensity, calculated using days of heavy pollution and population density. Graphics via NASA and Beijing City Lab.

Hazardous-levels of PM2.5 exposure in China trigger tremendous public health problems. The WHO finds that there is a strong link between air pollution exposure and cardiovascular diseases – such as stroke and heart disease – and cancer. Children, women, the elderly, and the poor are the most vulnerable groups. According to the Organization for Economic Cooperation and Development's (OECD) recent report, outdoor air pollution kills more than 3 million people across the world every year, and contributes to health problems like asthma and heart disease for many more. Based on the value of death and illness, the total cost of China's outdoor air pollution was an estimated US$ 1.4 trillion in 2010, and this number is rising.

Outdoor air pollution is a silent killer of millions of people worldwide each year. Graphic by Su Song/EMBARQ China. Data from WHO.

Transport plays a key role in urban emissions

So what are the main sources of the China's air pollutants, especially PM2.5?  People from different areas of China might have different answers. In most rural areas – especially in inland China – the energy and industry sectors, as well as wood cook stoves, dominate emissions. But in urban areas and especially in megacities, transport is the major source of emissions and its share is growing due to urbanization and motorization.

The evidence is still building, but it is already clear that road transport is a significant contributor to urban air pollution. Motor vehicles are estimated to emit about 15-35% of local PM2.5 in Chinese cities. In Beijing, this number is estimated to be 31%; 25% in Shanghai; 23% in Guangzhou; 31% in Shenzhen; 20% in Chengdu; 33% in Hangzhou; and 14% in Qingdao.* Vehicle emissions also account for 58% of the nitrogen oxides (NOx), and 40% of volatile organic compounds (VOC) in Beijing – both of which can have serious negative health effects.

Rapid motorization in China – the driving force behind growing urban transport emissions – is causing the "growing pain" that many other developed economies have experienced before: congestion and air pollution, which costs citizens time and damages public health. Graphic by Su Song/EMBARQ China.

Congestion makes pollution worse

In a congested area where vehicles frequently stop and go, tailpipe emissions can be three times higher than when driving is smooth. For example, on Beijing's west second ring road, PM2.5 levels are 25-30?g/m3 when traffic is moving freely compared to 90-100?g/m3 during peak congestion. Unfortunately, congestion in big Chinese cities is sprawling to even larger areas as they grow, while small- and medium-sized cities face increasing congestion as they urbanize. These trends mean more people will be exposed to heavier air pollution.

Towards sustainable urban transport solutions

Various policy instruments can address these challenges:

• Emissions monitoring and evaluation. A sophisticated emissions monitoring and inventory system can help cities have a clear idea of their transport emissions and the associated social impacts, providing them a foundation on which to take action.
• Transport demand management (TDM). Various economic instruments like parking management and congestion pricing, together with regulatory instruments such as traffic and vehicle ownership restriction, can help cities create more efficient transport systems and encourage people to shift to public transit. In addition to improving air quality, an efficient transport system will create co-benefits such as reduced congestion and increased social equity.
• Technologies and standards. National and city governments should introduce stricter emission standards for all kinds of vehicles, especially for vehicles with diesel engines. Efficient 'green' technologies such as 'green' tires, diesel particulate filters, and hybrids and electric vehicles can also mitigate vehicle emissions.
• Transit-oriented development (TOD) and public transport. City governments should also introduce TOD by integrating urban and transport planning to more efficiently use land resources. Cities must also support efficient public transport services to increase mode share. Evidence shows that eliminating one car when a household shifts to public transport reduces the household's emissions by up to 30%. Furthermore, the indirect "leverage effect" of higher density around transit hubs can amplify the direct emissions reductions from public transit by 200 to 300%.

China's government should make air quality its top priority in the upcoming 13th Five-Year Plan. This five-year period from 2016 to 2020 is critical for air quality management, since 2016 is the first year of nationwide air quality standard enforcement, and 2017 is the deadline to achieve targets from the Air Pollution Prevention and Control Action Plan, which calls for PM2.5 reduction of 25%, 20%, and 15% for the Beijing-Tianjin-Hebei, Yangtze River Delta, and Pearl River Delta regions, respectively. Setting targets is the easy part, however. There is still a long way ahead.

* Author's note: These statistics were calculated using different methodologies, and therefore are not direct comparisons.