Tracing Back Pollution, pt.3: A Growing Risk

In the first two posts from this serie, we have looked at air pollutants emissions from power plants, industry as well as residential and commercial sources. There is only one sector left in this familiar figure, namely transport:

Source: Greenpeace, 2012.

Whilst SO2 and particulate matter emissions from the transport sector seem minimal (5% or less), it is an important source of NOx and CO, also volatile organic compounds (VOC). The share of vehicle emissions is higher in urban areas, especially in large cities. A study by Guan and Liu (2013) indicated that the transport sector is the largest source of NOx and the second largest source of total air pollution in Beijing (following the energy sector). Beijing has been shutting down and relocating factories since before the Olympics in 2008, yet car ownership is still rising despite restrictions on new license plates. It is expected to exceed 6 million in 2016 (Xinhua, 2012). 

Source: Guan and Liu, 2013.

Overall, car ownership reached 154 million in China in 2014, the second highest in the world next to the US. However, the ownership per capita was still only a fraction of that of the US, with only 113 vehicles per 1000 person (Xinhua, 2014). The world’s largest automative market expanded at a compounded rate of 24% per year between 2005 and 2011 and still has substantial growth potential. McKinsey predicted an average annual growth rate of 8% till 2020 (Huang, Liu and Hein, 2013). Thus, the share of the transport sector in air pollutants emissions is very likely to increase as well.

Large gross vehicle ownership is causing traffic congestions in many cities (see the following figure), which may further worsen air quality. Vehicles burn the most fuel while accelerating to get up to speed (Environmental Leader, 2012), thus constant accelerating and braking exhausts more pollutants. According to Song (2014), PM2.5 concentrations are more than 3 times higher during rush hours than during off-peak hours on Beijing’s West 2nd Ring road.

Another factor that needs to be considered is the emission standards. China’s current nationwide light-duty emission standard China IV is nearly identical to the Euro 4 standard in terms of limit values, which was phased out in Europe in 2009. The new China 5 standard with an implementation date of 1 Jan 2018 is almost equivalent to the Euro 5 standard, which had been replaced by Euro 6 standard last year. The emission standards for heavy-duty vehicles also follows their European precedents, with a delay of 7-8 years (Transport policy, 2015). Lower standards are linked to higher emissions. And the Volkswagen scandal has raised the question of how much should we trust manufacturers’ environmental claims (and also claims on safety?).

In conclusion, though currently less significant than other sectors, given the ongoing expansion of the automotive market and loose emission standards, the transport sector is likely to contribute more to air pollution in the future.