How to cite:

Author(s), Year, Name, Ranking at Beijing City Lab, http://www.beijingcitylab.com

E.g. Long Y, Wang J, Wu K, 2014, PM2.5 pollution of Chinese cities, Ranking at Beijing City Lab, http://www.beijingcitylab.com

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Road intersection density of each prefectural or above city in China defined as the ratio between the road intersection count within the urban built-up area of a city and the urban built-up area in square kilometer of the city. Road intersections are derived from the BCL data "21 Road junction density of China in 2011", and the urban built-up area of each city is interpreted from remote sensing images (2010).

We estimate total population of each Chinese city using sub-district level population documented in the 2000 and 2010 census. Shrinking cities are defined as those cities whose population in 2010 was not greater than that in 2000.

Note: 本排行中的地级及地级以上城市对应市辖区范围，县级市对应县域范围；部分城市2000-2010年间市辖区范围有所调整，这里以2012年的为准统计2000和2010的人口；市辖区和县域边界与乡镇街道办事处边界部分不完全重合，因此该分析结果有少量误差。

Reported by Pengpai in Chinese

We inferred urban land for all Chinese cities at the prefectural level and above in 1980 and 2010 from remotely sensed images. The ratio between urban land area in 2010 and that in 1980 is used to approximate the degree of urban expansion in individual cities.

Reported by 澎湃 in Chinese

Reported by 南方周末 in Chinese

The expansion of urban land during 2000-2010 was inferred from remote sensing images. We further distinguish between two types of expansion: planned and unplanned. Planned expansion refers to increased urban lands that fall within official urban growth boundaries (UGBs), while unplanned expansion is associated with urban lands spreading beyond UGBs. The amount of planned and unplanned expansion is determined by overlaying urban expansion with official UGBs maps, which are digitized from municipal master plans (see http://www.beijingcitylab.com/projects-1/2-urban-growth-boundaries/). The proportion of planned urban expansion to a certain degree reflects the effectiveness of land use controls in individual cities.

初步成果，还有很多纰漏，不代表任何实体单位的观点。

The data quality of Open Street Map in China varies a lot across cities. In this ranking, OSM road networks for China were downloaded on October 5, 2013. We also gather the ordnance survey map of China at the end of 2011 with detailed road networks to compare with the OSM road networks for each prefectural and above cities in terms of total road length. Cities are ranked by the ratio between total road length in OSM and the ordnance map.

Information about total urban lands of individual cities from 2007 to 2012 is collected from MOHURD (2013). As the result of Chinese urbanisation, adjustment of administrative divisions occurs frequently every year, making the city number in each level changes correspondently. For consistency, some city boundaries are merged and revised according to the latest administrative districts and city inventories in 2012 to ensure every single city comparable on the time dimension. According to the statistics, total urban land area of 654 cites in China reached 36,352 and 46,744 km² in 2007 and 2012 respectively. The average urban expansion rates of 654 cities raised to 4.5% in past five years. We list results for prefectural or above cities in China.

Ministry of Housing and Urban-rural Development of the People’s Republic of China (MOHURD), 2013 Chinese City Construction Statistics Yearbook 2012 (Beijing: China Planning Press)

Reported by Pengpai in Chinese

It should be noted that the urban land area in 2007 in some cities like Sanya is not consistent with that in 2012, and we used the urban land area in 2006 for calculating urban expansion rate for these cities.

注：部分城市如三亚的2007和2012年的官方统计数据由于统计口径等原因有矛盾，因此用2006年数据作为2007年计算扩张率。

From a dataset of national POIs, we gathered 5,237 religious facilities (like temples, churches and mosques) for various religions of 287 prefectural or above cities in China. We then ranked these cities in terms of facility number per 10,000 people.

We inferred the activity level of mobile internet users in Chinese cities, based on information about geotagged micro-blog messages (aka Weibo) for the first half of 2014. Data were collected and counted via Weibo API. Cities are ranked based on per capita geotagged weibos, reflecting the mobile penetration. Overall, the amount of geotagged weibos are positively correlated with total population in individual cities. We also notice large numbers of weibos per capita for tourist towns (e.g., Lijiang) and cities with relatively high livability (e.g., Xiamen and Chengdu).

We estimated 1-year-daily PM2.5 concentration at the Jiedao level for the whole China using both ground observations and remote sensing images.

China's Ministry of Environmental Protection (MEP) and its local agencies maintain a network of air monitoring stations for criteria pollutants. The network monitors the concentrations of particulate and gaseous air pollutants at the ground level. Not until 2013, China started to disclose information about fine particulates less than 2.5 microns in aerodynamic diameter (PM2.5). We have collected daily average PM 2.5 concentrations during April 08, 2013 and April 07, 2014 from 945 monitoring stations in 190 cities.

Considering the sparse distribution of monitoring stations in China, we use the MODIS AOD retrievals to improve daily PM2.5 estimates for the whole country. We obtained the daily MODIS AOD data (MOD04/MYD04, Collection 5) from the Atmosphere Archive and Distribution System. These AOD retrievals have been screened from cloud and bright surface. We extracted AOD at 0.55μm as the auxiliary information to predict daily PM2.5 levels.

We aggregate the sub-district PM2.5 exposure to the city level. We rank all cities in terms of days of exposure.

Reported by Pengpai in Chinese

We gathered 867,263 bus stops of 281 prefectural or above cities in China. Each bus stop was buffered by an air distance of 800 m as a proxy of bus service coverage area, and buffer zones of all bus stops were then merged to overlay with urban land of each city. Bus coverage ratio of each city, a key indicator of 公交都市(交通部), was calculated by dividing the area of urban land overlaid with bus service coverage area with the total urban area of the city.