High-resolution mapping of vehicle emissions in China in 2008

摘要

This study is the first in a series of papers that aim to develophigh-resolution emission databases for different anthropogenic sources inChina. Here we focus on on-road transportation. Because of the increasingimpact of on-road transportation on regional air quality, developing anaccurate and high-resolution vehicle emission inventory is important forboth the research community and air quality management. This work proposes anew inventory methodology to improve the spatial and temporal accuracy andresolution of vehicle emissions in China. We calculate, for the first time,the monthly vehicle emissions for 2008 in 2364 counties (an administrativeunit one level lower than city) by developing a set of approaches toestimate vehicle stock and monthly emission factors at county-level, andtechnology distribution at provincial level. We then introduce allocationweights for the vehicle kilometers traveled to assign the county-levelemissions onto 0.05° × 0.05° grids based on theChina Digital Road-network Map (CDRM). The new methodology overcomes thecommon shortcomings of previous inventory methods, including neglecting thegeographical differences between key parameters and using surrogates thatare weakly related to vehicle activities to allocate vehicle emissions. Thenew method has great advantages over previous methods in depicting thespatial distribution characteristics of vehicle activities and emissions.This work provides a better understanding of the spatial representation ofvehicle emissions in China and can benefit both air quality modeling andmanagement with improved spatial accuracy.