Persistent Growth Of Anthropogenic Non-methane Volatile Organic ...

With rapid economic growth and urbanization, high concentrations of ground ozone and aerosols have caused severe adverse effects on air quality, ecosystems and human health (Monks et al., 2015; Lu et al., 2018). Non-methane volatile organic compounds (NMVOCs) play key roles in producing ozone and secondary organic aerosols (SOAs), and some NMVOCs are toxic. NMVOCs can be emitted from a variety of sources, including anthropogenic, biogenic and open biomass burning (van der Werf et al., 2010; Guenther et al., 2012; Li et al., 2017). Previous studies revealed that reducing NMVOC emissions from anthropogenic sources is crucial for controlling ozone and fine particulate matter (PM2.5; with aerodynamic diameters less than or equal to 2.5 µm) pollution in Chinese cities (Shao et al., 2009; Yuan et al., 2013; Jin et al., 2015).

Anthropogenic NMVOC emissions over China have been estimated in various global and regional emission inventories (e.g., Klimont et al., 2002; Bo et al., 2008; Zhang et al., 2009; Li et al., 2014; Wei et al., 2014; Wu et al., 2016). Despite considering local statistics and measurements, uncertainties in NMVOC emissions are still high, i.e., ±68 %–±78 %, due to a lack of accurate information for a variety of sources such as solvent use, residential fuel combustion, etc. (Zhang et al., 2009; Kurokawa et al., 2013). In recent decades, dramatic changes in NMVOC emissions have taken place in China that are driven by economic development as well as implementation of control measures for the major sectors of industry, residential use and transportation (Wu et al., 2016; Li et al., 2017; Zheng et al., 2018). Energy-efficient and environmentally friendly technologies have been gradually introduced into the market. In addition, China has implemented stringent clean air policies to mitigate emissions in recent years, driving the significant reductions in emissions of air pollutants during 2013–2017 (Zheng et al., 2018).

Considering the large variances in chemical reactivity for different species, long-term chemically resolved emissions are urgently needed for tailored air pollution control measures in China. Previous efforts have been made to estimate speciated NMVOC emissions for China (e.g., Zhang et al., 2009; Li et al., 2014; Wu and Xie, 2017), but a long-term speciated NMVOC emission inventory over China is still missing. Chemical profiles are recognized as the major uncertainty sources for a speciated NMVOC emission inventory. For instance, oxygenated volatile organic compounds (OVOCs) were always missing in early measured source profiles (Liu et al., 2008). To reduce the uncertainties introduced by profiles, Li et al. (2014) developed a speciated NMVOC emission inventory over China for the year 2006 based on a composite source profile database with correction for OVOC fractions. Recent work has compiled an updated source profile database covering most species with inclusion of local measurements in China (Mo et al., 2016). However, these updates have rarely been used in developing long-term speciated NMVOC emissions for China. Here, we developed a long-term anthropogenic NMVOC emission inventory for China for the period of 1990–2017 by using updated activity data from the Multi-resolution Emission Inventory for China (MEIC) model framework (Liu et al., 2015; Li et al. 2017; Zheng et al., 2018) and a collection of state-of-the-art emission factors and source profiles.

The increasingly severe ozone pollution in China has been observed by the national monitoring network since 2013 (K. Li et al., 2018; Lu et al., 2018). Identifying the drivers of surface ozone rise is crucial for designing ozone control policy and protecting human health and ecosystems (K. Li et al., 2018). In the context of significant reductions for criteria pollutants such as NOx, SO2, CO and PM2.5 attributed to the implementation of control measures (Zheng et al., 2018), trends in NMVOC emissions and their potential effects on ozone production are critical for understanding the observed ozone trend and designing mitigation measures in the near future. Based on speciated NMVOC emissions developed in this work, we also estimate ozone formation potential (OFP) from different species and emitting sectors for the same period to inform targeted emission-control policies.