[Evolution Characteristics of Atmospheric Formaldehyde Emissions in Guangdong Province from 2006 to 2020].

Atmospheric formaldehyde, a key precursor for ozone (O3) and secondary PM2.5, is carcinogenic and plays an important role in atmospheric photochemistry and the formation of secondary pollution. However, the lack of understanding of the emission sources of atmospheric formaldehyde limits the study on the formation mechanism of secondary pollution and the formulation of pollution control strategies. This study used the emission factor and source profile methods to establish the emission inventories of formaldehyde in Guangdong Province from 2006 to 2020 and identified the main emission sources of formaldehyde and spatial and temporal evolution characteristics. The results showed that the formaldehyde emissions in Guangdong Province fluctuated in the range of 39000-56000 tons during 2006 to 2020, exhibiting a very weak downward trend. Biomass combustion is an important source of formaldehyde emission in Guangdong Province, of which the contribution decreased from 58% in 2006 to 27% in 2020 owing to effective control measures implemented in Guangdong Province. The solvent use source became the predominant emission source of formaldehyde in 2020 by contributing up to 28%, primarily through plastic products and asphalt paving sources. The construction machinery and trucks fueled by diesel were important contributors of formaldehyde emissions from mobile sources. Although the formaldehyde emissions in the Pearl River Delta and the non-Pearl River Delta were equivalent, the spatial distributions showed that formaldehyde emission hotspots were concentrated in the center of the Pearl River Delta and the eastern and western areas of the non-Pearl River Delta. This was primarily because the solvent use and mobile sources were the main sources of formaldehyde emissions in the Pearl River Delta, whereas the biomass combustion source was the dominant source in the non-Pearl River Delta. Therefore, the formaldehyde emission mitigations of the industrial and mobile sources in the central region of the Pearl River Delta and the biomass combustion source in the western area of Guangdong should be further strengthened in the future.

[Volatile Organic Compound Emission Characteristics and Influences Assessment of a Petrochemical Industrial Park in the Pearl River Delta Region].

The petrochemical industry is one of the major emission sources of volatile organic compounds (VOCs). However, the current studies have mostly focused on the identification of the chemical characteristics of non-methane hydrocarbon (NMHC) VOCs species from the petroleum refining sub-sector. Research on the characteristics of VOCs components in oxygenated VOCs (OVOCs) species and other important sub-sectors is still lacking. Therefore, eight enterprises at a petrochemical industrial park in the Pearl River Delta region were carefully selected to represent three major subsectors, namely petroleum refining, synthetic materials, and organic chemicals, for the petrochemical industry. The VOCs (including 22 OVOCs species) from stack emissions and fugitive emissions, as well as nearby sensitive sites, were sampled, and the source reactivity (SR), the thresholds of malodor, and the carcinogenic and non-carcinogenic risks were assessed. The main results were as follows:① the VOCs concentrations of the stack emissions from the petrochemical industrial park were between 0.2-46.3 mg·m-3. The VOCs species were greatly affected by the type of after-treatment technology. A major VOC species emitted from the combustion-based after treatments was formaldehyde, whereas the species emitted from the non-combustion-based equipment were acetone, 1,3-butadiene, acrylic, and isobutane. ② The fugitive VOCs emissions from the petroleum storage tank area were dominated by alkanes, whereas the other fugitive emission sites and the sensitive sites were dominated by OVOCs such as acetone, formaldehyde, and ethyl acetate. ③ The SRs were mainly contributed by OVOCs, aromatics, and olefins, with average proportions of 43.1%, 24.2%, and 21.1%, respectively, with the major species being formaldehyde, acetaldehyde, m/p-xylene, ethylene, and toluene. ④ The malodor appeared both in fugitive emission areas and the sensitive sites. The main odor components were OVOCs such as n-butyraldehyde, propionaldehyde, hexanal, and valeraldehyde. ⑤ The non-carcinogenic risks occurred in the fugitive emission areas and the sensitive sites of resin, alcohol, and aldehyde production, which were mainly caused by OVOCs such as free acetaldehyde, acrolein, and propionaldehyde. No carcinogenic risk was found in any of the sampled sites. This research can provide scientific support for the formulation of priority VOCs species-based precise control strategies in petrochemical industrial parks.