By analyzing the mass concentrations and compositions of atmospheric PM_2.5 in Shaoxing from December 2019 to February 2020, the characteristics of carbon-containing components, water-soluble ions and metal elements were obtained. NO₃⁻, OC, SO₄²⁻ and NH₄⁺ were the main components of PM_2.5 in winter. The OC/EC ratio was 3.27, which proved the existence of SOC. The proportion of SOC in OC was 47.3%, which showed that secondary sources made a significant contribution. The values of OC/EC and NO₃⁻/SO₄²⁻ indicated that vehicle exhaust emissions also made a significant contribution to PM_2.5. Trace elements of Na, Ca, K and Cd had higher enrichment factor values and were enriched due to human activities. Finally, PM_2.5 sources analysis was performed by the positive matrix factorization model. The results showed that secondary inorganic salts (49.3%), motor vehicles and industrial sources (21.3%) and dust sources (17.0%) were the important sources of PM_2.5 pollution.

To characterize the temporal variation in and source contribution of volatile organic compounds (VOCs) in a polymer industrial park, a two-year offline monitoring campaign (2018–2019) at Shangyu Industrial Park in the Yangtze River Delta was conducted. The study quantified the VOCs composition, seasonal variation, and ozone formation potential (OFP), with source apportionment performed using the Positive Matrix Factorization (PMF) model. During the observation period, the average concentration of total VOCs in 2019 was 286.1 ppb, showing a 22.6% reduction compared to that in 2018. Seasonal analysis revealed decreases in the total VOCs concentration by 41.8%, 38.4%, and 6.1% during spring, summer and winter, respectively, while an increase of 13.8% was observed in autumn, primarily attributed to industrial restructuring in the second half of 2019. Notable reductions were observed in specific VOCs components: oxygen-containing volatile organic compounds (OVOCs), alkane, halogenated hydrocarbon, alkene, and alkyne decreased by 34.5%, 27.9%, 26.3%, 24.6%, and 20.4%, respectively. The average OFP in 2019 was 2402.0 μg/m³, representing a 1.8% reduction from 2018. Contributions to total OFP from alkane, OVOCs, alkyne, and alkene decreased by 32.9%, 26.0%, 20.7%, and 15.0%, respectively, while halogenated hydrocarbons and aromatic hydrocarbons increased by 50.1% and 7.0%. PMF analysis identified four major VOCs sources: industrial production (44.9%), biomass combustion (17.8%), vehicle exhaust (11.0%), and solvent usage (26.3%). From 2018 to 2019, contributions from vehicle exhaust and solvent usage increased by 4.8% and 5.9%, respectively, while industrial production and biomass combustion decreased by 10.5% and 0.3%.

To further illuminate the issue of coexisting PM2.5 and O3 pollution of the industrial city in China, this study carried out online observation of the concentrations and components of volatile organic compounds (VOCs) in Shaoxing in Zhejiang Province during the season prone to O3 pollution. The objective was to elucidate the emission characteristics and causative factors of VOCs—a shared precursor of both PM2.5 and O3—as well as to assess the ozone formation potential (OFP) and dissect the regional transfer and local sources. Over the observation period, the mean volume concentration of VOCs was 169.96 ppb. Halogenated hydrocarbon, alkane and benzene compounds predominated, representing 31.68%, 30.36% and 23.32% of the total VOCs concentration, respectively. The mean OFP of VOCs was 849.75 μg m-3, with benzene compounds, alkene, ketone and alkane being the chief contributors, accounting for 41.62%, 25.81%, 11.48% and 10.43% to the total OFP, respectively. Key reactive species included isoprene, m/p-xylene, toluene, 2-pentanone, n-butanal, o-xylene, ethylbenzene, methylvinvl ketone, 2,4-dimethylpentane and ethylene. Source apportionment analyses revealed that 46.26% of VOCs originated from neighboring provinces outside of Zhejiang Province, while contributions from other cities within Zhejiang Province, excluding Shaoxing, summed up to 36.05%. Conversely, Shaoxing’s local emissions constituted 17.69%. Among local sources, industrial process dominated at 64.51%, followed by solvent usage at 25.69% and mobile exhaust at 4.53%.