Though the impact of urban vegetation on air quality and the microclimate has attracted increasing attention, there have been few studies quantitatively assessing this impact in North China, where air pollution is severe. In this study, we investigated the impact of urban forests and urban parks on air quality and the microclimate in Jinan, northern China. Six sites were chosen to represent urban forest, urban park, and downtown areas, respectively. The results indicate that urban forest can effectively reduce PM_2.5 and ozone (O₃) concentrations in the warm season, when temperatures are higher and plants are lush. The PM_2.5 and O₃ concentrations in the urban forest areas were 6.3–6.5 μg m⁻³ and 21–23 μg m⁻³ lower than those in downtown areas during the period of 10:00–15:00. In contrast, urban park areas can reduce PM_2.5 concentrations but have little impact on gaseous pollutants such as nitrogen dioxide and O₃. Furthermore, both urban forest and urban park areas reduced temperatures, by approximately 4.1–6.8 °C and 1.36 °C, respectively, and increased relative humidity, by about 13.4–12.9% and 0.9%, promoting a more comfortable thermal environment for residents. Therefore, this study highlights the crucial role of urban vegetation in improving air quality and creating a comfortable environment for residents.

While air quality in China has improved significantly in recent years, the population is becoming increasingly vulnerable to air pollution due to the aging population. In this study, we assessed premature deaths attributable to long- and short-term exposures to PM_2.5 and O₃, as well as their driving forces in Shandong from 2014 to 2060 based on county-level near-real-time air pollutant concentration datasets and projected concentrations of PM_2.5 and O₃. We found that the concentrations of PM_2.5 and O₃ in most districts and counties from Shandong are still higher than the corresponding concentration limit of Grade II. Premature mortality caused by long- and short-term exposures to PM_2.5 decreased by 13,045 and 8092 in 2020 compared with those in 2014, respectively. Furthermore, premature mortality attributable to short-term exposure to O₃ was 36.08% higher than that due to short-term exposure to PM_2.5 in 2020. The results of the driving force analysis indicate that the health benefits brought about by the improvement in air quality have been offset by the changes in population age structure. In the future, the increase in O₃ concentration and population aging are the top two driving forces having adverse effects on the health burden. This study provides support for controlling the health risks of PM_2.5 and O₃ pollution, especially for the development of dual-pollutant concentration targets and synergistic control strategies.

Simultaneous measurements of atmospheric volatile organic compounds (VOCs), conventional gases and meteorological parameters were performed at an urban site in Jinan, East China, in June 2021 to explore the formation and evolution mechanisms of summertime ozone (O₃) pollution events. O₃ Episode Ⅰ, O₃ Episode II, and non-O₃ episodes were identified based on the China Ambient Air Quality Standards and the differences in precursor concentrations. The O₃ concentrations in Episode I and Episode II were 145.4 μg/m³ and 166.4 μg/m³, respectively, which were significantly higher than that in non-O₃ episode (90 μg/m³). For O₃ precursors, VOCs and NOx concentrations increased by 48% and 34% in Episode I, and decreased by 21% and 27% in Episode II compared to non-O₃ episode days. The analysis of the m,p-xylene to ethylbenzene ratio (X/E) and OH exposure demonstrated that the aging of the air masses in Episode II was significantly higher than the other two episodes, and the differences could not be explained by localized photochemical consumption. Therefore, we speculate that the high O₃ concentrations in Episode II were driven by the regional transport of O₃ and its precursors. Backward trajectory simulations indicated that the air masses during Episode II were concentrated from the south. In contrast, the combination of high precursor concentrations and favorable meteorological conditions (high temperatures and low humidity) led to an excess of O₃ in Episode I. Positive matrix factorization (PMF) model results indicated that increased emissions from combustion and gasoline vehicle exhausts contributed to the elevated concentrations of VOCs in Episode I, and solvent usage may be an important contributor to O₃ formation. The results of this study emphasize the importance of strengthening regional joint control of O₃ and its precursors with neighboring cities, especially in the south, which is crucial for Jinan to mitigate O₃ pollution.

Emissions from civil aviation not only degrade the environmental quality around airports but also have the significant effects on climate change. According to the flight schedules, aircraft/engine combination information and revised emission factors from the International Civil Aviation Organization (ICAO) Aircraft Engine Emission Databank (EEDB) based on meteorological data, the emissions of climate forcers (CFs: BC, CH₄, CO₂, H₂O, and N₂O), conventional air pollutants (CAPs: CO, HC, NO_X, OC, PM_2.5, and SO₂), and hazardous heavy metals (HMs: As, Cu, Ni, Se, Cr, Cd, Hg, Pb, and Zn) from flights of civil aviation of eight airports in Shandong in 2018 and 2020 are estimated in this study. Moreover, the study quantifies the impact of COVID-19 on civil aviation emissions (CFs, CAPs, and HMs) in Shandong, revealing reductions of 47.45%, 48.03%, and 47.45% in 2020 compared to 2018 due to flight cuts. By 2020, total emissions reach 9075.44 kt (CFs), 35.57 kt (CAPs), and 0.51 t (HMs), with top contributors being Qingdao Liuting International Airport (ZSQD) (39.60–40.37%), Shandong Airlines (26.56–28.92%), and B738 aircraft (42.98–46.70%). As byproducts of incomplete fuel combustion, the shares of CO (52.40%) and HC (47.76%) emissions during taxi/ground idle mode are significant. In contrast, emissions during cruise phase are the dominant contributor of other species with a share of 74.67–95.61% of the associated total emissions. The findings highlight the disproportionate role of specific airlines, aircraft, and operational phases in regional aviation pollution. By bridging gaps in localized emission inventories and flight-phase analyses, this research supports targeted mitigation strategies, such as fleet modernization and ground operation optimization, to improve air quality in Shandong. The study highlights how sudden shifts in demand, such as those caused by pandemics, can significantly alter emission profiles, providing insights for sustainable aviation planning.

Synergistic pollution and carbon reduction is central to China’s Dual-Carbon strategy, yet the structural constraints on its regional evolution remain insufficiently examined. Using panel data from 16 prefecture-level cities in Shandong Province over 2010–2023, this study combines a coupling coordination degree model, Dagum Gini coefficient decomposition, and a panel fixed-effects model. Three findings emerge. First, the coupling coordination degree rose from 0.760 to 0.847, but this improvement was driven almost entirely by pollution reduction. The pollution reduction composite index increased by 31.7%, whereas the carbon reduction composite index declined by 6.6%, producing a pronounced “rapid pollution reduction, stagnant carbon reduction” asymmetry. Second, the spatial pattern was characterized by city-level differentiation rather than an east–west gradient, with Binzhou and Rizhao lagging persistently. Third, the Dagum Gini coefficient declined from 0.088 to 0.068, with transvariation intensity remaining the dominant source of disparity throughout the period (contributing 40.6–63.6%), indicating the limited explanatory power of the circle-based classification. Energy intensity and secondary industry share were the most robust drivers, whereas R&D intensity was statistically indistinguishable from zero. Policy should therefore prioritize energy efficiency improvement and city-specific targeting of persistently lagging cities.