Non-road construction machineries (NRCMs) are crucial contributors to the air quality. However, the emission control for NRCMs has not been given sufficient attentions. This study develops nearly full volatility speciation profiles for six types of NRCMs by combine using the GC-MS/FID, PTR-QiToF-MS, and HPLC-UV measurements. Higher alkanes and OVOCs are predominant components in the emissions with total mass fractions ranging from 69.3 % to 87.0 %. The speciation emissions between the working and idling mode are different by a factor of 1–3, indicating the influence of operation condition on the chemical compositions. With the profiles and registration data, a source-specific speciation emission inventory of NRCMs in Shenzhen China was established. The inventory shows that construction sites are predominant sources with contributions of 94.5 % to the total emission of NRCMs. The excavators are the largest contributors, which account for 51.1 %, 47.5 %, and 58.6 % of the total emission, OFP, and SOAFP. The VOCs especially OVOCs, alkenes, and aromatic hydrocarbons play significant roles in ozone formation with contributions of 78.2 %. The IVOCs are predominant SOA precursors associating with the higher alkane emission. The higher alkanes are responsible for as high as 96.2 % of the total SOAFP. Results provide new insights into the future policy-making for pollution control of NRCMs in megacities.
Nitrogen oxides (NO, NO2, NOx) are crucial atmospheric trace gases, and their accurate measurements are key for understanding atmospheric chemistry. NOx analyzers based on different principles, such as molybdenum-catalyzed chemiluminescence (MCL), photolytic chemiluminescence (PCL), and optical spectroscopy, have been developed, but their operational stability and accuracy across various environments have not yet been thoroughly evaluated. In this work, we conducted a comprehensive comparison of thirteen NOx analyzers in MCL, PCL, and optical spectroscopy technologies under controlled conditions in a large outdoor simulation chamber (100 m3) and during a short-term field campaign. Standard calibrations before and after the comparison period showed a change in the calibration curve of < 10 %, indicating that all involved analyzers demonstrated good long-term measurement stability. However, the results from controlled-chamber experiments at various levels of relative humidity (RH), ozone (O3), HONO, peroxyacetyl nitrate (PAN), and large-molecule organic nitrates revealed that: all NO detection analyzers can be influenced by RH; MCL-based analyzers showed significant positive biases for NO2 in the presence of HONO, PAN, and organic nitrates due to non-selective conversion; optical spectroscopy-based analyzers generally displayed higher selectivity for NO2 and maintained long-term stability. Additionally, detecting NO at concentrations below 1 ppbv remains challenging, as all NO analyzers performed poorly during field measurements at these low concentrations. This work emphasizes the importance of accounting for systematic biases and nonlinear responses to varying interference levels and meteorological conditions in laboratory experiments and in field monitoring networks.
Coal gangue dumps are widespread, yet the soil-forming trajectory of gangue-derived Technosols in reclaimed systems remains poorly constrained. Reclamation commonly relies on imported topsoil, whereas promoting in situ soilization of coal gangue within engineered mixed layers could provide a soil-process-based alternative. We sampled a coal gangue dump reclaimed for more than ten years in Yangquan, China, using paired root-present and root-absent profiles. Topsoil, mixed layer soil matrix, mixed layer coal gangue surfaces, and deep coal gangue were analyzed by physicochemical tests, aggregate stability, scanning electron microscopy and XRD, and 16S rRNA amplicons with functional prediction; constrained ordination and piecewise structural equation modeling linked soil-forming status, community structure, and functional potential. Root-associated effects were concentrated on the mixed layer coal gangue surface: available phosphorus rose from 0.64 to 5.12 mg/kg and available potassium from 35.37 to 97.78 mg/kg. Root-absent conditions showed stronger salt accumulation, with an operational Fe(II) fraction about ten times higher and elevated chloride. Root presence was associated with higher from 66.47 % to 73.66 % and mean weight diameter from 1.256 to 1.543 mm, whereas deep coal gangue showed limited changes. Microbial communities and predicted KO profiles separated clearly between treatments, with 282 differential KOs. Overall, the mixed layer coal gangue surface is a pedogenetically active interface, and the proposed indicators provide actionable targets to steer gangue soilization toward stable Technosols while reducing long-term dependence on imported topsoil.
Phthalate esters (PAEs), widely used as additives in agricultural inputs, are pervasive contaminants in agricultural environments and may threaten pollinator health. In this study, worker bees of Apis cerana were orally exposed to an environmentally relevant five-PAE mixture at 0.1, 1, 10, and 100 μmol/L for 14 consecutive days to investigate its effects on the gut-brain axis. PAEs exposure significantly increased worker bee mortality, with mortality rates rising from 20.59 % in the control group to 47.89 %, 42.67 %, and 55.10 % in the exposed groups, respectively (p < 0.05), but did not significantly affect daily sucrose consumption, proboscis extension reflex learning, or short-term memory performance (p > 0.05). At the physiological and molecular levels, PAEs disturbed the expression of xenobiotic-metabolizing enzyme genes in the brain and midgut, altered the abundance of gut microbial taxa (e.g., Gilliamella apicola), and disrupted neuroactive substance homeostasis in both tissues. In the midgut, PAEs significantly decreased several neuroactive substances, with reductions ranging from 33.82 % to 56.17 % for γ-aminobutyric acid (GABA), serine, and tyrosine, while glutamine (Gln) decreased by 34.66 % (p < 0.01). In the brain, PAEs significantly increased Gln, glutamate (Glu), and acetylcholine levels by 25.45 %-50.22 % (p < 0.05), and significantly downregulated nmdar1 mRNA levels (p < 0.01). Collectively, these results suggest that environmentally relevant PAEs mixture exposure disrupts gut-brain axis homeostasis in A. cerana and is associated with Glu/GABA-Gln-related neurochemical imbalance, highlighting the potential ecological risk of PAEs to pollinators in agricultural ecosystems.
