The flue gas dispersion from the stack of a power station was investigated prior to addition of a high efficiency heat recovery facility. Decrease of the flue gas temperature from 115°C to 40°C by heat recovery could influence the local humidity and thermal NO x level. It might also result in the formation of a white large plume due to the early saturation of vapor around the stack, and deteriorate dispersion of thermal NO x . Numerical simulation revealed that the area influenced by flue gas has been enlarged, particularly in winter. The volume of visible plume indicating RH 1.0 increased to 120 m high and 80 m wide for the flue gas at 40°C, while a smaller plume was formed that was 85 m high and 50 m wide for that at 115°C. The humid air of the flue gas extended nearly 160 m further along the ground. The distance for the maximum NO 2 concentration on the ground increased by 80 m and 50 m for 1 m/s wind and 3 m/s, respectively. The area influenced at the ground level expanded more than 250 m at 1 m/s wind after heat recovery. In particular, lowering the temperature of flue gas may affect the local environment more significantly in unusual cases including temperature inversions.

Extreme recovery of the thermal energy from the combustion of flue gas may bring about early gas condensation resulting in the increased formation of nitric acid vapor. The behavior of the nitric acid formed inside the stack and in the atmosphere was investigated through a computer-aided simulation in this study. Low temperatures led to high conversion rates of the nitrogen oxide to nitric acid, according to the Arrhenius relationship. Larger acid plumes could be formed with the cooled flue gas at 40� � C than the present exiting gas at 115� � C. The acid vapor plume of 0.1 ppm extended to 25 m wide and 200 m high. The wind, which had a seasonal local average of 3 m/s, expanded the influencing area to 170 m along the ground level. Its tail stretched 50 m longer at 40� � C than at 115� � C. The emission concentration of the acid vapor in the summer season was a little lower than in the winter. However, a warm atmosphere facilitated the Brownian motion of the discharged flue gas, finally leading to more vigorous dispersion.

Formaldehyde is one of the most hazardous and typical indoor VOCs air pollutants. Asymmetric AgIO3 was respectively composited with 3D hierarchically structured BiOBr and 2D BiOBr nanosheets to photodegrade gas‐phase formaldehyde. Ag/AgIO3/BiOBr(CMC) demonstrated better photocatalytic performance than Ag/AgIO3/BiOBr owning to the role of biomass solvent sodium carboxymethyl cellulose in increasing the specific surface area, reducing the band gap and changing the dominant facets. Moreover, Ag nanoparticles coming from the reduction in AgIO3 were confirmed by XRD, SEM and XPS. The surface plasma resonance effect of Ag NPs improved the efficiency of the light quantum. Besides, different exposed facets of {010} in BiOBr(CMC) and {001} in BiOBr resulted in distinct oxygen vacancy structures. could be generated via a two‐electron transfer pathway on the {010} dominant facets surface in AABR‐CMC, leading to the change in photolysis pathway and facilitating more ·OH produced by AABR‐CMC. Compared with pure AgIO3 and BiOBr or BiOBr(CMC), the photocatalytic efficiency of the composites was improved significantly. Optimal photodegradation efficiency for HCHO was achieved for AABR‐75 and AABR‐CMC50.

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