**7. Wet scrubber**

*Agrometeorology*

tration of soluble ions like mainly SO4

slurry in WFGD (4.7 to 0.8 mg/m3

with improved technologies [58].

**6. Gaseous pollution control**

CNG reduce the SO2 emission [63].

and fast reaction.

LLTESPs (0.3 to 0.8 mg/m3

which is based on the boundary layer momentum theory. Particulate matter was the significant higher in base line (CT1) than CT2. CT3 technology is Electrostatic precipitator based and is use full to reduce the volatile organic compounds like acetaldehyde and formaldehyde produced during commercial cooking [55]. The efficiency of Electrostatic precipitators is reduced if the temperature of the flue gases increases. The low-low temperature EP (LLTESPs) is more effective in particulate matter removal in coal fired plants. This temperature can be control by using Wet flue gas desulfurization (WFGD) in ESP. The study was conducted to check the effectiveness of the LLTESPs and WFGD. The outlet samples indicate that the concentration of PM decreased with the decrease of temperature. The concen-

−2, Cl−

individuals to get rid of polluted air. The facemasks are most commonly used by the Chinese people during the extremely high days. The model showed that 100-point increase in air quality index increases 54.5% consumption of facemasks. 187 million dollars could be save if control on air pollution has been achieved and it can be used for the social welfare of the habitants [57]. To combat with the particulate pollution there is a need of the hour to control the emission sources of particulate pollution

**CO:** Catalytic converter (CC) is a device which is used to convert the hazardous exhaust gases to non-hazardous exhaust gases by using the simple technique of redox reaction. The working of CC is totally based on the catalyst used. For CO control the Silver is used as a catalyst. The more the catalyst, the more the active site

Catalysts were identified by BET, FTIR, SEM- EDX, XRD, XPS technologies [59]. A study revealed that ZnO–CuO created hetero-composites show selective CO detecting with T100 is in close vicinity to Topt to yield simultaneous CO detecting together with its 100% catalytic oxidation for detection devices. The initiated oxygen reacts immediately with adsorbed CO to provide desired CO detecting together with 100% CO oxidation [60]. Evidences showed that oxidative desorption of CO enhance if oxygen species are present. Fast slaking of platinum in water boost the oxidation by two processes. One of the processes is chemical oxidation by using molecular oxygen and other is Langmunir-Hinshel wood surface oxidation [61]. **SO2:** The usage of segmented multistage ammonia-based liquid spray with different oxidation potentials to remove sulfur compounds from gas. MnO2 filter are used to absorb the SO2 from the exhaust. There are many sources of SO2 production like agricultural heavy machinery, vehicles etc. In this technology MnO2 along with ozone gas is introduced and found that 90% SO2 absorption is possible with the addition of ozone. This system also has the ability to improve the NO2 exhaust [62]. The alternative methods to reduce sulfur emissions are the use of low sulfur fuel, scrubbers to lower the emissions from sulfur rich fuel. Low sulfur in fuel and use of

Oxides of sulfur (SOx) are produced and exhausted during the operations of petrochemical industry and cause harmful effects on environment. One of the technique is sulfur recovery unit (SRU) which is made up of Claus process for removal of huge amount of sulfur removal and afterward a tail gas treatment unit (TGTU) for the remaining H2S removal (SCOT process, Beavon sulfur removal (BSR) process, and Wellman-Lord process) and flue-gas desulfurization (FGD) processes

and NH4

+

) with respect to WFGD because the addition of gypsum

) [56]. Preventive measures have been taken by

decreases in the outlet of

**62**

In this technique, SO2 is absorb by the slurry of an alkaline chemical reagent, and SO2 (g) is either converted to liquid or solid.

**Lime/limestone scrubbing:** There are many sorbents but limestone is efficient for desulfurization process. Gypsum scaling is common when the CaSO4 is more than 15%. To avoid this scaling lime stone forced oxidation process is used. In this scaling oxidation of CaSO3 CaSO4 by blustering in the air (usually in the reaction chamber) [66].

**Sodium (hydroxide) scrubbing:** Sodium scrubbing liquor is very efficient in absorbing emitted SO2. It is usually used in industrial broilers.

**Ammonia scrubbing:** It is a unique and new technology, commonly used for desulfurization (DS) of flue gases, in this ammonia is used for DS and commercial grade crop fertilizer is produced. It is currently using by Dakota Gasification Company's (DGC) Synfuels Plant [67]. Further, electrostatic and electro-fabric precipitators are used to remove SO3 from the flue gases of coal power plants [68].
