What are the effects of air pollution?

Air pollution causes aesthetic loss, economic loss, personal discomfort and health hazard. Aesthetic effects include loss of clarity of the atmosphere as well as the presence of obnoxious odours. Atmospheric clarity loss may be caused by particulates and smog. Obnoxious odours encompass a range of potential air pollutants in gaseous form (hydrogen sulphide, mercaptans, etc.).

Economic Losses

Economic losses resulting from air pollution are:

(i) soiling

(ii) damage to vegetation

(iii) deterioration of exposed materials.

Soiling represents the general dirtiness of the environment that requires more frequent cleaning. Examples include more frequent washing of clothes, washing of vehicles and repairing of structures. Soiling is due fo particulate matter being deposited, with the key component being settle able particulate matter.

Most of the damage to vegetation is due to excessive exposure of gaseous air pollutants. It has been reported that settle able particulates also disrupt normal functional processes within vegetation and thus undesirable effects take place. An example is the deposit of settable particulate around cement plants. The air pollutants of greatest concern to agriculture are ozone (0₃), sulphur dioxide (S0₂), nitrogen dioxide (N0₂), peroxy acetyl nitrate (PAN), etc.

Plants are damaged by both acute injury in which pollutants attack cells and chronic effects related to disruption of chlorophyll synthesis. The low concentration of pollutants for a long period of exposure may significantly decrease crop yields without visible damage.

Deterioration of Exposed Materials

The deterioration of exposed materials includes the corrosion of metals, weathering of building materials, discoloration of paint, cracking of rubber, weakening of fabrics and fading of dyes. Sulphur dioxide accelerates the corrosion of metals, necessitating more frequent repainting of metal structures. The weathering of building materials is attributed to the effects of acidic mists formed in the atmosphere as a result of oxidation processes combined with water vapour. Examples of acidic mists include sulphuric acid and nitric acid.

Health Effects

The health effects range from personal discomfort to actual health hazard. Personal discomfort is characterized by eye irritation and irritation to individuals with respiratory difficulties. Eye irritation is associated with oxidants such as ozone and PAN and others. People who have respiratory diseases such as asthma, bronchitis and sinusitis suffer increased discomfort due to oxidants, nitrogen oxides and particulate matter.

The effects of various pollutants are summarized.

Prevention and control of air pollution

Basically, three means are available to control pollutant discharges into the atmosphere and to reduce their detrimental effects. They are:

Utilizing, control equipment. Which removes pollutant before they are discharged into the atmosphere?

Source reduction. This can be achieved by raw material changes, operational changes or modification or replacement of process equipment.

Dilution of the pollutants. At the source by providing tall stacks. 4.6.1 Control of Particulate Matter

Air pollution control technology for particulate matter from stationary sources includes the following: .

1. Gravity settlers

2. Cyclones

3. Wet collectors or scrubbers

4. Electrostatic precipitators (ESP)

5. Fabric filters.