How many of the following are TRUE statements 

1.Gaseous air pollutants: These are oxides of sulphur, nitrogen and carbon, hydrogen sulphide, hydrocarbons, ozone and other oxidants.

2.Particulate pollutants: These are dust, mist, fumes, smoke, smog etc.

3.Sulphur dioxide causes irritation to the eyes, resulting in tears and redness. High concentration of SO₂ leads to stiffness of flower buds which eventually fall off from plants.

4.The irritant red haze in the traffic and congested places is due to oxides of nitrogen.

5.Hydrocarbons are composed of hydrogen and carbon only and are formed by incomplete combustion of fuel used in automobiles.

6.In blood, when the concentration of carboxyhaemoglobin reaches about 3–4 per cent, the oxygen carrying capacity of blood is greatly reduced.

7.Smoke particulates consist of solid or mixture of solid and liquid particles formed during combustion of organic matter. Examples are cigarette smoke, smoke from burning of fossil fuel, garbage and dry leaves, oil smoke etc

8.Classical smog occurs in cool humid climate. It is a mixture of smoke, fog and sulphur dioxide. Chemically it is a reducing mixture and so it is also called as reducing smog.

9.the amount of oxygen required by bacteria to break down the organic matter present in a certain volume of a sample of water, is called Biochemical Oxygen Demand (BOD)

10.The prescribed upper limit concentration of lead in drinking water is about 50 ppb.