The next most important source of indoor air pollution is allergens. House dust mites (HDM) are very small insects not visible to the naked eye and the commonest source of allergy in the house. They are ubiquitous and thrive in a warm and moist atmosphere. They breed very fast and are very difficult to eradicate. Modern houses present ample breeding spaces for them in the form of carpets, curtains, mattresses, pillows, etc.
Exposure to HDM can be prevented by the frequent washing of linen and by encasing the mattresses and pillows in a non-permeable cover. Pets form an important part of life for some of us. But they can add plenty of allergens to our indoor atmosphere. Cats are notorious for doing this. Fine particles from feline fur can remain stuck to the upholstery and carpets for a long time even after the removal of the animal and lead to the worsening of asthma and skin allergies. Fortunately, owning to religious and social customs, cats are not popular pets in India. Dogs, however, are quite popular and can be as troublesome. Pets should be kept out of the bedroom and groomed frequently. To remove the fur particles, one has to use vacuum cleaners as the ordinary broom and mop are not effective.
Moulds, fungi and several other microorganisms thrive in damp condition and can lead to allergies as well as infection. Humidifiers the air-conditioning plants provide an ideal environment for certain types of bacteria and have led to major outbreaks of pneumonia. It is important to regularly clean the coolers, air-conditioners and damp areas of the house such as cupboards, lofts, etc., to minimize this risk.
Toxic gases can also pollute the indoor environment. Biomass fuels (wood, cow dung, dried plants) and coal, if burned inside, can lead to serve contamination by carbon monoxide (CO). The poor quality of stoves and other cooking or heating appliances that cause incomplete combustion of LPG can also lead to the emission of CO or nitrogen dioxide. Formaldehyde (a gas) can be released from adhesives that are used for fixing carpets, upholstery and also in making plywood and particle-board.
The passage tells us that Molds, fungi and several other harmful microorganism thrive in ________.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Damp and moist condition
The third paragraph begins: "Moulds, fungi and several other microorganisms thrive in damp condition". To thrive means to grow well. The passage also asks us to clean damp areas such as cupboards and lofts to reduce this risk.
Why the Other Options are Incorrect?
Option 1: Well ventilated condominiums — Incorrect. Not mentioned: a condominium is a building of flats, each owned separately. Good ventilation dries the air, which works against moulds; the passage does not mention such buildings.
Example: They bought a flat in a new condominium near the lake.
Option 2: Well designed chapels — Incorrect. Not mentioned: a chapel is a small church or a room for prayer. The passage says nothing about chapels.
Example: The school has a small chapel for morning prayers.
Option 3: Well maintained canteen — Incorrect. Wrong link: a well-kept place is clean and dry; the passage links moulds to damp places, not to canteens.