Mosquito coils
Mosquito-borne diseases such as malaria and dengue are one of the biggest health menaces. And the use of mosquito repellents such as mosquito coils is one of the most commonly used ways for mosquito control. However, studies[1] have shown that burning of one mosquito coil emits particulate matter which is equivalent to burning 100 cigarettes and PAH equivalent to burning 50 cigarettes. Moreover, the levels of PM2.5 and carbon monoxide are around 2,200 times and 10 times the limits permissible by the WHO, respectively, when the mosquito coil is burnt with doors and windows closed.
Perfumes and cleaning agents
Poor ventilation causes accumulation of indoor pollutants such as kitchen odors, dust, etc. So to improve the hygiene and make a house odor-free, air fresheners such as perfumes and scents are used. However, these products are loaded with various gases which act as indoor pollutants. The fragrance contains high levels of nitrous oxide, PAHs, benzene and carbon monoxide. Studies[1] have revealed that burning of scented candles can emit high levels of particulate matter such as PM2.5 and PM10.
Paints and seepage
Paints and varnishes used in houses emit high levels of volatile compounds and gases, which further increase the burden of household air pollutants. Faulty plumbing can cause seepage of water, which increases the incidences of wall dampness. This, in turn, can act as an ideal environment for the growth of bacteria, fungi, and molds. These microbes release spores, toxic compounds and volatile compounds which contribute to indoor air pollution.
Cooking
The method of cooking contributes to indoor air pollution. The levels of particulate matter released in the air during the cooking process are extremely high. Various cooking methods such as stir-frying, deep or shallow frying, charbroiling, roasting, and grilling have different emission levels of particulate matter. Moreover, oil used in cooking emits a significant amount of polycyclic aromatic hydrocarbons (PAHs), which further add to the household air pollutants.
Smoking
Tobacco smoking, be it first-hand, second-hand or third-hand smoke, within a house is a major source of indoor air pollution. First-hand smoke, also known as active smoking, is when a person who smokes is exposed to the smoke himself. Secondhand smoke is when other members in the house (mostly kids and elders) inhale the smoke when a person smokes. Third-hand smoke is when a person inhales the particles emitted while smoking which is settled on clothes, furnishings, hair, and floor.
Cigarette smoke contains 7,357 different chemical compounds which range from carbon monoxide, PAHs, phenols, nicotine, benzene, cyanide, formaldehyde, and heavy metals. Moreover, it also emits significant amounts of particulate, mainly PM2.5. Studies have reported that burning one cigarette can emit around 7 mg to 23 mg of PM2.5.