As per the US Occupational Safety and Health Administration (OSHA) reports, poor outdoor air flow, fluctuating humidity and temperature levels, remodeling, and other activities in or near a building may contaminate fresh air flow into a building. Buildings today are either ultra-efficient and highly insulated or are built without appropriate ventilation in clustered space, both leading to air getting trapped inside by design. This hampers circulation resulting in stale air indoors.
Causes of Stale Air:
There are several factors that leads to the contamination of air indoors resulting in stale air. Here we are discussing the major source of pollutants that are found in high concentrations affecting the IAQ:
- Wearing out of Daily-Use Goods
From a simple pair of slippers to the wooden or plastic furniture, utensils, or an entire building itself, most daily-use products tend to wear out, decay, fade out, and erode after long term use. The wearing out results in finer dust particles after a prolonged duration of exposure to varied climatic conditions or due to friction caused to it. This reduction of objects into dust or other minute formations contributes to IAQ degradation.
- Biological Discharge
Biological discharges are contaminants that are released during human and animal bodily functions. Shedding of skin, discharge of bodily fluids such as sweat or urine, release of pathogens while coughing and sneezing, bodily odour of the occupants, and other similar discharges together toxify the IAQ. Having pets can too result in the indoor air getting sullied, as pets often shed their skin and hair (termed as pet dander), along with emitting other allergic impurities through saliva, feces, sweat, and urine.
- Emission from Building Materials
Building materials could be any material used in the construction of a building or a structure. Volatile Organic Compounds or VOCs are carbon-based vaporized chemicals that are emitted by building materials like cement, paints, solvents, upholstery fabrics, carpets, adhesives, varnishes, vinyl floors and from various others. These chemicals can have lethal impact on human health especially in young children and senior citizens, who are prone to respiratory diseases and other health issues. Formaldehyde, one of the most common VOC or rather VVOC (Very Volatile Organic Compound), is common in many building materials such as plywood, particleboard, glues and foam insulation. It can be a potential cause of cancer, mutations and other undesirable health effects.
- Common Indoor Activities
Indoor spaces require regular cleaning, dusting, washing, painting, and many more basic maintenance activities that may again release VOCs in the air. Some other common activities like cooking, burning of biomass fuel (mostly in low income countries), charcoal, kerosene etc. can release different kinds and levels of pollutants in the air indoors. These can vary from odour, smoke, ashes, VOCs, dust particulates, and harmful greenhouse gases like carbon dioxide, nitrogen oxides, sulfur dioxides and more.
- Use of Cosmetics and Personal Products
Beauty products, cosmetics, and toiletries are mostly rich recipes of different chemicals, hence potential VOC emitter, contributing to indoor air pollution. Air fresheners, perfumes, deodorants, disinfectants, sanitizers are most ignored contributors of VOCs, dust particulates, and harmful greenhouse gases like carbon dioxide, nitrogen oxides, sulfur dioxide and more.
