27 INDOOR AIR QUALITY (IAQ) CONCEPTS, ZERO OR LOW VOC PAINTS

S. Visalakshi Rajeswari

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Introduction

 

Outdoor air pollution can be attributed to emissions from vehicular traffic, factories/ industries, agricultural activities, photochemical smog in the ambient atmosphere and other places specifically involving combustion processes. Bio aerosols from natural microbial activities can also contribute to air pollution. The worst part is that these aspects contaminate the air in the interiors too. They obtain entry into the indoors through open fenestrations and leaks in building envelope or through infiltration.

 

Objectives

 

Gain basic knowledge on:

  •   The concept of Indoor Air Quality (IAQ)
  •   Major pollutants contributing to poor IAQ
  •    Sources of pollutants
  •    Health issues related to exposure to poor IAQ
  •    Low and zero VOC paints

Pollutants in the indoor air differ with the place of occurrence, namely, rural or urban. In urban areas it is mostly from industrial sources. Major source of air pollution in rural settings basically are from burning of fossil and organic fuels which give out methane and carbon gases and certain building materials. Oxides of nitrogen, carbon and sulphur, particulate matter, hydrocarbons, ozone and many other photochemical oxidants share the composition of pollutants in the air emerging from urban areas. In addition, radon from building materials, water and soil, formaldehyde from insulation, asbestos, mercury, man – made mineral fibers, VOC from paints, allergens, tobacco smoke and presence of microbes also contribute to pollution and ultimately ill health of urban population. These pollutants tend to re-circulate and achieve higher concentrations, especially in air conditioned rooms, where the ventilation level is maintained low.

Evidently sources of air pollution in the interior of buildings are effectively through the double concentrations of pollutants from the ambient environment plus those generated within the buildings. The significant fact to be noted is that indoor air can be polluted by either a specific source or several sources; they may be generated daily, periodically or once in a while. It is because the pollutants contributing to indoor air pollution and thereby the indoor air quality (IAQ)), emerge from multiple sources and multiple products.

 

One will be able to see even routine activities that get along smoothly cause air pollution without even people noticing it. It is evident therefore that many of the products in day to day use are precursors to indoor air pollution. There are different types of air pollutants. For ease they can be classified under seven groups.

Having come to know the sources of indoor air pollutants, it is inevitable people come to know about their influence on personal health and how it is caused.

 

Impacts on air quality

 

Pollutants cannot become health hazards just by their presence in the environment, here in the indoor area. When the concentration of pollutants goes beyond a particular or optimal level coupled with the time of exposure of the person to such concentrations it can lead to health hazards. Individual health status where one is more susceptible to effects of pollutants also ends up in harmful effects. Issues encountered with pollutants hence are not just dependent on the nature of pollutants and exposure time alone but also on the provisions made for sending such pollutants out into the ambient air from inside. This warrants provision of adequate ventilation facilities. Improper ventilation in rooms result mainly in increasing pollutant concentrations considered detrimental to health. Therefore good indoor air quality can be ensured only by planned buildings with adequate ventilation and avoidance of polluting products – purely a human endeavour. The extent to which the indoor environment can affect human health is dependent upon these four major interdependent aspects: physical factors, indoor air pollutant species, rate of emission and adequacy / inadequacy of ventilation. Proper selection, planning and execution of these aspects decide how the indoor environment can address indoor air quality and influence human health status. It can therefore be assumed that human activity is the root cause of good or poor indoor air quality.

 

Pollutants and sources

 

Products used by people in day to day activities like air fresheners, waxes and polishes used on furniture, various cleaning solutions, paints, pesticides, fabric softeners/ protectors, deodorants – all have inorganic or organic chemicals in their composition which pollute indoor air. Similarly, human beings get along involuntarily with their regular metabolic activities like respiration, perspiration, release of water vapour, heat and odours and other life sustaining activities like food preparation and storage. Prima facie they don’t seem to be in any way harmful; but in fact these reduce the concentration level of oxygen in the interior and increase CO2 levels. If there are smokers in the family, the nature of pollution need not be explained.

 

Another important source of pollution in the interior is fuel used and the combustion processes adopted by the family. Kitchens designed with poor ventilation, placing stove at floor level and improper use of vessels with incompatible base also account for higher concentration of pollutants, while using LPG.

 

The components in the products used by people further add to the pollution factor, though people are quite unaware of it. Majority of the products used contain synthetic polymers as essential ingredients. Furniture and furnishings people use are best examples. They are the major sources of organic and microbiological pollutants in indoor environments.

 

Binding materials used in making and or laying furniture and furnishing are the next culprits. Various kinds of resins and adhesives are used in joineries. Such resins and adhesives contain an organic compound called formaldehyde. Exposure to this gas at levels over and above 0.1 ppm (parts per million) can be detrimental to health. Health effects manifest as irritation in the eyes, nose and throat, cough, fatigue, wheezing, rashes in the skin, and other allergic symptoms. In some people it can also cause cancer. Very significant, but less known sources of formaldehyde in interiors are from pressed wood products. These contaminate the air circulating indoors. These contaminate the air circulating indoors. Likewise, a host of consumer products people use also contain formaldehyde, though users can feel little satisfied in that only a few of them release the gas in sufficient quantities to cause health problems. Hence, levels of formaldehyde released into the interiors are determined to a considerable degree based on the nature of the source of the gas and the total quantum of the material releasing it used in the building’s interior. To sum up, have an idea on the precursors, which can be found in all materials used in indoor environments. They are laminated wood, particle boards, asbestos, foam cushions & pillows, insulation, fiber glass and Radon 222 which are the major pollutants. The most important one is Radon.

 

Radon 222 is a radioactive gas which is again, to be precise, found to be a contaminant in tightly sealed buildings. Materials used for construction like the common brick, concrete rocks, aggregates, mortar mixes and other plastering materials – all emit this gas. Further the gas can be released from regularly used underground and domestic water, natural gas and soil and will easily pollute the indoor environment. Major action of radon gas lies in its ability to decay and release alpha particles which are dangerous to health.

 

These factors are ample proof to address how air in one’s living environment can be made poor in quality by one’s own actions and consumption patterns. To understand that the indoor air quality is poor and it is affecting the inmates it is necessary to check once in a while for the presence of a few symptoms, both in the indoor work environment and in houses.

 

Perceivable symptoms in human beings exposed to poor IAQ

  • More than one occupant show off common symptoms
  • Symptoms arise in people who spend longer duration in an interior
  •  Symptoms do not show up in people who are away from the house or indoor work spots for longer period of time
  • Health effects related to seasonal patterns
  • Occupants of newly built homes, renovated buildings, newly furnished homes and users of insulation materials (which contain Urea formaldehyde) if often complain of health problems not endured earlier, it is sure that they have inhaled air of poor quality
  • Guests and visitors may even complain of certain unusual symptoms or react so by sneezing, coughing etc.
  • People who are allergic to formaldehyde react even in commercial spaces dealing with furniture, textiles, clothing section in departmental stores, declaring that the air quality is poor
  • For some individuals’ places where ceiling, flooring etc are of particle board, cabinets / furniture of plywood paneling, foam furnishings are used, turn highly allergic and may show symptoms of health effects

Perceivable changes in the indoor environment showcasing poor IAQ

  • Corrective measures like provision of adequate ventilation reduces frequency of bouts of symptoms
  • Greater the humidity level (50 per cent or more), severe will be the symptoms
  • Mild and limited exposure to ventilation if induces irritation in eyes, throat or nose at just low concentrations of 0.1 ppm.
  •  Even change in activity levels of people in new environments prove their susceptibility to unusual air quality parameters
  • Newly constructed buildings: They are adjudged the worst to be occupied as they promote severe symptoms of health problems

IAQ versus human health

 

Indoor air quality highlights presence of chemical or biological pollutants or the absence of adequate ventilation in the occupied rooms and buildings. Air quality in an interior can affect human beings dependent on the nature of pollutants, their source/ concentration and duration of exposure. Effects therefore can be short tome or long time. Either ways, the affected individual suffers the consequences. It can range from ordinary sneezing, common cold to psychogenic diseases and even cancer. Short time exposure of course may cause only temporary bouts of illness, but prolonged exposure result in the individual falling prey to infectious diseases and chronic illnesses which cannot be cured or may require long time treatment. Temporary effects can become troublesome in the long run too. Both the conditions will affect an individual’s status of performance, efficiency, attendance and morale, especially of workers in the polluted environment. Have a look at such health effects of poor IAQ.

  •   Digestive /Intestinal disorders

These problems need special address because they may lead to even overall debility or death of a resident or worker.

 

Reducing poor IAQ in home environment: The following measures can be practiced

  • Have adequate fenestrations (open doors/ windows), ensuring ventilation
  • Prefer optimum circulation of fresh air and lighting to artificial sources
  •  Orient fenestrations to enable free entry and exit of air, smoke and fumes
  •  Use exhaust fans, open windows, chimney/ flues or hobs to facilitate exit of smoke and fumes
  • Use appropriate vessels on the stove, to prevent dissipation of heat
  • Avoid burning of coal, kerosene and biomass for cooking and heating purposes
  •  See to zoning restrictions and bye-laws before construction so as to avoid industrial areas and noisy traffic problems nearby

Reducing poor IAQ in other built environments: The following measures would help maintain permissible IAQ in all built environments

  • Ensure optimum or admissible temperature and humidity levels are maintained in the rooms/ buildings
  • Avoid use of harmful/ toxic substances like high VOC paints
  •  Use more of eco friendly materials in construction and finishes
  • Follow set back regulations, to ensure free entry of light and air circulation
  • Choose pressed wood products which are of lower emitting quality for construction and furniture; prefer those with phenol resins to those containing urea resins
  • Ensure mechanical air circulation in large spaces with more inhabitants using air conditioners and dehumidifiers
  • Curtail overcrowding in interiors, especially offices and public spaces
  •  Be cautious about the content of formaldehyde in furniture and furnishings
  • Insist on polyurethane coating on pressed wood products to reduce formaldehyde emissions
  • Opt to breathe fresh air once in a while

Other viable measures

  •   Awareness generation among people on the issues of poor IAQ and benefits of adequate IAQ
  •   Educating masses on methods to ensure adequate IAQ
  •    Encouraging use of eco friendly building materials in construction
  •   Disseminating knowledge on harmful effects of using toxic/ harmful products for building construction, decoration, insulation, other services and furnishing
  •   Motivating industries to manufacture eco friendly building materials and finishes
  •   Avoiding use of products which emit gases (like acetone and ammonia) which are highly volatile and toxic
  •   Avoiding preference for paints with high VOC content
  •   Inspecting materials used by promoters and builders and taking punitive action against defaulters
  •   Monitoring construction activities and traders for promoting eco friendly building materials and finishes
  •  Providing subsidy to industries that manufacture eco friendly building materials and finishes
  •   Implementing strictly the building codes recommended under schemes to ensure health and safety of occupants

The next factor leaving an impact on the health aspects of human beings in the interior is the presence of toxic gases from the chemicals used, especially emanating from paints. VOCs in paint are considered deleterious to the environment and specifically the workers who handle them on a routine basis.

VOC

 

They are gases containing Volatile Organic Compounds, emitted by various products. They are capable of causing short or long term health effects in human beings based on the nature, accumulation, level and duration of exposure.

 

Several human activities involving use of certain chemical consumer products (both from consumption and production) are found to give out toxic gases. Such sources it is estimated to emit approximately more than 140 Tera grams of carbon per year in the form of VOCs

 

Other pollutants emitting VOC in interiors

  •  New buildings (which have used abundant new materials generating VOC particles in a short time span)
  • Consumer products – new furnishings, wall coverings, \Office equipment – Photocopiers
  • Personal habits – smoking, use of dehumidifiers in winter
  • Rate of air exchange – very low in winter

Ill effects of VOCs in the interior environment

  • Sick building syndrome (Long time exposure and level of exposure to VOCs )
  •   Respiratory problems
  •   Sensory irritation symptoms (throat, eye, nose,skin) and allergy
  •    Visual disorders
  •   Memory impairment
  •    Immune effects in infants and children
  •   Carcinogenic
  •   Loss of coordination
  •    Nausea, dizziness and headache
  •    Damage to liver, central nervous system and kidneys
  •    Fatigue
  •   Nose bleeding

Measures to reduce exposure

 

o   Buying products containing low or no VOC

o   Buying the exact amount needed to avoid storing

o   Avoiding storage of chemical products

o   Providing well ventilated areas where products containing VOCs are used

o Reducing infiltration into buildings incorporating good mechanical systems and design assemblies

o Using eco friendly products, especially paints and coatings

o Use only low VOC or zero VOC paints in interiors

 

Low VOC/ zero VOC paints

 

Paints made of latex or recycled latex which are water based and those made of acrylic and milk paints qualify for being called low VOC paints. Labels in paint containers are supposed to give details on their VOC content as a mandate. The standard is <50g/l of VOC for referring to it as low VOC paint and < 5g/l of VOC to refer to paint as zero VOC paint.

 

Summary and Conclusion

 

These issues therefore are not individual affairs. They have to be approached on a large scale not only by the beneficiaries (occupants) of the buildings but also all the stakeholders who have stakes in this aspect like industries, companies, builders, promoters, architects, civil engineers, government offices (PWD, Town planning, housing board etc) and local governance. Above all every individual should take personal responsibility for the space he uses, either at home, work place or a public space to safeguard his/ her personal health as it is believed that the indoor air is five times more polluted than the external air.

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