When we think of air pollution, we are most likely to think of hundreds of cars in a traffic jam, giant industrial chimneys and cities blinded by heavy smog. However, we are not often aware that the air quality in our homes can sometimes be worse than the air quality outside. According to the United States Environmental Protection Agency (EPA), the levels of indoor air pollutants are usually 2 to 5 times higher than outdoor levels, and can go upto 100 times of the same pollutants compared to outside.
How is indoor air pollution different?
The air that occupies our living rooms, bedrooms, offices, closed public places, and interiors of a public transport are often contaminated by pollutants such as Volatile Organic Compounds (VOCs), combustion byproducts (Carbon Monoxide, Indoor Particulate matter, Secondhand smoke and smoke from cookstoves and heaters) and biological pollutants. On the other hand, outdoor air pollution are emissions caused by motor vehicles and factories, and natural sources such as smoke from wildfires, windblown dust, and biogenic emissions from vegetation (pollen and mold spores).
Since we humans spend a large amount of time indoors for both work and leisure, poor indoor air quality can easily impact our lungs, heart and induce various illnesses. Since the spread of the COVID-19, it has become even more important that we pay attention to the quality of our indoor air because as we now see how easily air-borne pathogens can spread from one member of the household to another. This also affects business and the wider economy as closed office spaces and factory units with poor indoor air quality become a hotspot for the spread of the virus.
Outdoor Air Pollution also affects Indoor Air Quality
Our homes are not traditionally designed to protect us from outdoor air pollution. Since we spend most of our time indoors and frequently at home, exposure to air pollution is also a constant worry. Infiltration of outdoor air pollutants is a significant cause of air pollution in homes, in addition to indoor emissions from activities like cooking and cleaning. Open windows and doors, supply air ventilation systems and other openings allow outdoor air pollution to enter buildings as a result of wind pressure and temperature changes.
Measuring Outdoor Air Quality
The Air Quality Index (AQI) is used to measure outdoor air quality. The AQI has a yardstick that runs from 0 to 500. The higher the AQI value, the greater the level of air pollution and the greater the health concern. For example, an AQI value of 40 or below represents good air quality, while an AQI value over 250 represents poor air quality.
Different countries have their own air quality indices, according to different national air quality standards. In India, the AQI considers eight pollutants: PM10 (Particulate matter 10), PM2.5 (Particulate matter 2.5), NO2 (Nitrogen Dioxide), SO2 (Sulfur Dioxide), CO (Carbon Monoxide), O3 (Ozone), NH3 (Ammonia) and Pb (Lead).
Measuring Indoor Air Quality
Indoor Air Quality (IAQ) is measured and monitored by taking into consideration factors such as the presence of carbon dioxide, particulate matter concentrations (PM 2.5 and PM 10), chemical pollution (VOCs) concentrations and humidity. Portable sensors are deployed in the rooms for a few hours. These are equipped with technology to detect the presence of various pollutants in the air. After the indoor air quality test, the user receives a detailed report citing levels of indoor air pollutants in easy-to-understand terms. The experts can also offer consultations and recommendations based on the air quality evaluation report.
Overcoming Indoor and Outdoor Air Pollution
It is difficult to overcome the challenge of outdoor air pollution without effective public policy. Government bodies as well as private ventures need to come together for innovative and cost-effective solutions. Improving and promoting use of public transport, transitioning to green energy, regulated construction activities and consistent real-time air monitoring and analysis of air pollution data are some important steps.
Indoor air quality, on the other hand, requires high performance ventilation and air filtration technology along with regular air quality tests or monitoring. Commonly three types of air filters are available in the market - Pre Filters, HEPA Filters and Carbon Filters. HEPA filters are most preferred as they trap the smallest pollutants in indoor air.
It is important to note that concentration of pollutants indoors varies from house to house even if they are within the same neighborhood. This is because of different lifestyles, ventilation provisions, cleaning chemicals used or cooking activities. Understanding Indoor air pollution is complicated and solutions are never one-size-fits-all. We should treat Indoor Air Quality tests as timely health checkups for homes. Just like we think twice about the quality of food or water we introduce into our bodies, we must also take the quality of air we breathe much more seriously.