Indoor Air Pollution and the Microatmosphere

VOCs can present special problems in the indoor microatmosphere. A common source of such emissions consists of oil-based paints from which the volatile paint vehicles evaporate as the paint dries. Water-based latex paints even have the potential to emit air pollutants. One such source consists of coalescents added to these paints that enable the colloidal particles in the paint to spread, giving a uniform painted surface. A Presidential Green Chemistry Challenge award was given to 

Some of the most harmful indoor atmospheres are created in less developed regions where poorly ventilated open fires are used for cookiug. These may be iu regions where cooking fuel is scarce and wood, brush, and dried animal dung are used for fuel. 

As discussed in Section 7.2, radioactive radon anitted from the geosphere below dwellings can be a serious indoor air pollutant. In some areas where radon can be a problem, testing for this indoor air pollutant is required when a dwelling is sold, and it may be necessary to install ventilation facilities around the foundations of afflicted buildings. 

The workplace can often suffer from unhealthy indoor air quality due to emissions of materials as the result of activities in the workplace. In Chapter 6, Section 6.8, the unfortunate case was discussed of workers in Turkey who developed lung silicosis resulting from their sandblasting jeans to give them a distressed appearance. Because of emissions from primers and paints, the microatmospheres in auto body shops may contain high levels of VOCs and particles produced in spray painting. 

An important device for controlling indoor air pollutants is the HEPA (high-efficiency particulate air) air filtration system that removes at least 99.97% of particles greater than 0.3 pm in size from the air passing through the filtration system. Air pollutant molecules such as those of ozone, SO2, or NO2 are not removed by particle filtration, but may be reduced by reaction with the filter material and particulate matter held on the filtration system. 

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