Central Pollution Control Board Report

A frequently asked question is whether the adverse health effects of air pollution are reversible, and whether staying in a cleaner environment for at least a few hours in a day has any beneficial effects on respiratory health. To address these questions, the health data of persons employed at Paharpur Business Centre (PBC), Nehru Place, New Delhi was compared with that of office employees elsewhere in Delhi. PBC provides office facilities and air consultancy services to various corporate and multinational companies. Since 1996, the indoor air quality (IAQ) at PBC has been maintained to conform to the standards for indoor air quality laid down by the American Society for Housing, Refrigeration, and Air-conditioning Engineers (ASHRAE).

PBC follows an eco-friendly approach to maintain a high level of IAQ. Outside air is washed with water in a scrubber before it is allowed inside the building, to reduce the level of water-soluble components like SO₂, NO₂ and SPM. The washed air is then passed through a green house of selected plants that effectively remove formaldehyde, benzene and carbon monoxide from the air and enrich it with freshoxygen(Fig. 9.1). The processed air is passed through micro-V filter to remove bacteria and pumped into the building as fresh air. The entire building is a no-smoking zone, which is strictly maintained. There are several offices in the building and a number of people work there for 8-10 hours per day. In this study the answer was sought to the question whether staying in a much cleaner environment for a substantial duration had any beneficial effect on their respiratory health.

Materials and Methods

A total number of 94 subjects working at Paharpur Business Center (PBC), male 61 and female 33 who were life time non smokers were enrolled. The participants were aged between 24 and 56 years with a median of 39 years (Fig. 9.2). Prevalence of respiratory symptoms and lung function impairment was evaluated by questionnaire survey and spirometry respectively. The findings were compared with Delhi's other office workers who were never smokers (n=1382, median age 42 year).

Results

It is evident from the table that indoor air of PBC had low pollutant levels during 2002-2003

The prevalence value of both URS and LRS in recent past (3 months) was significantly lower (p ‹ 0.05) among subjects employed at PBC than in the rest of the city. Compared with URS, the change was more noticable for LRS. Similarly, the prevalence of headache and eye irritation was significantly less (p ‹ 0.05) in persons employed at PBC. However, there was no change in the prevalence of asthama between these two groups.

Lung function was reduced in 23.4% employees of PBC compared with 35.4% of non-smoking employees of the city. Thus, there was 34% decline in the percentage of individuals with lung function deficits in PBC. In general, 27.4% non-smoking residents of South Delhi was found, where PBC was located, had lung function deficits. Prevalence among PBC employees was even lower than that, although a large section of PBC employees travel from other parts of the city. Besides lesser percentage of subjects with deficit lung function, the magnitude of deficit was much less among PBC employees as severe reduction in lung function was present in 3.2% employees against Delhi's average of 5.5% among office employees. Likewise, PBC employees had lower prevalence of COPD than city's average. Therefore, stay in a clear environment for 8-10 hours a day appeared to have beneficial effects on lung function.

Sputum cytology of persons employed at PBC showed 19% lesser number of cells, and 30-33% lower number of alveolar macrophages, siderophages and metaplastic squamous epithelial cells. The findings imply reduced exposure to particulates and a lower risk of microscopic hemorrhage in lung among PBC employees. Similarly, PBC employees had 36% lower micronucleus count and lower prevalence of hypertension, suggesting diminished risk of genotoxicity and cardiovascular diseases.

Inference

The study has demonstrated that the stay in a cleaner environment for 8-10 hours a day reduces the prevalence and magnitude of health impairments associated with chronic exposure to air pollution.

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