Sharma, Mandakini; Pal, Brijesh; Pal, Anil and Bajpai, A. B.
Hazardous chemicals escape to the environment by a number of natural and/or anthropogenic activities and may cause adverse effects on human health and the environment. Increased combustion of fossil fuels in the last century is responsible for the progressive change in the atmospheric composition. Air pollutants, such as carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxides (NOx), volatile organic compounds (VOCs), ozone (O3), heavy metals, and respirable particulate matter (PM2.5 and PM10), differ in their chemical composition, reaction properties, emission, time of disintegration and ability to diffuse in long or short distances. Air pollution has both acute and chronic effects on human health, affecting a number of different systems and organs. It ranges from minor upper respiratory irritation to chronic respiratory and heart disease, lung cancer, acute respiratory infections in children and chronic bronchitis in adults, aggravating pre-existing heart and lung disease, or asthmatic attacks. In addition, short- and long-term exposures have also been linked with premature mortality and reduced life expectancy. These effects of air pollutants on human health and their mechanism of action are briefly discussed.
Keywords: Air pollutant | Human health | Cellular actions | Detoxification
Introduction
The study of air pollution in geography requires spatio-temporal scientific analysis. Geographical study of air pollution in Dehradun city area takes into account the impact of various pollutants in the atmosphere in spatio-temporal context (Singh, 1988, 1992). It also examines the effect of pollutants on human health as well as on plants and animals in the study area. Many of the research work has been undertaken on different aspects of air pollution in the field of geography but significant work with an impact on human health has been conducted in this area by analyzing the spatial pattern of air pollution, air quality and its impact through this study. Thus the air pollution is defined as the presence of any solid, liquid or gaseous substance present in atmosphere in such concentration as may be or tends to be injurious to human beings or other living creatures or plants or property or environment.
Air quality in the Indian cities is deteriorating due to rapid and unplanned developmental processes (Singh et al 2007; Gupta et al. 2009). After the creation of a new state Uttarakhand, in the year 2000, most of the cities of the state, especially Dehradun the capital city, suffered tremendous pressure of increasing population accompanied with the rapid increase in the number of vehicles. Air quality status in Dehradun city revealed that SO2 and NOx concentrations are under prescribed limit of CPCB, but SPM and RSPM exceed the limit (Chauhan et al. 2010). In comparison with the earlier years 2004 and 2006, air pollution as indicated by similar lichen shows a considerable increase in the total metal concentration (especially Pb) in the ambient air of Dehradun city, which may be attributed to exponential rise in the traffic activity in the last 5 years.