Air Pollution

Abstract

Air pollution is a major concern of new civilized world, which has a serious toxicological impact on human health and the environment. It has a number of different emission sources, but motor vehicles and industrial processes contribute the major part of air pollution. According to the World Health Organization, six major air pollutants include particle pollution, ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead. Long and short term exposure to air suspended toxicants has a different toxicological impact on human including respiratory and cardiovascular diseases, neuropsychiatric complications, the eyes irritation, skin diseases, and long-term chronic diseases such as cancer. Several reports have revealed the direct association between exposure to the poor air quality and increasing rate of morbidity and mortality mostly due to cardiovascular and respiratory diseases. Air pollution is considered as the major environmental risk factor in the incidence and progression of some diseases such as asthma, lung cancer, ventricular hypertrophy, Alzheimer's and Parkinson's diseases, psychological complications, autism, retinopathy, fetal growth, and low birth weight. In this review article, we aimed to discuss toxicology of major air pollutants, sources of emission, and their impact on human health. We have also proposed practical measures to reduce air pollution in Iran.

Keywords: Air pollution, cardiovascular diseases, environment, human health, respiratory tract diseases, toxicology

INTRODUCTION

Air pollution is a major problem of recent decades, which has a serious toxicological impact on human health and the environment. The sources of pollution vary from small unit of cigarettes and natural sources such as volcanic activities to large volume of emission from motor engines of automobiles and industrial activities.[1,2] Long-term effects of air pollution on the onset of diseases such as respiratory infections and inflammations, cardiovascular dysfunctions, and cancer is widely accepted;[3,4,5,6] hence, air pollution is linked with millions of death globally each year.[7,8,9] A recent study has revealed the association between male infertility and air pollution.[10]

Air pollution has now emerged in developing countries as a result of industrial activities and also increase the quantity of emission sources such as inappropriate vehicles.[11,12,13] About 4.3 million people die from household air pollution and 3.7 million from ambient air pollution, most of whom (3.3 and 2.6 million, respectively) live in Asia.[14] In Iran, as a developing country, the level of air pollutants has increased gradually since the beginning of industrialization in the 1970s, but it has reached a very harmful level in some megacities such as Tehran, Mashhad, Tabriz, Isfahan, Ahvaz, Arak, and Karaj over the past two decades. Iran is the world's third main polluted country in the world, which results in 16 billion $ annual loss.[15] In fact, four of the top ten air-polluted cities are in Iran. Ahvaz is the most air polluted city in the world with microdust blowing in from neighboring countries, and particulate levels three times that of Beijing, and nearly 13 times that of London.[16] Air pollution caused almost 4460 deaths in 2013 only in Tehran although the reality seemed higher and is getting worse every year.[17] Therefore, it is of great importance to describe the problem, particularly its toxic effects on human health and provide recommendations as a basis for environmental guidelines and standard protocols in the field of air pollution in Iran.

The present article is neither a systematic review nor a descriptive, educational study. It is a problem-based descriptive review in which the authors try to explain a problem which is the major health and ecological problem in