![]() | The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject.(August 2019) |
The health of a mother directly affects the fetus during pregnancy. High levels of vehicle pollution where pregnant women reside can have adverse health effects on fetuses.
In the United States about 10% of the population, 33 million people, live within 900 meters of a high traffic road [1] High-traffic roads are commonly identified as being host to more than 50,000 vehicles per day, which is a source of toxic vehicle pollutants. [2] Previous studies have found correlations between exposure to vehicle pollutants and certain diseases such as asthma, lung and heart disease, and cancer among others. Car pollutants include carbon monoxide, nitrogen oxides, particulate matter (fine dusts and soot), and toxic air pollutants [3] While these pollutants affect the general health of populations, they are known to also have specific adverse effects on expectant mothers, their fetuses and children. The purpose of this article is to outline how vehicular pollutants affect the health of expectant mothers and the adverse health effects these exposure have on the adult.
Areas with high levels of nitrogen dioxide in the air, which is an output of vehicular air-pollution, are shown to have negative effects on fetuses. Effects of the exposure include reduced fetal growth, premature birth, and respiratory conditions. Two studies were conducted to evaluate the effects of nitrogen dioxide on fetuses in the southern United States as well as Valencia Spain. In the United States, babies that were born prematurely were 94% more likely to have been exposed to high levels of pollution than those that were not premature. In Spain, fetuses that were small for gestational age in terms of weight were 37% more likely to have been exposed to high levels of air pollution than those that were not small for gestational age in terms of weight. [4] [5]
In Los Angeles County, researchers found a higher risk in premature birth (10-20%) and low birth weight for infants whose mothers lived near high traffic areas [6] Studies conducted on populations living near the 405 and 710 interstates in Southern California found their exposure to particulate vehicle emissions to be almost 25 times higher than for people living 1000 ft from the freeways. This research also concluded that particulate vehicle emissions are more toxic to children's health than other particles such as Carbon Monoxide and Nitrogen Dioxide [7] [8]
Carbon monoxide (CO) is directly released from motor vehicles engines, which are a major source of this pollutant in the LA Basin [8] 5. CO inhaled by pregnant women may threaten the unborn child's growth and mental development. Because CO competes with Oxygen to achieve dispersion throughout the blood stream, fetal hypoxia (lack of oxygen) may result at high levels of maternal CO exposure, however the exact amount of exposure of CO to become a fetal threat is unknown [9] High levels of carbon monoxide are also found in cigarettes, it is advised that pregnant women avoid smoking so as to not run the risk of affecting their child's growth or mental development. For further information on Carbon Monoxide and its effects on human health please see, Carbon monoxide poisoning.
Nitrogen oxides (NO) are common air pollutants found throughout most of the United States. You can be exposed to these oxides by breathing polluted air, which is most commonly found in areas with heavy motor vehicle traffic [10] Exposure to high levels of Nitrogen oxides damages tissues of the throat and upper respiratory tract and can interfere with the body's ability to carry oxygen. High exposure to nitrogen dioxide may cause fetal mutations, damage a developing fetus, and decrease a woman's ability to become pregnant. Studies have also shown that higher exposures to NO inhibit embryo development during both traditional pregnancies and artificial inseminations [11] [12]
Examples of particulate matter include ash from smoke in campfires, dust particles around your house, and smoke coming from car exhaust pipes; in areas close to freeways this is a problem. A study conducted on European women indicated that higher exposure to particulate matter during the initial first weeks of their pregnancy resulted in low birth weight babies [13] This toxin is also considered to be the most dangerous of the three because it can be basically anything small enough to be inhaled. This may also be due to the fact that brain growth begins within the first month of conception.
A previous study conducted in the Los Angeles Basin of Southern California reported a consistent association between levels of CO and particulate matter during the first trimester and the last six weeks prior to birth and risk of preterm birth. Prematurity in babies is accompanied by an array of health complications. Children born prematurely are at highest risk for developing Infant respiratory distress syndrome, gastrointestinal, and hematologic diseases, central nervous system (CNS) problems such as hearing loss, are more prone to infections, and at risk for hearing and vision loss.
Babies born of low weight are also at risk for respiratory, gastrointestinal, cardiac, CNS, infection and vision problems. These gestational issues persist until the adult years for most children and result in high blood pressure, Type II Diabetes, and other heart diseases.
Prematurity and Low Birth Weight caused by air pollution also affects fetal brain development. This is of importance since lack of proper brain development will not allow a child's brain to form proper synapse connections which will negatively affect the child's speech, learning abilities, and social skills.
Exposure to air pollution not only affects newborns in early stages of their development, it can also have lifelong consequences for children exposed from the time of conception to when they reach two years of age. Air pollution has been found to cause lower birth weights, insufficient development of the immune system and organs, and premature births. These birth effects have been linked to respiratory issues that can persist into one's long-term health. [14]
Exposure to vehicle air pollutants has been noted as primary cause for infant mortality and morbidity, and is also argued to be a cause of chronic diseases such as asthma in child and adulthood [15]
The number of children affected by asthma has increased in past decades the point where it is now the most chronic illness in children and the most common cause of children hospitalizations in the U.S. causing it to also be a number one contributor to school absences [16] Excessive school absences ultimately affect the child's learning ability, and decrease their time to socialize with kids their age. It is not uncommon for children who suffer from asthma to oftentimes repeat grades due to failure to keep up academically. If students are not repeating grades they are highly likely to dropout prior to graduation over their non-affected peers. [17]
Studies have found that children who are exposed to higher levels of car pollutants report higher respiratory problems including wheezing, ear and throat infections and have a higher incidence of physician-diagnosed asthma. [18] [19] Bronchiolitis is also found in greater amounts when the child's home is around high amounts of traffic. [20]
Children living in close proximity to high traffic areas are also eight times more likely to develop leukemia compared to children who do not [21] This finding indicates that children who develop cancer as a result of traffic exposure will also spend more time in the hospital. This is not only a cause of school absences, but also a time of trauma for a child who is constantly visiting providers for treatment. Children with cancer have a harder time keeping up with school and keeping up with their friends [22]
Autism is a spectrum of disorders that range from a severe inability to communicate and some mental disabilities to milder symptoms such as attention disorders. Some claims exist that the incidence of autism is higher for babies whose mothers spend time in ‘high traffic pollution’ areas compared to mothers who spend their pregnancy in cleaner air. In a recent study conducted by UCLA, air pollutant levels were measured for mothers who had children with autism and then compared to air pollutant levels in environments for mothers who had children without autism. This study found that babies who were exposed to higher levels of pollutants while in the womb had a 10% higher risk of autism than babies who had low levels of exposure; another finding from this study is that fine particulates had the strongest association with autism [23]
Motor vehicle emissions are not solely a United States issue. Of the 10 cities with the most traffic, there are no cities from the United States listed. [24] The United States also has regulations regarding what and how many emissions vehicles are allowed to emit that are on the road. This is done by the USEPA and they are currently working on new regulations. [25] Of the countries that have vehicle emission standards, the European Union and Japan have the most strict regulations. These standards have been added because it is shown that regulating fuel economy is effective in controlling oil demands for the country as well as reducing their greenhouse emissions. [26]
Respiratory and allergic disorders among children in Japan were studied after the implementation of new regulations were put in place and it showed the prevalence of asthma and other respiratory disorders decreased. [27] There have also been more recent studies showing that the incidence of asthma cases worldwide is increasing in children. Much of this increase is due to the increase in NO2 which is a gas that is emitted from motor vehicles among other sources. [28]
Across the United States, vehicle emissions make up a large portion of air pollution, especially in urban areas. An epidemiological study conducted by the National Institute of Health compared pregnancy loss to local vehicle emissions, specifically nitrogen dioxide (NO₂). The study used data from Boston, Massachusetts and Tel Aviv, Israel, and both regions observed associations between pregnancy loss and NO₂, largely in the second trimester of pregnancies. This study further increases scientific confidence that vehicle emissions can be detrimental to pregnant individuals and fetuses and that these findings are consistent in different geographic locations and among different populations. [29]
Smog, or smoke fog, is a type of intense air pollution. The word "smog" was coined in the early 20th century, and is a portmanteau of the words smoke and fog to refer to smoky fog due to its opacity, and odor. The word was then intended to refer to what was sometimes known as pea soup fog, a familiar and serious problem in London from the 19th century to the mid-20th century, where it was commonly known as a London particular or London fog. This kind of visible air pollution is composed of nitrogen oxides, sulfur oxide, ozone, smoke and other particulates. Man-made smog is derived from coal combustion emissions, vehicular emissions, industrial emissions, forest and agricultural fires and photochemical reactions of these emissions.
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline (petrol), diesel fuel, fuel oil, biodiesel blends, or coal. According to the type of engine, it is discharged into the atmosphere through an exhaust pipe, flue gas stack, or propelling nozzle. It often disperses downwind in a pattern called an exhaust plume.
Air pollution is a concern in British Columbia, Canada because of its effects on health and visibility. Air quality is influenced in British Columbia (BC) by numerous mountain ranges and valleys, which complicate atmospheric pollution dispersion and can lead to high concentrations of pollutants such as particulate matter from wood smoke.
Diesel exhaust is the gaseous exhaust produced by a diesel type of internal combustion engine, plus any contained particulates. Its composition may vary with the fuel type or rate of consumption, or speed of engine operation, and whether the engine is in an on-road vehicle, farm vehicle, locomotive, marine vessel, or stationary generator or other application.
Environmental toxicants and fetal development is the impact of different toxic substances from the environment on the development of the fetus. This article deals with potential adverse effects of environmental toxicants on the prenatal development of both the embryo or fetus, as well as pregnancy complications. The human embryo or fetus is relatively susceptible to impact from adverse conditions within the mother's environment. Substandard fetal conditions often cause various degrees of developmental delays, both physical and mental, for the growing baby. Although some variables do occur as a result of genetic conditions pertaining to the father, a great many are directly brought about from environmental toxins that the mother is exposed to.
Low birth weight (LBW) is defined by the World Health Organization as a birth weight of an infant of 2,499 g or less, regardless of gestational age. Infants born with LBW have added health risks which require close management, often in a neonatal intensive care unit (NICU). They are also at increased risk for long-term health conditions which require follow-up over time.
Air pollution is the contamination of air due to the presence of substances called pollutants in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. It is also the contamination of the indoor or outdoor environment either by chemical, physical, or biological agents that alters the natural features of the atmosphere. There are many different types of air pollutants, such as gases, particulates, and biological molecules. Air pollution can cause diseases, allergies, and even death to humans; it can also cause harm to other living organisms such as animals and crops, and may damage the natural environment or built environment. Air pollution can be caused by both human activities and natural phenomena.
Household air pollution (HAP) is a significant form of indoor air pollution mostly relating to cooking and heating methods used in developing countries. Since much of the cooking is carried out with biomass fuel, in the form of wood, charcoal, dung, and crop residue, in indoor environments that lack proper ventilation, millions of people, primarily women and children face serious health risks. In total, about three billion people in developing countries are affected by this problem. The World Health Organization (WHO) estimates that cooking-related pollution causes 3.8 million annual deaths. The Global Burden of Disease study estimated the number of deaths in 2017 at 1.6 million. The problem is closely related to energy poverty and cooking.
Air pollution is the introduction of chemicals, particulate matter, or biological materials into the atmosphere, causing harm or discomfort to humans or other living organisms, or damaging ecosystems. Air pollution can cause health problems including, but not limited to, infections, behavioral changes, cancer, organ failure, and premature death. These health effects are not equally distributed across the U.S. population; there are demographic disparities by race, ethnicity, socioeconomic status, and education. Air pollution can derive from natural sources, or anthropogenic sources. Anthropogenic air pollution has affected the United States since the beginning of the Industrial Revolution.
Pollution in California relates to the degree of pollution in the air, water, and land of the U.S. state of California. Pollution is defined as the addition of any substance or any form of energy to the environment at a faster rate than it can be dispersed, diluted, decomposed, recycled, or stored in some harmless form. The combination of three main factors is the cause of notable unhealthy levels of air pollution in California: the activities of over 39 million people, a mountainous terrain that traps pollution, and a warm climate that helps form ozone and other pollutants. Eight of the ten cities in the US with the highest year-round concentration of particulate matter between 2013 and 2015 were in California, and seven out of the ten cities in the US with the worst ozone pollution were also in California. Studies show that pollutants prevalent in California are linked to several health issues, including asthma, lung cancer, birth complications, and premature death. In 2016, Bakersfield, California recorded the highest level of airborne pollutants of any city in the United States.
Asthma is a common pulmonary condition defined by chronic inflammation of respiratory tubes, tightening of respiratory smooth muscle, and episodes of bronchoconstriction. The Centers for Disease Control and Prevention estimate that 1 in 11 children and 1 in 12 adults have asthma in the United States of America. According to the World Health Organization, asthma affects 235 million people worldwide. There are two major categories of asthma: allergic and non-allergic. The focus of this article will be allergic asthma. In both cases, bronchoconstriction is prominent.
Air Pollution in Mexico City has been of concern to the city's population and health officials for decades. In the 20th century, Mexico City's population rapidly increased as industrialization brought thousands of migrants from all over the world. Such a rapid and unexpected growth led to the UN declaring Mexico City as the most polluted city in the world in 1992. This was partly due to Mexico City's high altitude, which causes its oxygen levels to be 25% lower. Carbon-based fuels also do not combust completely. Other factors include the proliferation of vehicles, rapid industrial growth, and the population boom. The Mexican government has several active plans to reduce emission levels which require citizen participation, vehicular restrictions, increase of green areas, and expanded bicycle accessibility.
Air pollution is the release of pollutants into the air that are detrimental to human health and the Earth. In Canada, air pollution is regulated by standards set by the Canadian Council of Ministers of the Environment (CCME), an inter-governmental body of federal, provincial and territorial Ministers responsible for the environment. Air pollution from the United States and to lesser extent Canada; caused by metal smelting, coal-burning for utilities, and vehicle emissions has resulted in acid rain, has severely impacted Canadian waterways, forest growth, and agricultural productivity.
Particulates or atmospheric particulate matter are microscopic particles of solid or liquid matter suspended in the air. The term aerosol commonly refers to the particulate/air mixture, as opposed to the particulate matter alone. Sources of particulate matter can be natural or anthropogenic. They have impacts on climate and precipitation that adversely affect human health, in ways additional to direct inhalation.
The Air Quality Health Index (AQHI) is a scale designed in Canada to help understand the impact of air quality on health. It is a health protection tool used to make decisions to reduce short-term exposure to air pollution by adjusting activity levels during increased levels of air pollution. The Air Quality Health Index also provides advice on how to improve air quality by proposing behavioral change to reduce the environmental footprint. This index pays particular attention to people who are sensitive to air pollution. It provides them with advice on how to protect their health during air quality levels associated with low, moderate, high and very high health risks.
Air pollution in India is a serious environmental issue. Of the 30 most polluted cities in the world, 21 were in India in 2019. As per a study based on 2016 data, at least 140 million people in India breathe air that is 10 times or more over the WHO safe limit and 13 of the world's 20 cities with the highest annual levels of air pollution are in India. 51% of the pollution is caused by industrial pollution, 27% by vehicles, 17% by crop burning and 5% by other sources. Air pollution contributes to the premature deaths of 2 million Indians every year. Emissions come from vehicles and industry, whereas in rural areas, much of the pollution stems from biomass burning for cooking and keeping warm. In autumn and spring months, large scale crop residue burning in agriculture fields – a cheaper alternative to mechanical tilling – is a major source of smoke, smog and particulate pollution. India has a low per capita emissions of greenhouse gases but the country as a whole is the third largest greenhouse gas producer after China and the United States. A 2013 study on non-smokers has found that Indians have 30% weaker lung function than Europeans.
Toxic hotspots are locations where emissions from specific sources such as water or air pollution may expose local populations to elevated health risks, such as cancer. These emissions contribute to cumulative health risks of emissions from other sources nearby. Urban, highly populated areas around pollutant emitters such as old factories and waste storage sites are often toxic hotspots.
Nitrogen dioxide poisoning is the illness resulting from the toxic effect of nitrogen dioxide. It usually occurs after the inhalation of the gas beyond the threshold limit value. Nitrogen dioxide is reddish-brown with a very harsh smell at high concentrations, at lower concentrations it is colorless but may still have a harsh odour. Nitrogen dioxide poisoning depends on the duration, frequency, and intensity of exposure.
Environmental health policy is governmental action intended to prevent exposure to environmental hazards or "eliminate the effects of exposure to environmental hazards".
Particulate pollution is pollution of an environment that consists of particles suspended in some medium. There are three primary forms: atmospheric particulate matter, marine debris, and space debris. Some particles are released directly from a specific source, while others form in chemical reactions in the atmosphere. Particulate pollution can be derived from either natural sources or anthropogenic processes.