Air Pollution In Ahwaz, Iran: Understanding The Main Causes

Ahvaz, the capital of Iran's Khuzestan province, is one of the most polluted cities in the world. The city's poor air quality has been attributed to various factors, including dust storms, industrial activities, and emissions from major industries such as steel and oil. The high concentration of airborne particles, including PM2.5 and PM10, has severe health implications for residents, exacerbating respiratory and cardiovascular issues and contributing to climate change. Ahvaz's air pollution has been a focus of scientific studies and public health concerns, with an emphasis on identifying sources and implementing effective solutions.

Dust storms

Ahvaz, the capital of Khuzestan province in Iran, has been affected by dust storms in recent years. These dust storms are one of the main natural hazards that have impacted the region, causing various social, economic, and health issues.

The dust storms in Ahvaz are associated with specific synoptic systems, including summer and winter Shamal, cyclonic, and pre-frontal systems. These systems can transport a significant amount of dust into the city from various sources, such as the Aljazeera desert, the Alluvial Plain, the Mesopotamian marshlands, Zubair, the Ad Dahna Desert, and the arid Khuzestan Plain.

The deserts in neighbouring countries, such as Iraq, Saudi Arabia, and Kuwait, also contribute significantly to the dust storms in Ahvaz. According to studies, these countries account for 32%, 26%, and 16% of the dust plumes transported over the city, respectively. Additionally, the HYSPLIT model has been used to study the origins and trajectories of dust storms affecting Ahvaz, indicating that dust particles can arrive from different directions, including northwestern Iraq and eastern Syria or central Iraq to western Iran.

The dust storms in Ahvaz have severe health implications for residents. Particulate matter smaller than 10 micrometers (PM10) is of particular concern, as it can cause respiratory infections, decreased lung function, and exacerbate asthma symptoms. The ionic and chemical composition of these particles during dust storms can have toxicological impacts on lung cells and cause other health issues.

To better understand the challenges faced by the residents of Ahvaz, a qualitative study was conducted to assess the perceptions and lived experiences of individuals during sand and dust storms (SDSs). This study highlighted the direct and indirect impacts of SDSs on human health, the environment, the economy, and urban life in the affected regions.

Industrial pollutants

The Khouzestan Steel Company, for example, has been identified as a source of emissions and industrial pollutants in Ahvaz. The concentration of PM2.5, which are fine particulate pollutants, in the city has been measured at levels 6.3 times higher than the World Health Organization's annual guideline value. These fine particles can be inhaled deep into the lungs and cause serious health issues, including respiratory problems and decreased lung function.

In addition to the steel industry, the oil industry also plays a significant role in Ahvaz's air pollution. The city is located in a region that has become a centre for oil and gas exploration, with vast areas seized for refineries and pipelines. The consumption of fuel energy, along with oil and petrochemical industries, are major contributors to the city's pollution levels.

Ahvaz's proximity to Iraq and its position as a border to the Khuzestan province further exacerbates the issue. The region has experienced dust storms, a natural hazard that has impacted the air quality and public health. These storms, along with the industrial emissions, have led to a situation where the air is unsafe to breathe, causing respiratory issues and other health problems for the residents.

The Iranian government has faced criticism and protests from residents demanding better management and addressing of the environmental degradation and air pollution in the region. International sanctions against Iran have also played a role, as they have led to the production of sub-standard gasoline and a lack of emission control equipment in vehicles, further contributing to the air pollution in Ahvaz.

Major industries: steel, oil, drilling, and oil extraction

Ahvaz, the capital of the Khuzestan province in Iran, has been facing a severe air pollution problem. The city's air quality has deteriorated to levels that are unsafe to breathe, causing respiratory issues and other health problems for residents.

Major industries, including steel, oil, drilling, and oil extraction, are significant contributors to the poor air quality in Ahvaz. The presence of these heavy industries, along with oil and gas exploration, has turned the region into a heavily polluted area. The Khouzestan Steel Company, in particular, has been identified as a source of emissions.

In addition to the industrial activities, the consumption of fuel energy and the presence of oil and petrochemical industries also play a role in the city's air pollution. The use of sub-standard gasoline, due to international sanctions, and the abundance of old vehicles that do not meet modern emission regulations further exacerbate the problem.

The impact of air pollution on the health of Ahvaz's residents has been a growing concern. The rate of respiratory problems has increased sharply, and the city experienced a respiratory health crisis in 2011, which repeated in subsequent years. The high levels of air pollution have also led to the suspension of flights and the temporary closure of schools in the city.

Microplastics

Ahvaz, Iran, is known for its high levels of air pollution. While studies have primarily focused on the effects of air pollution on total deaths, there has been limited research on the effects of individual factors such as age and gender. In 2011, the World Health Organization declared Ahvaz the most polluted city in the world, based on the annual average of PM10 (particulate matter smaller than 10 micrometers).

In Ahvaz, studies have investigated the concentration, distribution, fate, and chemical composition of MPs in both urban and industrial soils. MPs were found in various shapes, colours, and sizes, with microfibres being the most abundant. The concentration of MPs in urban soils ranged from 100 to 3135 unit·kg−1, while in industrial soils, it ranged from 80 to 1220 unit·kg−1. The most contaminated urban sites were in the city centre, where insufficient sanitation infrastructure, including sewer systems and sewage treatment, contributed to the high levels of pollution.

MPs can enter the environment through various sources, including municipal wastewater treatment plants and urban landfills. While MPs can persist in the environment due to their inert nature, physical weathering, photo-oxidation, and slow biological decomposition can break them down into smaller particles, known as nanoplastics.

The presence of MPs in the atmosphere of Ahvaz has also been studied, with sample characteristics and trajectory modelling suggesting both local and long-range sources. MPs in the atmosphere can pose health risks to humans, as they can be inhaled and deposited in the lungs, leading to inflammation and other adverse effects.

To address the issue of MP pollution, it is crucial to reduce the usage of single-use plastics and implement effective policies and regulations. Biodegradable materials and efficient air-filtration systems can also play a role in mitigating the impact of MPs on the environment and human health.

Air quality classed as unhealthy for sensitive groups

Air quality classed as "unhealthy for sensitive groups" means that the air quality is OK for the general public, but certain vulnerable groups may face an elevated health risk and should take caution while outdoors. This includes children, older adults, people with heart or lung disease, people with diabetes, and people of lower socioeconomic status. These groups are more susceptible to the health effects of air pollution due to factors such as developing lungs, higher breath rates relative to body weight, and pre-existing health conditions.

In the context of Ahwaz, Iran, the air quality in the city and the surrounding Khuzestan province has been described as "extremely dangerous". This situation has led to the suspension of flights and the temporary closure of schools. The main causes of air pollution in Ahwaz include emissions from heavy industries, oil and gas exploration, refineries, and pipelines, as well as traffic from old cars that do not meet current emission regulations.

To protect themselves from the harmful effects of air pollution, sensitive groups should follow recommendations such as staying indoors, closing doors and windows, wearing masks when going outside, and reducing the amount of time spent on outdoor activities, especially those involving heavy physical exertion. Real-time air quality information and forecasts are available through various sources, such as the Air Quality Index (AQI) and apps like AirNow, which can help individuals plan their activities and take necessary precautions.

The definition of "sensitive groups" in the context of air quality extends beyond those with pre-existing health conditions. It also includes healthy adults who spend significant amounts of time outdoors, as their higher exposure rates put them at a greater risk of experiencing the negative health effects of air pollution.

The AQI uses colour-coded categories to communicate the level of health risk associated with the current air quality. For example, a yellow level (AQI values of 51-100) indicates that the air quality is acceptable for the general public but may pose risks to sensitive groups. An orange level (AQI values of 101-150) suggests that sensitive populations may experience health effects and should limit their time outdoors. A "code red" day (AQI values of 151-200) is considered unhealthy for everyone, and sensitive groups may experience more severe health impacts.

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