Air pollution from ships or ports harboring a problem?
09 December 2021
16 January 2017
Ports have long been gateways for global trade and are critical to economies around the world. They are hubs of economic activity; they are also major sources of ship pollution, vehicle emissions, dust and noise. Ports are often close to heavily populated urban areas – which can mean exposing millions of inhabitants to additional pollution. As city environmental agencies look to improve air quality, air pollution from ships and ports stimulates control measures.
How do ships and ports contribute to air pollution?
Shipping vessels with engines run on heavy fuel oil. Heavy fuel oil is much cheaper than the petrol used in land transport, but it also has a high polluting impact. The SO2 content of Heavy Fuel Oil is 2700 times higher than road fuel! In developed countries SO2 emissions have been dropping so that now SO2 pollution is rare in urban environments. The main SO2 source remaining is from ships coming into port.
In addition to ships, ports contain a vast array of diesel powered machinery: straddle carriers, terminal tractors, reach lifters. Diesel powered engines result in elevated emission of various pollutants. They also make a lot of noise, another form of pollution. Added to the shipping emissions this makes ports a significant net contributor to pollution in large port cities.
Finally, ports handle large amounts of bulk materials e.g. aggregates, foodstuffs, fertilizer and wood products. These materials in dry and windy conditions inevitably result in dust drifting into neighboring areas. Dust, because it can be seen and felt by affected people, can be a major nuisance. These materials can often be smelly, which further upsets the neighbors.
This pollution causes an array of environmental impacts, can seriously affect the health of workers and contributes significantly to regional air pollution from ships and ports.
What pollutants are the problem?
Major air pollutants generated by port activities include carbon monoxide (CO), volatile organic compounds (VOCs), nitrogen oxides (NOx), sulfur oxides (SOx), and particulate matter (PM). The health effects of prolonged exposure to these compounds include respiratory diseases, cardiovascular disease, lung cancer and premature death.
A recent study found that emissions from diesel engines, commonly used in the freight industry, are significantly more harmful to humans than those from petrol vehicles and more than 30 human epidemiological studies have found that diesel exhaust exposure directly increases cancer risk. In addition to diesel exhaust, the negative health effects of exposure to inhalable particulate matter are also well documented. These tiny particles get into the lungs and are small enough to pass through tissues and enter the blood stream. They can then trigger inflammations which eventually cause heart and lung failures. The World Health Organisation estimates that long term exposure to PM2.5 is associated with an increase in the risk of cardiopulmonary mortality by 6–13% per 10 µg/m3 of PM2.5.
Understand the problem
Reducing air pollution from ships and ports is a top priority for many governments, however it can incur significant cost and is often politically challenging. So the first step is to quantify the problem and to fully understand the type and sources of pollution. To do that an air quality monitoring programme must be put into action.
Real time air quality monitoring in areas directly surrounding port operations is the most effective way to study the impact of port related emissions. Providing continuous real-time data, a network of air quality monitoring stations can be helpful to determine what days experience elevated levels of port generated pollution. Pollution data can also be combined with meteorological parameters to help identify those most affected by port operations and explain why some monitoring sites experience better or poorer air quality days. This allows port authorities to track historical trends in air pollution, quantify the effects of port related emissions and provide a benchmark for gauging the effectiveness of pollution reduction measures. It also allows government authorities to compare local air quality with state or national clean air standards.
Implementing your own port air quality monitoring programme?
Specific monitoring guidelines are usually prescribed by local body authorities and/or national environmental protection agencies. That said, the following criteria may help to provide some initial guidance for those looking to establish a port based air quality network.
An ideal sampling network will border port emissions sources on four sides. Networks of this structure provide opportunities for at least one air quality monitoring station to be impacted primarily by port emissions, regardless of wind direction. This design also provides the capacity for upwind/downwind analysis, such as during periods of onshore/offshore winds.
Monitoring sites should be protected from natural and human elements to ensure the security of the samplers and minimize the chance of vandalism. Ease of access is also essential for ensuring routine maintenance can be carried out easily. Additionally, choosing locations equipped with a mains power supply removes the need for batteries or solar panels, reduces the chance of power outages and helps to maintain data continuity. This is essential for compliance monitoring programs that require data capture rates above a certain percentage.
Consistency is critical to the overall success of monitoring programs and achieving high quality data capture. The best sampling locations will provide adequate and unobstructed exposure to port emissions sources and the surrounding environment. Air sampling inlets should be located at heights above the ground that are consistent between sampling locations and free from the effects of microscale climates created by wind shear from surrounding structures.
Locating samplers within communities neighbouring port activities, will allow for comparison with national ambient air quality standards.
Who is monitoring shipping pollution?
The following case studies give real life examples (taken from Aeroqual’s customer base) of how environmental managers are using air quality monitoring instruments to monitor shipping pollution.
Port of Townsville (Australia)
Located north of Brisbane on the east coast of Queensland, the Port of Townsville runs a bulk storage and handling terminal that is a gateway for trade and investment in the region. The Port operates two Aeroqual Dust Sentry’s that were chosen specifically because their highly portable design. These monitoring devices are taken up on top of large vessels to provide real-time PM10 measurements during loading and unloading operations. Both units are battery powered and set up to provide SMS alerts so that the Port Authority can take immediate action if pre-set air quality limits are exceeded.
Ridley Coal Terminals (Canada)
Ridley Coal runs a large bulk handling terminal on the West Coast of Canada, which is a vital link in the energy supply chain between North America and Asia. The terminal is located in a pristine Pacific Coast environment, close to the local community. Ridley operates two AQM 60s for measuring CO and PM10 and one Dust Sentry for measuring PM10. Both give alerts in real-time allowing Ridley to initiate control protocols in the event of elevated dust or CO levels.
Ganagavaram Port (Vizag, India)
Ganagavaram Port’s monitoring network gathers air quality data on a real-time basis to provide timely and accurate information on air quality in the Port area. The network consists of three Aeroqual Dust Profilers that are used to measure particulate matter (TSP, PM10, PM2.5 and PM1). Data collected from the air quality monitoring network is used to monitor the levels of coal dust generated by the loading and unloading of coal at Ganagavaram. The coal is initially unloaded into large piles on the docks before being loaded into rail cars or Lorries to be distributed across the country. The coal is also used to the neighboring Vizag Steel Plant.
How are some ports tackling poor air quality?
Once the air pollution from ships and ports problem has been quantified through an effective air quality monitoring programme, steps can be taken to reduce emissions. Shipping emissions are a major contributor to overall port pollution, and here are a few ways shipping pollution is being tackled.
Low Sulfur Fuels
Switching to low sulfur fuels is one of the easiest measures to reduce ship pollution. The suflur content of Heavy Fuel Oil (up to 35,000ppm) is almost 35 times that of low sulfur alternatives such as Marine Gas Oil (MGO), which only contains up to 1,000 ppm. In addition, using low sulfur fuels also reduces other pollutant emissions.
Using scrubbers can cut emissions of SO2 by 99% and considerably reduce emissions of other polluting particles. The advantage of scrubbers is the ability for shipping companies to continue to use cheaper bunker fuel rather than expensive low sulfur fuel. However, the scrubbing process only transfers the unwanted substance from the exhaust gases into a liquid or solid form. This material still requires disposal and there are often concerns surrounding disposal methods.
Internal engine modifications aim to reduce NOx production during the combustion process. Techniques such as water injection and exhaust gas reticulation can reduce NOx emissions by as much as 50%.
Humid Air Motor (HAM)
HAM technology is able to reduce NOx formation by up to 80%. In HAM systems water vapor is added to combustion air to reduce temperature peaks in the combustion chamber, which are normally the main reason for NOx formation.
Selective Catalytic Reduction (SCR)
SCR is an active emissions management system used to treat exhaust gasses after formation but prior to discharge into the atmosphere. Catalytic Reduction utilizes a chemical reaction to convert NOx into nitrogen, water and tiny amounts of carbon dioxide (CO2). SCR technology can reduce NOx emissions by up to 90%.
Shore Side Electricity
Shore side Electricity allows ships to turn off their engines and plug into an electrical grid while at berth and has been steadily growing in popularity as a reliable solution to cutting shipping emissions. However, adoption has also been hindered by a general distrust in the industry over high initial investment costs and the lack of a level playing field in international regulations.
This list is by no means exhaustive but instead gives an indication as to the range of technologies available to reduce ship pollution. Nevertheless, regardless of which control measures are utilized the first step to reducing air pollution from ships and port areas is to quantify it.
How can Aeroqual help?
Our speciality is helping people and governments get better air quality information. Our compact air quality monitoring systems provide the optimum balance between accuracy and affordability. Their modular design makes any combination of gases possible and they are able simultaneously monitor all major air pollution from ships and port activities. With ‘near reference’ performance our products can be used to measure pollutants at levels required by most international ambient air quality standards.
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